Adding an Org to a Channel
==========================

.. note:: Ensure that you have downloaded the appropriate images and binaries
          as outlined in :doc:`install` and :doc:`prereqs` that conform to the
          version of this documentation (which can be found at the bottom of the
          table of contents to the left). In particular, your version of the
          ``fabric-samples`` folder must include the ``eyfn.sh`` ("Extending
          Your First Network") script and its related scripts.

This tutorial serves as an extension to the :doc:`build_network` (BYFN) tutorial,
and will demonstrate the addition of a new organization -- ``Org3`` -- to the
application channel (``mychannel``) autogenerated by BYFN. It assumes a strong
understanding of BYFN, including the usage and functionality of the aforementioned
utilities.

While we will focus solely on the integration of a new organization here, the same
approach can be adopted when performing other channel configuration updates (updating
modification policies or altering batch size, for example). To learn more about the
process and possibilities of channel config updates in general, check out
:doc:`config_update`). It's also worth noting that channel configuration updates like
the one demonstrated here will usually be the responsibility of an organization admin
(rather than a chaincode or application developer).

.. note:: Make sure the automated ``byfn.sh`` script runs without error on
          your machine before continuing. If you have exported your binaries and
          the related tools (``cryptogen``, ``configtxgen``, etc) into your PATH
          variable, you'll be able to modify the commands accordingly without
          passing the fully qualified path.

Setup the Environment
~~~~~~~~~~~~~~~~~~~~~

We will be operating from the root of the ``first-network`` subdirectory within
your local clone of ``fabric-samples``. Change into that directory now. You will
also want to open a few extra terminals for ease of use.

First, use the ``byfn.sh`` script to tidy up. This command will kill any active
or stale docker containers and remove previously generated artifacts. It is by no
means **necessary** to bring down a Fabric network in order to perform channel
configuration update tasks. However, for the sake of this tutorial, we want to operate
from a known initial state. Therefore let's run the following command to clean up any
previous environments:

.. code:: bash

  ./byfn.sh down

Now generate the default BYFN artifacts:

.. code:: bash

  ./byfn.sh generate

And launch the network making use of the scripted execution within the CLI container:

.. code:: bash

  ./byfn.sh up

Now that you have a clean version of BYFN running on your machine, you have two
different paths you can pursue. First, we offer a fully commented script that will
carry out a config transaction update to bring Org3 into the network.

Also, we will show a "manual" version of the same process, showing each step
and explaining what it accomplishes (since we show you how to bring down your
network before this manual process, you could also run the script and then look at
each step).

Bring Org3 into the Channel with the Script
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You should be in ``first-network``. To use the script, simply issue the following:

.. code:: bash

  ./eyfn.sh up

The output here is well worth reading. You'll see the Org3 crypto material being
added, the config update being created and signed, and then chaincode being installed
to allow Org3 to execute ledger queries.

If everything goes well, you'll get this message:

.. code:: bash

  ========= All GOOD, EYFN test execution completed ===========

``eyfn.sh`` can be used with the same Node.js chaincode and database options
as ``byfn.sh`` by issuing the following (instead of ``./byfn.sh up``):

.. code:: bash

  ./byfn.sh up -c testchannel -s couchdb -l node

And then:

.. code:: bash

  ./eyfn.sh up -c testchannel -s couchdb -l node

For those who want to take a closer look at this process, the rest of the doc will
show you each command for making a channel update and what it does.

Bring Org3 into the Channel Manually
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note:: The manual steps outlined below assume that the ``FABRIC_LOGGING_SPEC``
          in the ``cli`` and ``Org3cli`` containers is set to ``DEBUG``.

          For the ``cli`` container, 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=INFO
                - FABRIC_LOGGING_SPEC=DEBUG

          For the ``Org3cli`` container, you can set this by modifying the
          ``docker-compose-org3.yaml`` file in the ``first-network`` directory.
          e.g.

          .. code::

            Org3cli:
              container_name: Org3cli
              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=INFO
                - FABRIC_LOGGING_SPEC=DEBUG

If you've used the ``eyfn.sh`` script, you'll need to bring your network down.
This can be done by issuing:

.. code:: bash

  ./eyfn.sh down

This will bring down the network, delete all the containers and undo what we've
done to add Org3.

When the network is down, bring it back up again.

.. code:: bash

  ./byfn.sh generate

Then:

.. code:: bash

  ./byfn.sh up

This will bring your network back to the same state it was in before you executed
the ``eyfn.sh`` script.

Now we're ready to add Org3 manually. As a first step, we'll need to generate Org3's
crypto material.

Generate the Org3 Crypto Material
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In another terminal, change into the ``org3-artifacts`` subdirectory from
``first-network``.

.. code:: bash

  cd org3-artifacts

There are two ``yaml`` files of interest here: ``org3-crypto.yaml`` and ``configtx.yaml``.
First, generate the crypto material for Org3:

.. code:: bash

  ../../bin/cryptogen generate --config=./org3-crypto.yaml

This command reads in our new crypto ``yaml`` file -- ``org3-crypto.yaml`` -- and
leverages ``cryptogen`` to generate the keys and certificates for an Org3
CA as well as two peers bound to this new Org. As with the BYFN implementation,
this crypto material is put into a newly generated ``crypto-config`` folder
within the present working directory (in our case, ``org3-artifacts``).

Now use the ``configtxgen`` utility to print out the Org3-specific configuration
material in JSON. We will preface the command by telling the tool to look in the
current directory for the ``configtx.yaml`` file that it needs to ingest.

.. code:: bash

    export FABRIC_CFG_PATH=$PWD && ../../bin/configtxgen -printOrg Org3MSP > ../channel-artifacts/org3.json

The above command creates a JSON file -- ``org3.json`` -- and outputs it into the
``channel-artifacts`` subdirectory at the root of ``first-network``. This
file contains the policy definitions for Org3, as well as three important certificates
presented in base 64 format: the admin user certificate (which will be needed to act as
the admin of Org3 later on), a CA root cert, and a TLS root cert. In an upcoming step we
will append this JSON file to the channel configuration.

Our final piece of housekeeping is to port the Orderer Org's MSP material into
the Org3 ``crypto-config`` directory. In particular, we are concerned with the
Orderer's TLS root cert, which will allow for secure communication between
Org3 entities and the network's ordering node.

.. code:: bash

  cd ../ && cp -r crypto-config/ordererOrganizations org3-artifacts/crypto-config/

Now we're ready to update the channel configuration...

Prepare the CLI Environment
~~~~~~~~~~~~~~~~~~~~~~~~~~~

The update process makes use of the configuration translator tool -- ``configtxlator``.
This tool provides a stateless REST API independent of the SDK. Additionally it
provides a CLI, to simplify configuration tasks in Fabric networks. The tool allows
for the easy conversion between different equivalent data representations/formats
(in this case, between protobufs and JSON). Additionally, the tool can compute a
configuration update transaction based on the differences between two channel
configurations.

First, exec into the CLI container. Recall that this container has been
mounted with the BYFN ``crypto-config`` library, giving us access to the MSP material
for the two original peer organizations and the Orderer Org. The bootstrapped
identity is the Org1 admin user, meaning that any steps where we want to act as
Org2 will require the export of MSP-specific environment variables.

.. code:: bash

  docker exec -it cli bash

Export the ``ORDERER_CA`` and ``CHANNEL_NAME`` variables:

.. code:: bash

  export ORDERER_CA=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem  && export CHANNEL_NAME=mychannel

Check to make sure the variables have been properly set:

.. code:: bash

  echo $ORDERER_CA && echo $CHANNEL_NAME

.. note:: If for any reason you need to restart the CLI container, you will also need to
          re-export the two environment variables -- ``ORDERER_CA`` and ``CHANNEL_NAME``.

Fetch the Configuration
~~~~~~~~~~~~~~~~~~~~~~~

Now we have a CLI container with our two key environment variables -- ``ORDERER_CA``
and ``CHANNEL_NAME`` exported.  Let's go fetch the most recent config block for the
channel -- ``mychannel``.

The reason why we have to pull the latest version of the config is because channel
config elements are versioned. Versioning is important for several reasons. It prevents
config changes from being repeated or replayed (for instance, reverting to a channel config
with old CRLs would represent a security risk). Also it helps ensure concurrency (if you
want to remove an Org from your channel, for example, after a new Org has been added,
versioning will help prevent you from removing both Orgs, instead of just the Org you want
to remove).

.. code:: bash

  peer channel fetch config config_block.pb -o orderer.example.com:7050 -c $CHANNEL_NAME --tls --cafile $ORDERER_CA

This command saves the binary protobuf channel configuration block to
``config_block.pb``. Note that the choice of name and file extension is arbitrary.
However, following a convention which identifies both the type of object being
represented and its encoding (protobuf or JSON) is recommended.

When you issued the ``peer channel fetch`` command, there was a decent amount of
output in the terminal. The last line in the logs is of interest:

.. code:: bash

  2017-11-07 17:17:57.383 UTC [channelCmd] readBlock -> DEBU 011 Received block: 2

This is telling us that the most recent configuration block for ``mychannel`` is
actually block 2, **NOT** the genesis block. By default, the ``peer channel fetch config``
command returns the most **recent** configuration block for the targeted channel, which
in this case is the third block. This is because the BYFN script defined anchor
peers for our two organizations -- ``Org1`` and ``Org2`` -- in two separate channel update
transactions.

As a result, we have the following configuration sequence:

  * block 0: genesis block
  * block 1: Org1 anchor peer update
  * block 2: Org2 anchor peer update

Convert the Configuration to JSON and Trim It Down
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Now we will make use of the ``configtxlator`` tool to decode this channel
configuration block into JSON format (which can be read and modified by humans).
We also must strip away all of the headers, metadata, creator signatures, and
so on that are irrelevant to the change we want to make. We accomplish this by
means of the ``jq`` tool:

.. code:: bash

  configtxlator proto_decode --input config_block.pb --type common.Block | jq .data.data[0].payload.data.config > config.json

This leaves us with a trimmed down JSON object -- ``config.json``, located in
the ``fabric-samples`` folder inside ``first-network`` -- which
will serve as the baseline for our config update.

Take a moment to open this file inside your text editor of choice (or in your
browser). Even after you're done with this tutorial, it will be worth studying it
as it reveals the underlying configuration structure and the other kind of channel
updates that can be made. We discuss them in more detail in :doc:`config_update`.

Add the Org3 Crypto Material
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note:: The steps you've taken up to this point will be nearly identical no matter
          what kind of config update you're trying to make. We've chosen to add an
          org with this tutorial because it's one of the most complex channel
          configuration updates you can attempt.

We'll use the ``jq`` tool once more to append the Org3 configuration definition
-- ``org3.json`` -- to the channel's application groups field, and name the output
-- ``modified_config.json``.

.. code:: bash

  jq -s '.[0] * {"channel_group":{"groups":{"Application":{"groups": {"Org3MSP":.[1]}}}}}' config.json ./channel-artifacts/org3.json > modified_config.json

Now, within the CLI container we have two JSON files of interest -- ``config.json``
and ``modified_config.json``. The initial file contains only Org1 and Org2 material,
whereas "modified" file contains all three Orgs. At this point it's simply
a matter of re-encoding these two JSON files and calculating the delta.

First, translate ``config.json`` back into a protobuf called ``config.pb``:

.. code:: bash

  configtxlator proto_encode --input config.json --type common.Config --output config.pb

Next, encode ``modified_config.json`` to ``modified_config.pb``:

.. code:: bash

  configtxlator proto_encode --input modified_config.json --type common.Config --output modified_config.pb

Now use ``configtxlator`` to calculate the delta between these two config
protobufs. This command will output a new protobuf binary named ``org3_update.pb``:

.. code:: bash

  configtxlator compute_update --channel_id $CHANNEL_NAME --original config.pb --updated modified_config.pb --output org3_update.pb

This new proto -- ``org3_update.pb`` -- contains the Org3 definitions and high
level pointers to the Org1 and Org2 material. We are able to forgo the extensive
MSP material and modification policy information for Org1 and Org2 because this
data is already present within the channel's genesis block. As such, we only need
the delta between the two configurations.

Before submitting the channel update, we need to perform a few final steps. First,
let's decode this object into editable JSON format and call it ``org3_update.json``:

.. code:: bash

  configtxlator proto_decode --input org3_update.pb --type common.ConfigUpdate | jq . > org3_update.json

Now, we have a decoded update file -- ``org3_update.json`` -- that we need to wrap
in an envelope message. This step will give us back the header field that we stripped away
earlier. We'll name this file ``org3_update_in_envelope.json``:

.. code:: bash

  echo '{"payload":{"header":{"channel_header":{"channel_id":"'$CHANNEL_NAME'", "type":2}},"data":{"config_update":'$(cat org3_update.json)'}}}' | jq . > org3_update_in_envelope.json

Using our properly formed JSON -- ``org3_update_in_envelope.json`` -- we will
leverage the ``configtxlator`` tool one last time and convert it into the
fully fledged protobuf format that Fabric requires. We'll name our final update
object ``org3_update_in_envelope.pb``:

.. code:: bash

  configtxlator proto_encode --input org3_update_in_envelope.json --type common.Envelope --output org3_update_in_envelope.pb

Sign and Submit the Config Update
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Almost done!

We now have a protobuf binary -- ``org3_update_in_envelope.pb`` -- within
our CLI container. However, we need signatures from the requisite Admin users
before the config can be written to the ledger. The modification policy (mod_policy)
for our channel Application group is set to the default of "MAJORITY", which means that
we need a majority of existing org admins to sign it. Because we have only two orgs --
Org1 and Org2 -- and the majority of two is two, we need both of them to sign. Without
both signatures, the ordering service will reject the transaction for failing to
fulfill the policy.

First, let's sign this update proto as the Org1 Admin. Remember that the CLI container
is bootstrapped with the Org1 MSP material, so we simply need to issue the
``peer channel signconfigtx`` command:

.. code:: bash

  peer channel signconfigtx -f org3_update_in_envelope.pb

The final step is to switch the CLI container's identity to reflect the Org2 Admin
user. We do this by exporting four environment variables specific to the Org2 MSP.

.. note:: Switching between organizations to sign a config transaction (or to do anything
          else) is not reflective of a real-world Fabric operation. A single container
          would never be mounted with an entire network's crypto material. Rather, the
          config update would need to be securely passed out-of-band to an Org2
          Admin for inspection and approval.

Export the Org2 environment variables:

.. code:: bash

  # you can issue all of these commands at once

  export CORE_PEER_LOCALMSPID="Org2MSP"

  export 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

  export CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp

  export CORE_PEER_ADDRESS=peer0.org2.example.com:9051

Lastly, we will issue the ``peer channel update`` command. The Org2 Admin signature
will be attached to this call so there is no need to manually sign the protobuf a
second time:

.. note:: The upcoming update call to the ordering service will undergo a series
          of systematic signature and policy checks. As such you may find it
          useful to stream and inspect the ordering node's logs. From another shell,
          issue a ``docker logs -f orderer.example.com`` command to display them.

Send the update call:

.. code:: bash

  peer channel update -f org3_update_in_envelope.pb -c $CHANNEL_NAME -o orderer.example.com:7050 --tls --cafile $ORDERER_CA

You should see a message digest indication similar to the following if your
update has been submitted successfully:

.. code:: bash

  2018-02-24 18:56:33.499 UTC [msp/identity] Sign -> DEBU 00f Sign: digest: 3207B24E40DE2FAB87A2E42BC004FEAA1E6FDCA42977CB78C64F05A88E556ABA

You will also see the submission of our configuration transaction:

.. code:: bash

  2018-02-24 18:56:33.499 UTC [channelCmd] update -> INFO 010 Successfully submitted channel update

The successful channel update call returns a new block -- block 5 -- to all of the
peers on the channel. If you remember, blocks 0-2 are the initial channel
configurations while blocks 3 and 4 are the instantiation and invocation of
the ``mycc`` chaincode. As such, block 5 serves as the most recent channel
configuration with Org3 now defined on the channel.

Inspect the logs for ``peer0.org1.example.com``:

.. code:: bash

      docker logs -f peer0.org1.example.com

Follow the demonstrated process to fetch and decode the new config block if you wish to inspect
its contents.

Configuring Leader Election
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note:: This section is included as a general reference for understanding
          the leader election settings when adding organizations to a network
          after the initial channel configuration has completed. This sample
          defaults to dynamic leader election, which is set for all peers in the
          network in `peer-base.yaml`.

Newly joining peers are bootstrapped with the genesis block, which does not
contain information about the organization that is being added in the channel
configuration update. Therefore new peers are not able to utilize gossip as
they cannot verify blocks forwarded by other peers from their own organization
until they get the configuration transaction which added the organization to the
channel. Newly added peers must therefore have one of the following
configurations so that they receive blocks from the ordering service:

1. To utilize static leader mode, configure the peer to be an organization
leader:

::

    CORE_PEER_GOSSIP_USELEADERELECTION=false
    CORE_PEER_GOSSIP_ORGLEADER=true


.. note:: This configuration must be the same for all new peers added to the
          channel.

2. To utilize dynamic leader election, configure the peer to use leader
election:

::

    CORE_PEER_GOSSIP_USELEADERELECTION=true
    CORE_PEER_GOSSIP_ORGLEADER=false


.. note:: Because peers of the newly added organization won't be able to form
          membership view, this option will be similar to the static
          configuration, as each peer will start proclaiming itself to be a
          leader. However, once they get updated with the configuration
          transaction that adds the organization to the channel, there will be
          only one active leader for the organization. Therefore, it is
          recommended to leverage this option if you eventually want the
          organization's peers to utilize leader election.


Join Org3 to the Channel
~~~~~~~~~~~~~~~~~~~~~~~~

At this point, the channel configuration has been updated to include our new
organization -- ``Org3`` -- meaning that peers attached to it can now join ``mychannel``.

First, let's launch the containers for the Org3 peers and an Org3-specific CLI.

Open a new terminal and from ``first-network`` kick off the Org3 docker compose:

.. code:: bash

  docker-compose -f docker-compose-org3.yaml up -d

This new compose file has been configured to bridge across our initial network,
so the two peers and the CLI container will be able to resolve with the existing
peers and ordering node. With the three new containers now running, exec into
the Org3-specific CLI container:

.. code:: bash

  docker exec -it Org3cli bash

Just as we did with the initial CLI container, export the two key environment
variables: ``ORDERER_CA`` and ``CHANNEL_NAME``:

.. code:: bash

  export ORDERER_CA=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem && export CHANNEL_NAME=mychannel

Check to make sure the variables have been properly set:

.. code:: bash

  echo $ORDERER_CA && echo $CHANNEL_NAME

Now let's send a call to the ordering service asking for the genesis block of
``mychannel``. The ordering service is able to verify the Org3 signature
attached to this call as a result of our successful channel update. If Org3
has not been successfully appended to the channel config, the ordering
service should reject this request.

.. note:: Again, you may find it useful to stream the ordering node's logs
          to reveal the sign/verify logic and policy checks.

Use the ``peer channel fetch`` command to retrieve this block:

.. code:: bash

  peer channel fetch 0 mychannel.block -o orderer.example.com:7050 -c $CHANNEL_NAME --tls --cafile $ORDERER_CA

Notice, that we are passing a ``0`` to indicate that we want the first block on
the channel's ledger (i.e. the genesis block). If we simply passed the
``peer channel fetch config`` command, then we would have received block 5 -- the
updated config with Org3 defined. However, we can't begin our ledger with a
downstream block -- we must start with block 0.

Issue the ``peer channel join`` command and pass in the genesis block -- ``mychannel.block``:

.. code:: bash

  peer channel join -b mychannel.block

If you want to join the second peer for Org3, export the ``TLS`` and ``ADDRESS`` variables
and reissue the ``peer channel join command``:

.. code:: bash

  export CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org3.example.com/peers/peer1.org3.example.com/tls/ca.crt && export CORE_PEER_ADDRESS=peer1.org3.example.com:12051

  peer channel join -b mychannel.block

.. _upgrade-and-invoke:

Upgrade and Invoke Chaincode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The final piece of the puzzle is to increment the chaincode version and update
the endorsement policy to include Org3. Since we know that an upgrade is coming,
we can forgo the futile exercise of installing version 1 of the chaincode. We
are solely concerned with the new version where Org3 will be part of the
endorsement policy, therefore we'll jump directly to version 2 of the chaincode.

From the Org3 CLI:

.. code:: bash

  peer chaincode install -n mycc -v 2.0 -p github.com/chaincode/chaincode_example02/go/

Modify the environment variables accordingly and reissue the command if you want to
install the chaincode on the second peer of Org3. Note that a second installation is
not mandated, as you only need to install chaincode on peers that are going to serve as
endorsers or otherwise interface with the ledger (i.e. query only). Peers will
still run the validation logic and serve as committers without a running chaincode
container.

Now jump back to the **original** CLI container and install the new version on the
Org1 and Org2 peers. We submitted the channel update call with the Org2 admin
identity, so the container is still acting on behalf of ``peer0.org2``:

.. code:: bash

  peer chaincode install -n mycc -v 2.0 -p github.com/chaincode/chaincode_example02/go/

Flip to the ``peer0.org1`` identity:

.. code:: bash

  export CORE_PEER_LOCALMSPID="Org1MSP"

  export 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

  export CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp

  export CORE_PEER_ADDRESS=peer0.org1.example.com:7051

And install again:

.. code:: bash

  peer chaincode install -n mycc -v 2.0 -p github.com/chaincode/chaincode_example02/go/

Now we're ready to upgrade the chaincode. There have been no modifications to
the underlying source code, we are simply adding Org3 to the endorsement policy for
a chaincode -- ``mycc`` -- on ``mychannel``.

.. note:: Any identity satisfying the chaincode's instantiation policy can issue
          the upgrade call. By default, these identities are the channel Admins.

Send the call:

.. code:: bash

  peer chaincode upgrade -o orderer.example.com:7050 --tls $CORE_PEER_TLS_ENABLED --cafile $ORDERER_CA -C $CHANNEL_NAME -n mycc -v 2.0 -c '{"Args":["init","a","90","b","210"]}' -P "OR ('Org1MSP.peer','Org2MSP.peer','Org3MSP.peer')"

You can see in the above command that we are specifying our new version by means
of the ``v`` flag. You can also see that the endorsement policy has been modified to
``-P "OR ('Org1MSP.peer','Org2MSP.peer','Org3MSP.peer')"``, reflecting the
addition of Org3 to the policy. The final area of interest is our constructor
request (specified with the ``c`` flag).

As with an instantiate call, a chaincode upgrade requires usage of the ``init``
method. **If** your chaincode requires arguments be passed to the ``init`` method,
then you will need to do so here.

The upgrade call adds a new block -- block 6 -- to the channel's ledger and allows
for the Org3 peers to execute transactions during the endorsement phase. Hop
back to the Org3 CLI container and issue a query for the value of ``a``. This will
take a bit of time because a chaincode image needs to be built for the targeted peer,
and the container needs to start:

.. code:: bash

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

We should see a response of ``Query Result: 90``.

Now issue an invocation to move ``10`` from ``a`` to ``b``:

.. code:: bash

    peer chaincode invoke -o orderer.example.com:7050  --tls $CORE_PEER_TLS_ENABLED --cafile $ORDERER_CA -C $CHANNEL_NAME -n mycc -c '{"Args":["invoke","a","b","10"]}'

Query one final time:

.. code:: bash

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

We should see a response of ``Query Result: 80``, accurately reflecting the
update of this chaincode's world state.

Conclusion
~~~~~~~~~~

The channel configuration update process is indeed quite involved, but there is a
logical method to the various steps. The endgame is to form a delta transaction object
represented in protobuf binary format and then acquire the requisite number of admin
signatures such that the channel configuration update transaction fulfills the channel's
modification policy.

The ``configtxlator`` and ``jq`` tools, along with the ever-growing ``peer channel``
commands, provide us with the functionality to accomplish this task.

Updating the Channel Config to include an Org3 Anchor Peer (Optional)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The Org3 peers were able to establish gossip connection to the Org1 and Org2
peers since Org1 and Org2 had anchor peers defined in the channel configuration.
Likewise newly added organizations like Org3 should also define their anchor peers
in the channel configuration so that any new peers from other organizations can
directly discover an Org3 peer.

Continuing from the Org3 CLI, we will make a channel configuration update to
define an Org3 anchor peer. The process will be similar to the previous
configuration update, therefore we'll go faster this time.

As before, we will fetch the latest channel configuration to get started.
Inside the CLI container for Org3 fetch the most recent config block for the channel,
using the ``peer channel fetch`` command.

.. code:: bash

  peer channel fetch config config_block.pb -o orderer.example.com:7050 -c $CHANNEL_NAME --tls --cafile $ORDERER_CA

After fetching the config block we will want to convert it into JSON format. To do
this we will use the configtxlator tool, as done previously when adding Org3 to the
channel. When converting it we need to remove all the headers, metadata, and signatures
that are not required to update Org3 to include an anchor peer by using the jq
tool. This information will be reincorporated later before we proceed to update the
channel configuration.

.. code:: bash

    configtxlator proto_decode --input config_block.pb --type common.Block | jq .data.data[0].payload.data.config > config.json

The ``config.json`` is the now trimmed JSON representing the latest channel configuration
that we will update.

Using the jq tool again, we will update the configuration JSON with the Org3 anchor peer we
want to add.

.. code:: bash

    jq '.channel_group.groups.Application.groups.Org3MSP.values += {"AnchorPeers":{"mod_policy": "Admins","value":{"anchor_peers": [{"host": "peer0.org3.example.com","port": 11051}]},"version": "0"}}' config.json > modified_anchor_config.json

We now have two JSON files, one for the current channel configuration,
``config.json``, and one for the desired channel configuration ``modified_anchor_config.json``.
Next we convert each of these back into protobuf format and calculate the delta between the two.

Translate ``config.json`` back into protobuf format as ``config.pb``

.. code:: bash

    configtxlator proto_encode --input config.json --type common.Config --output config.pb

Translate the ``modified_anchor_config.json`` into protobuf format as ``modified_anchor_config.pb``

.. code:: bash

    configtxlator proto_encode --input modified_anchor_config.json --type common.Config --output modified_anchor_config.pb

Calculate the delta between the two protobuf formatted configurations.

.. code:: bash

    configtxlator compute_update --channel_id $CHANNEL_NAME --original config.pb --updated modified_anchor_config.pb --output anchor_update.pb

Now that we have the desired update to the channel we must wrap it in an envelope
message so that it can be properly read. To do this we must first convert the protobuf
back into a JSON that can be wrapped.

We will use the configtxlator command again to convert ``anchor_update.pb`` into ``anchor_update.json``

.. code:: bash

    configtxlator proto_decode --input anchor_update.pb --type common.ConfigUpdate | jq . > anchor_update.json

Next we will wrap the update in an envelope message, restoring the previously
stripped away header, outputting it to ``anchor_update_in_envelope.json``

.. code:: bash

    echo '{"payload":{"header":{"channel_header":{"channel_id":"'$CHANNEL_NAME'", "type":2}},"data":{"config_update":'$(cat anchor_update.json)'}}}' | jq . > anchor_update_in_envelope.json

Now that we have reincorporated the envelope we need to convert it
to a protobuf so it can be properly signed and submitted to the orderer for the update.

.. code:: bash

    configtxlator proto_encode --input anchor_update_in_envelope.json --type common.Envelope --output anchor_update_in_envelope.pb

Now that the update has been properly formatted it is time to sign off and submit it. Since this
is only an update to Org3 we only need to have Org3 sign off on the update. As we are
in the Org3 CLI container there is no need to switch the CLI containers identity, as it is
already using the Org3 identity. Therefore we can just use the ``peer channel update`` command
as it will also sign off on the update as the Org3 admin before submitting it to the orderer.

.. code:: bash

    peer channel update -f anchor_update_in_envelope.pb -c $CHANNEL_NAME -o orderer.example.com:7050 --tls --cafile $ORDERER_CA

The orderer receives the config update request and cuts a block with the updated configuration.
As peers receive the block, they will process the configuration updates.

Inspect the logs for one of the peers. While processing the configuration transaction from the new block,
you will see gossip re-establish connections using the new anchor peer for Org3. This is proof
that the configuration update has been successfully applied!

.. code:: bash

    docker logs -f peer0.org1.example.com

.. code:: bash

    2019-06-12 17:08:57.924 UTC [gossip.gossip] learnAnchorPeers -> INFO 89a Learning about the configured anchor peers of Org1MSP for channel mychannel : [{peer0.org1.example.com 7051}]
    2019-06-12 17:08:57.926 UTC [gossip.gossip] learnAnchorPeers -> INFO 89b Learning about the configured anchor peers of Org2MSP for channel mychannel : [{peer0.org2.example.com 9051}]
    2019-06-12 17:08:57.926 UTC [gossip.gossip] learnAnchorPeers -> INFO 89c Learning about the configured anchor peers of Org3MSP for channel mychannel : [{peer0.org3.example.com 11051}]

Congratulations, you have now made two configuration updates --- one to add Org3 to the channel,
and a second to define an anchor peer for Org3.

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