Building Your First Network
===========================

.. note:: These instructions have been verified to work against the
          latest stable Docker images and the pre-compiled
          setup utilities within the supplied tar file. If you run
          these commands with images or tools from the current master
          branch, it is possible that you will see configuration and panic
          errors.

The build your first network (BYFN) scenario provisions a sample Hyperledger
Fabric network consisting of two organizations, each maintaining two peer
nodes. It also will deploy a "Solo" ordering service by default, though other
ordering service implementations are available.

Install prerequisites
---------------------

Before we begin, if you haven't already done so, you may wish to check that
you have all the :doc:`prereqs` installed on the platform(s) on which you'll be
developing blockchain applications and/or operating Hyperledger Fabric.

You will also need to :doc:`install`. You will notice that there are a number of
samples included in the ``fabric-samples`` repository. We will be using the
``first-network`` sample. Let's open that sub-directory now.

.. code:: bash

  cd fabric-samples/first-network

.. note:: The supplied commands in this documentation **MUST** be run from your
          ``first-network`` sub-directory of the ``fabric-samples`` repository
          clone.  If you elect to run the commands from a different location,
          the various provided scripts will be unable to find the binaries.

Want to run it now?
-------------------

We provide a fully annotated script --- ``byfn.sh`` --- that leverages these Docker
images to quickly bootstrap a Hyperledger Fabric network that by default is
comprised of four peers representing two different organizations, and an orderer
node. It will also launch a container to run a scripted execution that will join
peers to a channel, deploy a chaincode and drive execution of transactions
against the deployed chaincode.

Here's the help text for the ``byfn.sh`` script:

.. code:: bash

  Usage:
  byfn.sh <mode> [-c <channel name>] [-t <timeout>] [-d <delay>] [-f <docker-compose-file>] [-s <dbtype>] [-l <language>] [-o <consensus-type>] [-i <imagetag>] [-v]"
    <mode> - one of 'up', 'down', 'restart', 'generate' or 'upgrade'"
      - 'up' - bring up the network with docker-compose up"
      - 'down' - clear the network with docker-compose down"
      - 'restart' - restart the network"
      - 'generate' - generate required certificates and genesis block"
      - 'upgrade'  - upgrade the network from version 1.3.x to 1.4.0"
    -c <channel name> - channel name to use (defaults to \"mychannel\")"
    -t <timeout> - CLI timeout duration in seconds (defaults to 10)"
    -d <delay> - delay duration in seconds (defaults to 3)"
    -f <docker-compose-file> - specify which docker-compose file use (defaults to docker-compose-cli.yaml)"
    -s <dbtype> - the database backend to use: goleveldb (default) or couchdb"
    -l <language> - the chaincode language: golang (default), node, or java"
    -o <consensus-type> - the consensus-type of the ordering service: solo (default), kafka, or etcdraft"
    -i <imagetag> - the tag to be used to launch the network (defaults to \"latest\")"
    -v - verbose mode"
  byfn.sh -h (print this message)"

  Typically, one would first generate the required certificates and
  genesis block, then bring up the network. e.g.:"

    byfn.sh generate -c mychannel"
    byfn.sh up -c mychannel -s couchdb"
    byfn.sh up -c mychannel -s couchdb -i 1.4.0"
    byfn.sh up -l node"
    byfn.sh down -c mychannel"
    byfn.sh upgrade -c mychannel"

  Taking all defaults:"
  	byfn.sh generate"
  	byfn.sh up"
  	byfn.sh down"

If you choose not to supply a flag, the script will use default values.

Generate Network Artifacts
^^^^^^^^^^^^^^^^^^^^^^^^^^

Ready to give it a go? Okay then! Execute the following command:

.. code:: bash

  ./byfn.sh generate

You will see a brief description as to what will occur, along with a yes/no command line
prompt. Respond with a ``y`` or hit the return key to execute the described action.

.. code:: bash

  Generating certs and genesis block for channel 'mychannel' with CLI timeout of '10' seconds and CLI delay of '3' seconds
  Continue? [Y/n] y
  proceeding ...
  /Users/xxx/dev/fabric-samples/bin/cryptogen

  ##########################################################
  ##### Generate certificates using cryptogen tool #########
  ##########################################################
  org1.example.com
  2017-06-12 21:01:37.334 EDT [bccsp] GetDefault -> WARN 001 Before using BCCSP, please call InitFactories(). Falling back to bootBCCSP.
  ...

  /Users/xxx/dev/fabric-samples/bin/configtxgen
  ##########################################################
  #########  Generating Orderer Genesis block ##############
  ##########################################################
  2017-06-12 21:01:37.558 EDT [common/configtx/tool] main -> INFO 001 Loading configuration
  2017-06-12 21:01:37.562 EDT [msp] getMspConfig -> INFO 002 intermediate certs folder not found at [/Users/xxx/dev/byfn/crypto-config/ordererOrganizations/example.com/msp/intermediatecerts]. Skipping.: [stat /Users/xxx/dev/byfn/crypto-config/ordererOrganizations/example.com/msp/intermediatecerts: no such file or directory]
  ...
  2017-06-12 21:01:37.588 EDT [common/configtx/tool] doOutputBlock -> INFO 00b Generating genesis block
  2017-06-12 21:01:37.590 EDT [common/configtx/tool] doOutputBlock -> INFO 00c Writing genesis block

  #################################################################
  ### Generating channel configuration transaction 'channel.tx' ###
  #################################################################
  2017-06-12 21:01:37.634 EDT [common/configtx/tool] main -> INFO 001 Loading configuration
  2017-06-12 21:01:37.644 EDT [common/configtx/tool] doOutputChannelCreateTx -> INFO 002 Generating new channel configtx
  2017-06-12 21:01:37.645 EDT [common/configtx/tool] doOutputChannelCreateTx -> INFO 003 Writing new channel tx

  #################################################################
  #######    Generating anchor peer update for Org1MSP   ##########
  #################################################################
  2017-06-12 21:01:37.674 EDT [common/configtx/tool] main -> INFO 001 Loading configuration
  2017-06-12 21:01:37.678 EDT [common/configtx/tool] doOutputAnchorPeersUpdate -> INFO 002 Generating anchor peer update
  2017-06-12 21:01:37.679 EDT [common/configtx/tool] doOutputAnchorPeersUpdate -> INFO 003 Writing anchor peer update

  #################################################################
  #######    Generating anchor peer update for Org2MSP   ##########
  #################################################################
  2017-06-12 21:01:37.700 EDT [common/configtx/tool] main -> INFO 001 Loading configuration
  2017-06-12 21:01:37.704 EDT [common/configtx/tool] doOutputAnchorPeersUpdate -> INFO 002 Generating anchor peer update
  2017-06-12 21:01:37.704 EDT [common/configtx/tool] doOutputAnchorPeersUpdate -> INFO 003 Writing anchor peer update

This first step generates all of the certificates and keys for our various
network entities, the ``genesis block`` used to bootstrap the ordering service,
and a collection of configuration transactions required to configure a
:ref:`Channel`.

Bring Up the Network
^^^^^^^^^^^^^^^^^^^^

Next, you can bring the network up with one of the following commands:

.. code:: bash

  ./byfn.sh up

The above command will compile Golang chaincode images and spin up the corresponding
containers. Go is the default chaincode language, however there is also support
for `Node.js <https://fabric-shim.github.io/>`_ and `Java <https://fabric-chaincode-java.github.io/>`_
chaincode. If you'd like to run through this tutorial with node chaincode, pass
the following command instead:

.. code:: bash

  # we use the -l flag to specify the chaincode language
  # forgoing the -l flag will default to Golang

  ./byfn.sh up -l node

.. note:: For more information on the Node.js shim, please refer to its
          `documentation <https://fabric-shim.github.io/ChaincodeInterface.html>`_.

.. note:: For more information on the Java shim, please refer to its
          `documentation <https://fabric-chaincode-java.github.io/org/hyperledger/fabric/shim/Chaincode.html>`_.

Тo make the sample run with Java chaincode, you have to specify ``-l java`` as follows:

.. code:: bash

  ./byfn.sh up -l java

.. note:: Do not run both of these commands. Only one language can be tried unless
          you bring down and recreate the network between.

In addition to support for multiple chaincode languages, you can also issue a
flag that will bring up a five node Raft ordering service or a Kafka ordering
service instead of the one node Solo orderer. For more information about the
currently supported ordering service implementations, check out :doc:`orderer/ordering_service`.

To bring up the network with a Raft ordering service, issue:

.. code:: bash

  ./byfn.sh up -o etcdraft

To bring up the network with a Kafka ordering service, issue:

.. code:: bash

  ./byfn.sh up -o kafka

Once again, you will be prompted as to whether you wish to continue or abort.
Respond with a ``y`` or hit the return key:

.. code:: bash

  Starting for channel 'mychannel' with CLI timeout of '10' seconds and CLI delay of '3' seconds
  Continue? [Y/n]
  proceeding ...
  Creating network "net_byfn" with the default driver
  Creating peer0.org1.example.com
  Creating peer1.org1.example.com
  Creating peer0.org2.example.com
  Creating orderer.example.com
  Creating peer1.org2.example.com
  Creating cli


   ____    _____      _      ____    _____
  / ___|  |_   _|    / \    |  _ \  |_   _|
  \___ \    | |     / _ \   | |_) |   | |
   ___) |   | |    / ___ \  |  _ <    | |
  |____/    |_|   /_/   \_\ |_| \_\   |_|

  Channel name : mychannel
  Creating channel...

The logs will continue from there. This will launch all of the containers, and
then drive a complete end-to-end application scenario. Upon successful
completion, it should report the following in your terminal window:

.. code:: bash

    Query Result: 90
    2017-05-16 17:08:15.158 UTC [main] main -> INFO 008 Exiting.....
    ===================== Query successful on peer1.org2 on channel 'mychannel' =====================

    ===================== All GOOD, BYFN execution completed =====================


     _____   _   _   ____
    | ____| | \ | | |  _ \
    |  _|   |  \| | | | | |
    | |___  | |\  | | |_| |
    |_____| |_| \_| |____/

You can scroll through these logs to see the various transactions. If you don't
get this result, then jump down to the :ref:`Troubleshoot` section and let's see
whether we can help you discover what went wrong.

Bring Down the Network
^^^^^^^^^^^^^^^^^^^^^^

Finally, let's bring it all down so we can explore the network setup one step
at a time. The following will kill your containers, remove the crypto material
and four artifacts, and delete the chaincode images from your Docker Registry:

.. code:: bash

  ./byfn.sh down

Once again, you will be prompted to continue, respond with a ``y`` or hit the return key:

.. code:: bash

  Stopping with channel 'mychannel' and CLI timeout of '10'
  Continue? [Y/n] y
  proceeding ...
  WARNING: The CHANNEL_NAME variable is not set. Defaulting to a blank string.
  WARNING: The TIMEOUT variable is not set. Defaulting to a blank string.
  Removing network net_byfn
  468aaa6201ed
  ...
  Untagged: dev-peer1.org2.example.com-mycc-1.0:latest
  Deleted: sha256:ed3230614e64e1c83e510c0c282e982d2b06d148b1c498bbdcc429e2b2531e91
  ...

If you'd like to learn more about the underlying tooling and bootstrap mechanics,
continue reading.  In these next sections we'll walk through the various steps
and requirements to build a fully-functional Hyperledger Fabric network.

.. note:: The manual steps outlined below assume that the ``FABRIC_LOGGING_SPEC`` in
          the ``cli`` container is set to ``DEBUG``. You can set this by modifying
          the ``docker-compose-cli.yaml`` file in the ``first-network`` directory.
          e.g.

          .. code::

            cli:
              container_name: cli
              image: hyperledger/fabric-tools:$IMAGE_TAG
              tty: true
              stdin_open: true
              environment:
                - GOPATH=/opt/gopath
                - CORE_VM_ENDPOINT=unix:///host/var/run/docker.sock
                - FABRIC_LOGGING_SPEC=DEBUG
                #- FABRIC_LOGGING_SPEC=INFO

Crypto Generator
----------------

We will use the ``cryptogen`` tool to generate the cryptographic material
(x509 certs and signing keys) for our various network entities.  These certificates are
representative of identities, and they allow for sign/verify authentication to
take place as our entities communicate and transact.

How does it work?
^^^^^^^^^^^^^^^^^

Cryptogen consumes a file --- ``crypto-config.yaml`` --- that contains the network
topology and allows us to generate a set of certificates and keys for both the
Organizations and the components that belong to those Organizations.  Each
Organization is provisioned a unique root certificate (``ca-cert``) that binds
specific components (peers and orderers) to that Org.  By assigning each
Organization a unique CA certificate, we are mimicking a typical network where
a participating :ref:`Member` would use its own Certificate Authority.
Transactions and communications within Hyperledger Fabric are signed by an
entity's private key (``keystore``), and then verified by means of a public
key (``signcerts``).

You will notice a ``count`` variable within this file. We use this to specify
the number of peers per Organization; in our case there are two peers per Org.
We won't delve into the minutiae of `x.509 certificates and public key
infrastructure <https://en.wikipedia.org/wiki/Public_key_infrastructure>`_
right now. If you're interested, you can peruse these topics on your own time.

After we run the ``cryptogen`` tool, the generated certificates and keys will be
saved to a folder titled ``crypto-config``. Note that the ``crypto-config.yaml``
file lists five orderers as being tied to the orderer organization. While the
``cryptogen`` tool will create certificates for all five of these orderers, unless
the Raft or Kafka ordering services are being used, only one of these orderers
will be used in a Solo ordering service implementation and be used to create the
system channel and ``mychannel``.

Configuration Transaction Generator
-----------------------------------

The ``configtxgen`` tool is used to create four configuration artifacts:

  * orderer ``genesis block``,
  * channel ``configuration transaction``,
  * and two ``anchor peer transactions`` - one for each Peer Org.

Please see :doc:`commands/configtxgen` for a complete description of this tool's functionality.

The orderer block is the :ref:`Genesis-Block` for the ordering service, and the
channel configuration transaction file is broadcast to the orderer at :ref:`Channel` creation
time.  The anchor peer transactions, as the name might suggest, specify each
Org's :ref:`Anchor-Peer` on this channel.

How does it work?
^^^^^^^^^^^^^^^^^

Configtxgen consumes a file - ``configtx.yaml`` - that contains the definitions
for the sample network. There are three members - one Orderer Org (``OrdererOrg``)
and two Peer Orgs (``Org1`` & ``Org2``) each managing and maintaining two peer nodes.
This file also specifies a consortium - ``SampleConsortium`` - consisting of our
two Peer Orgs.  Pay specific attention to the "Profiles" section at the bottom of
this file. You will notice that we have several unique profiles. A few are worth
noting:

* ``TwoOrgsOrdererGenesis``: generates the genesis block for a Solo ordering
  service.

* ``SampleMultiNodeEtcdRaft``: generates the genesis block for a Raft ordering
  service. Only used if you issue the ``-o`` flag and specify ``etcdraft``.

* ``SampleDevModeKafka``: generates the genesis block for a Kafka ordering
  service. Only used if you issue the ``-o`` flag and specify ``kafka``.

* ``TwoOrgsChannel``: generates the genesis block for our channel, ``mychannel``.

These headers are important, as we will pass them in as arguments when we create
our artifacts.

.. note:: Notice that our ``SampleConsortium`` is defined in
          the system-level profile and then referenced by
          our channel-level profile.  Channels exist within
          the purview of a consortium, and all consortia
          must be defined in the scope of the network at
          large.

This file also contains two additional specifications that are worth
noting. Firstly, we specify the anchor peers for each Peer Org
(``peer0.org1.example.com`` & ``peer0.org2.example.com``).  Secondly, we point to
the location of the MSP directory for each member, in turn allowing us to store the
root certificates for each Org in the orderer genesis block.  This is a critical
concept. Now any network entity communicating with the ordering service can have
its digital signature verified.

Run the tools
-------------

You can manually generate the certificates/keys and the various configuration
artifacts using the ``configtxgen`` and ``cryptogen`` commands. Alternately,
you could try to adapt the byfn.sh script to accomplish your objectives.

Manually generate the artifacts
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You can refer to the ``generateCerts`` function in the byfn.sh script for the
commands necessary to generate the certificates that will be used for your
network configuration as defined in the ``crypto-config.yaml`` file. However,
for the sake of convenience, we will also provide a reference here.

First let's run the ``cryptogen`` tool.  Our binary is in the ``bin``
directory, so we need to provide the relative path to where the tool resides.

.. code:: bash

    ../bin/cryptogen generate --config=./crypto-config.yaml

You should see the following in your terminal:

.. code:: bash

  org1.example.com
  org2.example.com

The certs and keys (i.e. the MSP material) will be output into a directory - ``crypto-config`` -
at the root of the ``first-network`` directory.

Next, we need to tell the ``configtxgen`` tool where to look for the
``configtx.yaml`` file that it needs to ingest.  We will tell it look in our
present working directory:

.. code:: bash

    export FABRIC_CFG_PATH=$PWD

Then, we'll invoke the ``configtxgen`` tool to create the orderer genesis block:

.. code:: bash

    ../bin/configtxgen -profile TwoOrgsOrdererGenesis -channelID byfn-sys-channel -outputBlock ./channel-artifacts/genesis.block

To output a genesis block for a Raft ordering service, this command should be:

.. code:: bash

  ../bin/configtxgen -profile SampleMultiNodeEtcdRaft -channelID byfn-sys-channel -outputBlock ./channel-artifacts/genesis.block

Note the ``SampleMultiNodeEtcdRaft`` profile being used here.

To output a genesis block for a Kafka ordering service, issue:

.. code:: bash

  ../bin/configtxgen -profile SampleDevModeKafka -channelID byfn-sys-channel -outputBlock ./channel-artifacts/genesis.block

If you are not using Raft or Kafka, you should see an output similar to the
following:

.. code:: bash

  2017-10-26 19:21:56.301 EDT [common/tools/configtxgen] main -> INFO 001 Loading configuration
  2017-10-26 19:21:56.309 EDT [common/tools/configtxgen] doOutputBlock -> INFO 002 Generating genesis block
  2017-10-26 19:21:56.309 EDT [common/tools/configtxgen] doOutputBlock -> INFO 003 Writing genesis block

.. note:: The orderer genesis block and the subsequent artifacts we are about to create
          will be output into the ``channel-artifacts`` directory at the root of this
          project. The `channelID` in the above command is the name of the system channel.

.. _createchanneltx:

Create a Channel Configuration Transaction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Next, we need to create the channel transaction artifact. Be sure to replace ``$CHANNEL_NAME`` or
set ``CHANNEL_NAME`` as an environment variable that can be used throughout these instructions:

.. code:: bash

    # The channel.tx artifact contains the definitions for our sample channel

    export CHANNEL_NAME=mychannel  && ../bin/configtxgen -profile TwoOrgsChannel -outputCreateChannelTx ./channel-artifacts/channel.tx -channelID $CHANNEL_NAME

Note that you don't have to issue a special command for the channel if you are
using a Raft or Kafka ordering service. The ``TwoOrgsChannel`` profile will use
the ordering service configuration you specified when creating the genesis block
for the network.

If you are not using a Raft or Kafka ordering service, you should see an output
similar to the following in your terminal:

.. code:: bash

  2017-10-26 19:24:05.324 EDT [common/tools/configtxgen] main -> INFO 001 Loading configuration
  2017-10-26 19:24:05.329 EDT [common/tools/configtxgen] doOutputChannelCreateTx -> INFO 002 Generating new channel configtx
  2017-10-26 19:24:05.329 EDT [common/tools/configtxgen] doOutputChannelCreateTx -> INFO 003 Writing new channel tx

Next, we will define the anchor peer for Org1 on the channel that we are
constructing. Again, be sure to replace ``$CHANNEL_NAME`` or set the environment
variable for the following commands.  The terminal output will mimic that of the
channel transaction artifact:

.. code:: bash

    ../bin/configtxgen -profile TwoOrgsChannel -outputAnchorPeersUpdate ./channel-artifacts/Org1MSPanchors.tx -channelID $CHANNEL_NAME -asOrg Org1MSP

Now, we will define the anchor peer for Org2 on the same channel:

.. code:: bash

    ../bin/configtxgen -profile TwoOrgsChannel -outputAnchorPeersUpdate ./channel-artifacts/Org2MSPanchors.tx -channelID $CHANNEL_NAME -asOrg Org2MSP

Start the network
-----------------

.. note:: If you ran the ``byfn.sh`` example above previously, be sure that you
          have brought down the test network before you proceed (see
          `Bring Down the Network`_).

We will leverage a script to spin up our network. The
docker-compose file references the images that we have previously downloaded,
and bootstraps the orderer with our previously generated ``genesis.block``.

We want to go through the commands manually in order to expose the
syntax and functionality of each call.

First let's start our network:

.. code:: bash

    docker-compose -f docker-compose-cli.yaml up -d

If you want to see the realtime logs for your network, then do not supply the ``-d`` flag.
If you let the logs stream, then you will need to open a second terminal to execute the CLI calls.

.. _createandjoin:

.. _peerenvvars:

Create & Join Channel
^^^^^^^^^^^^^^^^^^^^^

Recall that we created the channel configuration transaction using the
``configtxgen`` tool in the :ref:`createchanneltx` section, above. You can
repeat that process to create additional channel configuration transactions,
using the same or different profiles in the ``configtx.yaml`` that you pass
to the ``configtxgen`` tool. Then you can repeat the process defined in this
section to establish those other channels in your network.

We will enter the CLI container using the ``docker exec`` command:

.. code:: bash

        docker exec -it cli bash

If successful you should see the following:

.. code:: bash

        root@0d78bb69300d:/opt/gopath/src/github.com/hyperledger/fabric/peer#

For the following CLI commands to work, we need to preface our commands with the
four environment variables given below.  These variables for
``peer0.org1.example.com`` are baked into the CLI container, therefore we can
operate without passing them. **HOWEVER**, if you want to send calls to other peers
or the orderer, override the environment variables as seen in the example below
when you make any CLI calls:

.. code:: bash

    # Environment variables for PEER0

    CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
    CORE_PEER_ADDRESS=peer0.org1.example.com:7051
    CORE_PEER_LOCALMSPID="Org1MSP"
    CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt

.. _createandjoin:

Next, we are going to pass in the generated channel configuration transaction
artifact that we created in the :ref:`createchanneltx` section (we called
it ``channel.tx``) to the orderer as part of the create channel request.

We specify our channel name with the ``-c`` flag and our channel configuration
transaction with the ``-f`` flag. In this case it is ``channel.tx``, however
you can mount your own configuration transaction with a different name.  Once again
we will set the ``CHANNEL_NAME`` environment variable within our CLI container so that
we don't have to explicitly pass this argument. Channel names must be all lower
case, less than 250 characters long and match the regular expression
``[a-z][a-z0-9.-]*``.

.. code:: bash

        export CHANNEL_NAME=mychannel

        # the channel.tx file is mounted in the channel-artifacts directory within your CLI container
        # as a result, we pass the full path for the file
        # we also pass the path for the orderer ca-cert in order to verify the TLS handshake
        # be sure to export or replace the $CHANNEL_NAME variable appropriately

        peer channel create -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/channel.tx --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem

.. note:: Notice the ``--cafile`` that we pass as part of this command.  It is
          the local path to the orderer's root cert, allowing us to verify the
          TLS handshake.

This command returns a genesis block - ``<CHANNEL_NAME.block>`` - which we will use to join the channel.
It contains the configuration information specified in ``channel.tx``  If you have not
made any modifications to the default channel name, then the command will return you a
proto titled ``mychannel.block``.

.. note:: You will remain in the CLI container for the remainder of
          these manual commands. You must also remember to preface all commands
          with the corresponding environment variables when targeting a peer other than
          ``peer0.org1.example.com``.

Now let's join ``peer0.org1.example.com`` to the channel.

.. code:: bash

        # By default, this joins ``peer0.org1.example.com`` only
        # the <CHANNEL_NAME.block> was returned by the previous command
        # if you have not modified the channel name, you will join with mychannel.block
        # if you have created a different channel name, then pass in the appropriately named block

         peer channel join -b mychannel.block

You can make other peers join the channel as necessary by making appropriate
changes in the four environment variables we used in the :ref:`peerenvvars`
section, above.

Rather than join every peer, we will simply join ``peer0.org2.example.com`` so that
we can properly update the anchor peer definitions in our channel.  Since we are
overriding the default environment variables baked into the CLI container, this full
command will be the following:

.. code:: bash

  CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp CORE_PEER_ADDRESS=peer0.org2.example.com:9051 CORE_PEER_LOCALMSPID="Org2MSP" CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt peer channel join -b mychannel.block


.. note:: Prior to v1.4.1 all peers within the docker network used port ``7051``.
          If using a version of fabric-samples prior to v1.4.1, modify all
          occurrences of ``CORE_PEER_ADDRESS`` in this tutorial to use port ``7051``.

Alternatively, you could choose to set these environment variables individually
rather than passing in the entire string.  Once they've been set, you simply need
to issue the ``peer channel join`` command again and the CLI container will act
on behalf of ``peer0.org2.example.com``.

Update the anchor peers
^^^^^^^^^^^^^^^^^^^^^^^

The following commands are channel updates and they will propagate to the definition
of the channel.  In essence, we adding additional configuration information on top
of the channel's genesis block.  Note that we are not modifying the genesis block, but
simply adding deltas into the chain that will define the anchor peers.

Update the channel definition to define the anchor peer for Org1 as ``peer0.org1.example.com``:

.. code:: bash

  peer channel update -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/Org1MSPanchors.tx --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem

Now update the channel definition to define the anchor peer for Org2 as ``peer0.org2.example.com``.
Identically to the ``peer channel join`` command for the Org2 peer, we will need to
preface this call with the appropriate environment variables.

.. code:: bash

  CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp CORE_PEER_ADDRESS=peer0.org2.example.com:9051 CORE_PEER_LOCALMSPID="Org2MSP" CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt peer channel update -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/Org2MSPanchors.tx --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem

Install & Instantiate Chaincode
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. note:: We will utilize a simple existing chaincode. To learn how to write
          your own chaincode, see the :doc:`chaincode4ade` tutorial.

Applications interact with the blockchain ledger through ``chaincode``.  As
such we need to install the chaincode on every peer that will execute and
endorse our transactions, and then instantiate the chaincode on the channel.

First, install the sample Go, Node.js or Java chaincode onto the peer0
node in Org1. These commands place the specified source
code flavor onto our peer's filesystem.

.. note:: You can only install one version of the source code per chaincode name
          and version.  The source code exists on the peer's file system in the
          context of chaincode name and version; it is language agnostic.  Similarly
          the instantiated chaincode container will be reflective of whichever
          language has been installed on the peer.

**Golang**

.. code:: bash

    # this installs the Go chaincode. For go chaincode -p takes the relative path from $GOPATH/src
    peer chaincode install -n mycc -v 1.0 -p github.com/chaincode/chaincode_example02/go/

**Node.js**

.. code:: bash

    # this installs the Node.js chaincode
    # make note of the -l flag to indicate "node" chaincode
    # for node chaincode -p takes the absolute path to the node.js chaincode
    peer chaincode install -n mycc -v 1.0 -l node -p /opt/gopath/src/github.com/chaincode/chaincode_example02/node/

**Java**

.. code:: bash

    # make note of the -l flag to indicate "java" chaincode
    # for java chaincode -p takes the absolute path to the java chaincode
    peer chaincode install -n mycc -v 1.0 -l java -p /opt/gopath/src/github.com/chaincode/chaincode_example02/java/

When we instantiate the chaincode on the channel, the endorsement policy will be
set to require endorsements from a peer in both Org1 and Org2. Therefore, we
also need to install the chaincode on a peer in Org2.

Modify the following four environment variables to issue the install command
against peer0 in Org2:

.. code:: bash

   # Environment variables for PEER0 in Org2

   CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp
   CORE_PEER_ADDRESS=peer0.org2.example.com:9051
   CORE_PEER_LOCALMSPID="Org2MSP"
   CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt

Now install the sample Go, Node.js or Java chaincode onto a peer0
in Org2. These commands place the specified source
code flavor onto our peer's filesystem.

**Golang**

.. code:: bash

    # this installs the Go chaincode. For go chaincode -p takes the relative path from $GOPATH/src
    peer chaincode install -n mycc -v 1.0 -p github.com/chaincode/chaincode_example02/go/

**Node.js**

.. code:: bash

    # this installs the Node.js chaincode
    # make note of the -l flag to indicate "node" chaincode
    # for node chaincode -p takes the absolute path to the node.js chaincode
    peer chaincode install -n mycc -v 1.0 -l node -p /opt/gopath/src/github.com/chaincode/chaincode_example02/node/

**Java**

.. code:: bash

    # make note of the -l flag to indicate "java" chaincode
    # for java chaincode -p takes the absolute path to the java chaincode
    peer chaincode install -n mycc -v 1.0 -l java -p /opt/gopath/src/github.com/chaincode/chaincode_example02/java/


Next, instantiate the chaincode on the channel. This will initialize the
chaincode on the channel, set the endorsement policy for the chaincode, and
launch a chaincode container for the targeted peer.  Take note of the ``-P``
argument. This is our policy where we specify the required level of endorsement
for a transaction against this chaincode to be validated.

In the command below you’ll notice that we specify our policy as
``-P "AND ('Org1MSP.peer','Org2MSP.peer')"``. This means that we need
“endorsement” from a peer belonging to Org1 **AND** Org2 (i.e. two endorsement).
If we changed the syntax to ``OR`` then we would need only one endorsement.

**Golang**

.. code:: bash

    # be sure to replace the $CHANNEL_NAME environment variable if you have not exported it
    # if you did not install your chaincode with a name of mycc, then modify that argument as well

    peer chaincode instantiate -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n mycc -v 1.0 -c '{"Args":["init","a", "100", "b","200"]}' -P "AND ('Org1MSP.peer','Org2MSP.peer')"

**Node.js**

.. note::  The instantiation of the Node.js chaincode will take roughly a minute.
           The command is not hanging; rather it is installing the fabric-shim
           layer as the image is being compiled.

.. code:: bash

    # be sure to replace the $CHANNEL_NAME environment variable if you have not exported it
    # if you did not install your chaincode with a name of mycc, then modify that argument as well
    # notice that we must pass the -l flag after the chaincode name to identify the language

    peer chaincode instantiate -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n mycc -l node -v 1.0 -c '{"Args":["init","a", "100", "b","200"]}' -P "AND ('Org1MSP.peer','Org2MSP.peer')"

**Java**

.. note:: Please note, Java chaincode instantiation might take time as it compiles chaincode and
          downloads docker container with java environment.

.. code:: bash

    peer chaincode instantiate -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n mycc -l java -v 1.0 -c '{"Args":["init","a", "100", "b","200"]}' -P "AND ('Org1MSP.peer','Org2MSP.peer')"

See the `endorsement
policies <http://hyperledger-fabric.readthedocs.io/en/latest/endorsement-policies.html>`__
documentation for more details on policy implementation.

If you want additional peers to interact with ledger, then you will need to join
them to the channel, and install the same name, version and language of the
chaincode source onto the appropriate peer's filesystem.  A chaincode container
will be launched for each peer as soon as they try to interact with that specific
chaincode.  Again, be cognizant of the fact that the Node.js images will be slower
to compile.

Once the chaincode has been instantiated on the channel, we can forgo the ``l``
flag.  We need only pass in the channel identifier and name of the chaincode.

Query
^^^^^

Let's query for the value of ``a`` to make sure the chaincode was properly
instantiated and the state DB was populated. The syntax for query is as follows:

.. code:: bash

  # be sure to set the -C and -n flags appropriately

  peer chaincode query -C $CHANNEL_NAME -n mycc -c '{"Args":["query","a"]}'

Invoke
^^^^^^

Now let's move ``10`` from ``a`` to ``b``.  This transaction will cut a new block and
update the state DB. The syntax for invoke is as follows:

.. code:: bash

    # be sure to set the -C and -n flags appropriately

    peer chaincode invoke -o orderer.example.com:7050 --tls true --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n mycc --peerAddresses peer0.org1.example.com:7051 --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt --peerAddresses peer0.org2.example.com:9051 --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt -c '{"Args":["invoke","a","b","10"]}'

Query
^^^^^

Let's confirm that our previous invocation executed properly. We initialized the
key ``a`` with a value of ``100`` and just removed ``10`` with our previous
invocation. Therefore, a query against ``a`` should return ``90``. The syntax
for query is as follows.

.. code:: bash

  # be sure to set the -C and -n flags appropriately

  peer chaincode query -C $CHANNEL_NAME -n mycc -c '{"Args":["query","a"]}'

We should see the following:

.. code:: bash

   Query Result: 90

Feel free to start over and manipulate the key value pairs and subsequent
invocations.

Install
^^^^^^^

Now we will install the chaincode on a third peer, peer1 in Org2. Modify the
following four environment variables to issue the install command
against peer1 in Org2:

.. code:: bash

   # Environment variables for PEER1 in Org2

   CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp
   CORE_PEER_ADDRESS=peer1.org2.example.com:10051
   CORE_PEER_LOCALMSPID="Org2MSP"
   CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer1.org2.example.com/tls/ca.crt

Now install the sample Go, Node.js or Java chaincode onto peer1
in Org2. These commands place the specified source
code flavor onto our peer's filesystem.

**Golang**

.. code:: bash

    # this installs the Go chaincode. For go chaincode -p takes the relative path from $GOPATH/src
    peer chaincode install -n mycc -v 1.0 -p github.com/chaincode/chaincode_example02/go/

**Node.js**

.. code:: bash

    # this installs the Node.js chaincode
    # make note of the -l flag to indicate "node" chaincode
    # for node chaincode -p takes the absolute path to the node.js chaincode
    peer chaincode install -n mycc -v 1.0 -l node -p /opt/gopath/src/github.com/chaincode/chaincode_example02/node/

**Java**

.. code:: bash

    # make note of the -l flag to indicate "java" chaincode
    # for java chaincode -p takes the absolute path to the java chaincode
    peer chaincode install -n mycc -v 1.0 -l java -p /opt/gopath/src/github.com/chaincode/chaincode_example02/java/

Query
^^^^^

Let's confirm that we can issue the query to Peer1 in Org2. We initialized the
key ``a`` with a value of ``100`` and just removed ``10`` with our previous
invocation. Therefore, a query against ``a`` should still return ``90``.

peer1 in Org2 must first join the channel before it can respond to queries. The
channel can be joined by issuing the following command:

.. code:: bash

  CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp CORE_PEER_ADDRESS=peer1.org2.example.com:10051 CORE_PEER_LOCALMSPID="Org2MSP" CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer1.org2.example.com/tls/ca.crt peer channel join -b mychannel.block

After the join command returns, the query can be issued. The syntax
for query is as follows.

.. code:: bash

  # be sure to set the -C and -n flags appropriately

  peer chaincode query -C $CHANNEL_NAME -n mycc -c '{"Args":["query","a"]}'

We should see the following:

.. code:: bash

   Query Result: 90

Feel free to start over and manipulate the key value pairs and subsequent
invocations.


.. _behind-scenes:

What's happening behind the scenes?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. note:: These steps describe the scenario in which
          ``script.sh`` is run by './byfn.sh up'.  Clean your network
          with ``./byfn.sh down`` and ensure
          this command is active.  Then use the same
          docker-compose prompt to launch your network again

-  A script - ``script.sh`` - is baked inside the CLI container. The
   script drives the ``createChannel`` command against the supplied channel name
   and uses the channel.tx file for channel configuration.

-  The output of ``createChannel`` is a genesis block -
   ``<your_channel_name>.block`` - which gets stored on the peers' file systems and contains
   the channel configuration specified from channel.tx.

-  The ``joinChannel`` command is exercised for all four peers, which takes as
   input the previously generated genesis block.  This command instructs the
   peers to join ``<your_channel_name>`` and create a chain starting with ``<your_channel_name>.block``.

-  Now we have a channel consisting of four peers, and two
   organizations.  This is our ``TwoOrgsChannel`` profile.

-  ``peer0.org1.example.com`` and ``peer1.org1.example.com`` belong to Org1;
   ``peer0.org2.example.com`` and ``peer1.org2.example.com`` belong to Org2

-  These relationships are defined through the ``crypto-config.yaml`` and
   the MSP path is specified in our docker compose.

-  The anchor peers for Org1MSP (``peer0.org1.example.com``) and
   Org2MSP (``peer0.org2.example.com``) are then updated.  We do this by passing
   the ``Org1MSPanchors.tx`` and ``Org2MSPanchors.tx`` artifacts to the ordering
   service along with the name of our channel.

-  A chaincode - **chaincode_example02** - is installed on ``peer0.org1.example.com`` and
   ``peer0.org2.example.com``

-  The chaincode is then "instantiated" on ``mychannel``. Instantiation
   adds the chaincode to the channel, starts the container for the target peer,
   and initializes the key value pairs associated with the chaincode.  The initial
   values for this example are ["a","100" "b","200"]. This "instantiation" results
   in a container by the name of ``dev-peer0.org2.example.com-mycc-1.0`` starting.

-  The instantiation also passes in an argument for the endorsement
   policy. The policy is defined as
   ``-P "AND ('Org1MSP.peer','Org2MSP.peer')"``, meaning that any
   transaction must be endorsed by a peer tied to Org1 and Org2.

-  A query against the value of "a" is issued to ``peer0.org2.example.com``.
   A container for Org2 peer0 by the name of ``dev-peer0.org2.example.com-mycc-1.0``
   was started when the chaincode was instantiated. The result
   of the query is returned. No write operations have occurred, so
   a query against "a" will still return a value of "100".

-  An invoke is sent to ``peer0.org1.example.com`` and ``peer0.org2.example.com``
   to move "10" from "a" to "b"

-  A query is sent to ``peer0.org2.example.com`` for the value of "a". A
   value of 90 is returned, correctly reflecting the previous
   transaction during which the value for key "a" was modified by 10.

-  The chaincode - **chaincode_example02** - is installed on ``peer1.org2.example.com``

-  A query is sent to ``peer1.org2.example.com`` for the value of "a". This starts a
   third chaincode container by the name of ``dev-peer1.org2.example.com-mycc-1.0``. A
   value of 90 is returned, correctly reflecting the previous
   transaction during which the value for key "a" was modified by 10.

What does this demonstrate?
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Chaincode **MUST** be installed on a peer in order for it to
successfully perform read/write operations against the ledger.
Furthermore, a chaincode container is not started for a peer until an ``init`` or
traditional transaction - read/write - is performed against that chaincode (e.g. query for
the value of "a"). The transaction causes the container to start. Also,
all peers in a channel maintain an exact copy of the ledger which
comprises the blockchain to store the immutable, sequenced record in
blocks, as well as a state database to maintain a snapshot of the current state.
This includes those peers that do not have chaincode installed on them
(like ``peer1.org1.example.com`` in the above example) . Finally, the chaincode is accessible
after it is installed (like ``peer1.org2.example.com`` in the above example) because it
has already been instantiated.

How do I see these transactions?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Check the logs for the CLI Docker container.

.. code:: bash

        docker logs -f cli

You should see the following output:

.. code:: bash

      2017-05-16 17:08:01.366 UTC [msp] GetLocalMSP -> DEBU 004 Returning existing local MSP
      2017-05-16 17:08:01.366 UTC [msp] GetDefaultSigningIdentity -> DEBU 005 Obtaining default signing identity
      2017-05-16 17:08:01.366 UTC [msp/identity] Sign -> DEBU 006 Sign: plaintext: 0AB1070A6708031A0C08F1E3ECC80510...6D7963631A0A0A0571756572790A0161
      2017-05-16 17:08:01.367 UTC [msp/identity] Sign -> DEBU 007 Sign: digest: E61DB37F4E8B0D32C9FE10E3936BA9B8CD278FAA1F3320B08712164248285C54
      Query Result: 90
      2017-05-16 17:08:15.158 UTC [main] main -> INFO 008 Exiting.....
      ===================== Query successful on peer1.org2 on channel 'mychannel' =====================

      ===================== All GOOD, BYFN execution completed =====================


       _____   _   _   ____
      | ____| | \ | | |  _ \
      |  _|   |  \| | | | | |
      | |___  | |\  | | |_| |
      |_____| |_| \_| |____/

You can scroll through these logs to see the various transactions.

How can I see the chaincode logs?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Inspect the individual chaincode containers to see the separate
transactions executed against each container. Here is the combined
output from each container:

.. code:: bash

        $ docker logs dev-peer0.org2.example.com-mycc-1.0
        04:30:45.947 [BCCSP_FACTORY] DEBU : Initialize BCCSP [SW]
        ex02 Init
        Aval = 100, Bval = 200

        $ docker logs dev-peer0.org1.example.com-mycc-1.0
        04:31:10.569 [BCCSP_FACTORY] DEBU : Initialize BCCSP [SW]
        ex02 Invoke
        Query Response:{"Name":"a","Amount":"100"}
        ex02 Invoke
        Aval = 90, Bval = 210

        $ docker logs dev-peer1.org2.example.com-mycc-1.0
        04:31:30.420 [BCCSP_FACTORY] DEBU : Initialize BCCSP [SW]
        ex02 Invoke
        Query Response:{"Name":"a","Amount":"90"}

Understanding the Docker Compose topology
-----------------------------------------

The BYFN sample offers us two flavors of Docker Compose files, both of which
are extended from the ``docker-compose-base.yaml`` (located in the ``base``
folder).  Our first flavor, ``docker-compose-cli.yaml``, provides us with a
CLI container, along with an orderer, four peers.  We use this file
for the entirety of the instructions on this page.

.. note:: the remainder of this section covers a docker-compose file designed for the
          SDK.  Refer to the `Node SDK <https://github.com/hyperledger/fabric-sdk-node>`__
          repo for details on running these tests.

The second flavor, ``docker-compose-e2e.yaml``, is constructed to run end-to-end tests
using the Node.js SDK.  Aside from functioning with the SDK, its primary differentiation
is that there are containers for the fabric-ca servers.  As a result, we are able
to send REST calls to the organizational CAs for user registration and enrollment.

If you want to use the ``docker-compose-e2e.yaml`` without first running the
byfn.sh script, then we will need to make four slight modifications.
We need to point to the private keys for our Organization's CA's.  You can locate
these values in your crypto-config folder.  For example, to locate the private
key for Org1 we would follow this path - ``crypto-config/peerOrganizations/org1.example.com/ca/``.
The private key is a long hash value followed by ``_sk``.  The path for Org2
would be - ``crypto-config/peerOrganizations/org2.example.com/ca/``.

In the ``docker-compose-e2e.yaml`` update the FABRIC_CA_SERVER_TLS_KEYFILE variable
for ca0 and ca1.  You also need to edit the path that is provided in the command
to start the ca server.  You are providing the same private key twice for each
CA container.

Using CouchDB
-------------

The state database can be switched from the default (goleveldb) to CouchDB.
The same chaincode functions are available with CouchDB, however, there is the
added ability to perform rich and complex queries against the state database
data content contingent upon the chaincode data being modeled as JSON.

To use CouchDB instead of the default database (goleveldb), follow the same
procedures outlined earlier for generating the artifacts, except when starting
the network pass ``docker-compose-couch.yaml`` as well:

.. code:: bash

    docker-compose -f docker-compose-cli.yaml -f docker-compose-couch.yaml up -d

**chaincode_example02** should now work using CouchDB underneath.

.. note::  If you choose to implement mapping of the fabric-couchdb container
           port to a host port, please make sure you are aware of the security
           implications. Mapping of the port in a development environment makes the
           CouchDB REST API available, and allows the
           visualization of the database via the CouchDB web interface (Fauxton).
           Production environments would likely refrain from implementing port mapping in
           order to restrict outside access to the CouchDB containers.

You can use **chaincode_example02** chaincode against the CouchDB state database
using the steps outlined above, however in order to exercise the CouchDB query
capabilities you will need to use a chaincode that has data modeled as JSON,
(e.g. **marbles02**). You can locate the **marbles02** chaincode in the
``fabric/examples/chaincode/go`` directory.

We will follow the same process to create and join the channel as outlined in the
:ref:`createandjoin` section above.  Once you have joined your peer(s) to the
channel, use the following steps to interact with the **marbles02** chaincode:

-  Install and instantiate the chaincode on ``peer0.org1.example.com``:

.. code:: bash

       # be sure to modify the $CHANNEL_NAME variable accordingly for the instantiate command

       peer chaincode install -n marbles -v 1.0 -p github.com/chaincode/marbles02/go
       peer chaincode instantiate -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -v 1.0 -c '{"Args":["init"]}' -P "OR ('Org1MSP.peer','Org2MSP.peer')"

-  Create some marbles and move them around:

.. code:: bash

        # be sure to modify the $CHANNEL_NAME variable accordingly

        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble1","blue","35","tom"]}'
        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble2","red","50","tom"]}'
        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble3","blue","70","tom"]}'
        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["transferMarble","marble2","jerry"]}'
        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["transferMarblesBasedOnColor","blue","jerry"]}'
        peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["delete","marble1"]}'

-  If you chose to map the CouchDB ports in docker-compose, you can now view
   the state database through the CouchDB web interface (Fauxton) by opening
   a browser and navigating to the following URL:

   ``http://localhost:5984/_utils``

You should see a database named ``mychannel`` (or your unique channel name) and
the documents inside it.

.. note:: For the below commands, be sure to update the $CHANNEL_NAME variable appropriately.

You can run regular queries from the CLI (e.g. reading ``marble2``):

.. code:: bash

      peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["readMarble","marble2"]}'

The output should display the details of ``marble2``:

.. code:: bash

       Query Result: {"color":"red","docType":"marble","name":"marble2","owner":"jerry","size":50}

You can retrieve the history of a specific marble - e.g. ``marble1``:

.. code:: bash

      peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["getHistoryForMarble","marble1"]}'

The output should display the transactions on ``marble1``:

.. code:: bash

      Query Result: [{"TxId":"1c3d3caf124c89f91a4c0f353723ac736c58155325f02890adebaa15e16e6464", "Value":{"docType":"marble","name":"marble1","color":"blue","size":35,"owner":"tom"}},{"TxId":"755d55c281889eaeebf405586f9e25d71d36eb3d35420af833a20a2f53a3eefd", "Value":{"docType":"marble","name":"marble1","color":"blue","size":35,"owner":"jerry"}},{"TxId":"819451032d813dde6247f85e56a89262555e04f14788ee33e28b232eef36d98f", "Value":}]

You can also perform rich queries on the data content, such as querying marble fields by owner ``jerry``:

.. code:: bash

      peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarblesByOwner","jerry"]}'

The output should display the two marbles owned by ``jerry``:

.. code:: bash

       Query Result: [{"Key":"marble2", "Record":{"color":"red","docType":"marble","name":"marble2","owner":"jerry","size":50}},{"Key":"marble3", "Record":{"color":"blue","docType":"marble","name":"marble3","owner":"jerry","size":70}}]


Why CouchDB
-------------
CouchDB is a kind of NoSQL solution. It is a document-oriented database where document fields are stored as key-value maps. Fields can be either a simple key-value pair, list, or map.
In addition to keyed/composite-key/key-range queries which are supported by LevelDB, CouchDB also supports full data rich queries capability, such as non-key queries against the whole blockchain data,
since its data content is stored in JSON format and fully queryable. Therefore, CouchDB can meet chaincode, auditing, reporting requirements for many use cases that not supported by LevelDB.

CouchDB can also enhance the security for compliance and data protection in the blockchain. As it is able to implement field-level security through the filtering and masking of individual attributes within a transaction, and only authorizing the read-only permission if needed.

In addition, CouchDB falls into the AP-type (Availability and Partition Tolerance) of the CAP theorem. It uses a master-master replication model with ``Eventual Consistency``.
More information can be found on the
`Eventual Consistency page of the CouchDB documentation <http://docs.couchdb.org/en/latest/intro/consistency.html>`__.
However, under each fabric peer, there is no database replicas, writes to database are guaranteed consistent and durable (not ``Eventual Consistency``).

CouchDB is the first external pluggable state database for Fabric, and there could and should be other external database options. For example, IBM enables the relational database for its blockchain.
And the CP-type (Consistency and Partition Tolerance) databases may also in need, so as to enable data consistency without application level guarantee.


A Note on Data Persistence
--------------------------

If data persistence is desired on the peer container or the CouchDB container,
one option is to mount a directory in the docker-host into a relevant directory
in the container. For example, you may add the following two lines in
the peer container specification in the ``docker-compose-base.yaml`` file:

.. code:: bash

       volumes:
        - /var/hyperledger/peer0:/var/hyperledger/production

For the CouchDB container, you may add the following two lines in the CouchDB
container specification:

.. code:: bash

       volumes:
        - /var/hyperledger/couchdb0:/opt/couchdb/data

.. _Troubleshoot:

Troubleshooting
---------------

-  Always start your network fresh.  Use the following command
   to remove artifacts, crypto, containers and chaincode images:

   .. code:: bash

      ./byfn.sh down

   .. note:: You **will** see errors if you do not remove old containers
             and images.

-  If you see Docker errors, first check your docker version (:doc:`prereqs`),
   and then try restarting your Docker process.  Problems with Docker are
   oftentimes not immediately recognizable.  For example, you may see errors
   resulting from an inability to access crypto material mounted within a
   container.

   If they persist remove your images and start from scratch:

   .. code:: bash

       docker rm -f $(docker ps -aq)
       docker rmi -f $(docker images -q)

-  If you see errors on your create, instantiate, invoke or query commands, make
   sure you have properly updated the channel name and chaincode name.  There
   are placeholder values in the supplied sample commands.


-  If you see the below error:

   .. code:: bash

       Error: Error endorsing chaincode: rpc error: code = 2 desc = Error installing chaincode code mycc:1.0(chaincode /var/hyperledger/production/chaincodes/mycc.1.0 exits)

   You likely have chaincode images (e.g. ``dev-peer1.org2.example.com-mycc-1.0`` or
   ``dev-peer0.org1.example.com-mycc-1.0``) from prior runs. Remove them and try
   again.

   .. code:: bash

       docker rmi -f $(docker images | grep peer[0-9]-peer[0-9] | awk '{print $3}')

-  If you see something similar to the following:

   .. code:: bash

      Error connecting: rpc error: code = 14 desc = grpc: RPC failed fast due to transport failure
      Error: rpc error: code = 14 desc = grpc: RPC failed fast due to transport failure

   Make sure you are running your network against the "1.0.0" images that have
   been retagged as "latest".

-  If you see the below error:

   .. code:: bash

     [configtx/tool/localconfig] Load -> CRIT 002 Error reading configuration: Unsupported Config Type ""
     panic: Error reading configuration: Unsupported Config Type ""

   Then you did not set the ``FABRIC_CFG_PATH`` environment variable properly.  The
   configtxgen tool needs this variable in order to locate the configtx.yaml.  Go
   back and execute an ``export FABRIC_CFG_PATH=$PWD``, then recreate your
   channel artifacts.

-  To cleanup the network, use the ``down`` option:

   .. code:: bash

       ./byfn.sh down

-  If you see an error stating that you still have "active endpoints", then prune
   your Docker networks.  This will wipe your previous networks and start you with a
   fresh environment:

   .. code:: bash

        docker network prune

   You will see the following message:

   .. code:: bash

      WARNING! This will remove all networks not used by at least one container.
      Are you sure you want to continue? [y/N]

   Select ``y``.

-  If you see an error similar to the following:

   .. code:: bash

      /bin/bash: ./scripts/script.sh: /bin/bash^M: bad interpreter: No such file or directory

   Ensure that the file in question (**script.sh** in this example) is encoded
   in the Unix format. This was most likely caused by not setting
   ``core.autocrlf`` to ``false`` in your Git configuration (see
   :ref:`windows-extras`). There are several ways of fixing this. If you have
   access to the vim editor for instance, open the file:

   .. code:: bash

      vim ./fabric-samples/first-network/scripts/script.sh

   Then change its format by executing the following vim command:

   .. code:: bash

      :set ff=unix

.. note:: If you continue to see errors, share your logs on the
          **fabric-questions** channel on
          `Hyperledger Rocket Chat <https://chat.hyperledger.org/home>`__
          or on `StackOverflow <https://stackoverflow.com/questions/tagged/hyperledger-fabric>`__.

.. Licensed under Creative Commons Attribution 4.0 International License
   https://creativecommons.org/licenses/by/4.0/
