Using dev mode
==============

Normally chaincodes are started and maintained by peer. However in “dev
mode", chaincode is built and started by the user. This mode is useful
during chaincode development phase for rapid code/build/run/debug cycle
turnaround.

We start "dev mode" by leveraging pre-generated orderer and channel artifacts for
a sample dev network.  As such, the user can immediately jump into the process
of compiling chaincode and driving calls.

Install Fabric Samples
----------------------

If you haven't already done so, please install the `Hyperledger Fabric Samples <https://hyperledger-fabric.readthedocs.io/en/release-1.1/samples.html>`_.

Navigate to the ``chaincode-docker-devmode`` directory of the ``fabric-samples``
clone:

.. code:: bash

  cd chaincode-docker-devmode

Download docker images
^^^^^^^^^^^^^^^^^^^^^^

We need four docker images in order for "dev mode" to run against the supplied
docker compose script.  If you installed the ``fabric-samples`` repo clone and
followed the instructions to `download-platform-specific-binaries <http://hyperledger-fabric.readthedocs.io/en/latest/samples.html#download-platform-specific-binaries>`_, then
you should have the necessary Docker images installed locally.

Hyperledger Fabric does not provide 'latest' tag for the docker images (see `FAB-8338 <https://jira.hyperledger.org/browse/FAB-8338>`_ for reference), which means that one has to specify tag explicitly when pulling the images.

This repository provides default tag via `docker-compose environment variables <https://docs.docker.com/compose/environment-variables/>`_. 
The default tag is specified in the `.env <.env>`_ file.

If you want to use different tag either update `.env <.env>`_ file, or override the TAG variable while running docker-compose. 

.. code:: bash

  TAG=1.1.0-pre docker-compose -f docker-compose-simple.yaml up

.. note:: If you retrieved the images through the `download-platform-specific-binaries <http://hyperledger-fabric.readthedocs.io/en/latest/samples.html#download-platform-specific-binaries>`_,
          then you will see additional images listed.  However, we are only concerned with
          these four.

Now 

Terminal 1 - Start the network
------------------------------
Open three terminals and navigate to your ``chaincode-docker-devmode``
directory in each.

.. code:: bash

    docker-compose -f docker-compose-simple.yaml up

The above starts the network with the ``SingleSampleMSPSolo`` orderer profile and
launches the peer in "dev mode".  It also launches two additional containers -
one for the chaincode environment and a CLI to interact with the chaincode.  The
commands for create and join channel are embedded in the CLI container, so we
can jump immediately to the chaincode calls.

Terminal 2 - Build & start the chaincode
----------------------------------------

.. code:: bash

  docker exec -it chaincode bash

You should see the following:

.. code:: bash

  root@d2629980e76b:/opt/gopath/src/chaincode#

Now, compile your chaincode:

.. code:: bash

  cd chaincode_example02/go
  go build -o chaincode_example02

Now run the chaincode:

.. code:: bash

  CORE_CHAINCODE_ID_NAME=mycc:0 ./chaincode_example02

The chaincode is started with peer and chaincode logs indicating successful registration with the peer.
Note that at this stage the chaincode is not associated with any channel. This is done in subsequent steps
using the ``instantiate`` command.

Terminal 3 - Use the chaincode
------------------------------

Even though you are in ``--peer-chaincodedev`` mode, you still have to install the
chaincode so the life-cycle system chaincode can go through its checks normally.
This requirement may be removed in future when in ``--peer-chaincodedev`` mode.

We'll leverage the CLI container to drive these calls.

.. code:: bash

  docker exec -it cli bash

.. code:: bash

  peer chaincode install -p chaincodedev/chaincode/chaincode_example02/go -n mycc -v 0
  peer chaincode instantiate -n mycc -v 0 -c '{"Args":["init","a","100","b","200"]}' -C myc

Now issue an invoke to move ``10`` from ``a`` to ``b``.

.. code:: bash

  peer chaincode invoke -n mycc -c '{"Args":["invoke","a","b","10"]}' -C myc

Finally, query ``a``.  We should see a value of ``90``.

.. code:: bash

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

Testing new chaincode
---------------------

By default, we mount only ``chaincode_example02``.  However, you can easily test different
chaincodes by adding them to the ``chaincode`` subdirectory and relaunching
your network.  At this point they will be accessible in your ``chaincode`` container.

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