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.

If you haven't already done so, please install the :doc:`samples`.

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

cd chaincode-docker-devmode

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 :ref:`download-platform-specific-binaries`, then you should have the necessary Docker images installed locally.

Issue a docker images command to reveal your local Docker Registry. You should see something similar to following:

docker images
REPOSITORY                     TAG                                  IMAGE ID            CREATED             SIZE
hyperledger/fabric-tools       latest                               e09f38f8928d        4 hours ago         1.32 GB
hyperledger/fabric-tools       x86_64-1.0.0-rc1-snapshot-f20846c6   e09f38f8928d        4 hours ago         1.32 GB
hyperledger/fabric-orderer     latest                               0df93ba35a25        4 hours ago         179 MB
hyperledger/fabric-orderer     x86_64-1.0.0-rc1-snapshot-f20846c6   0df93ba35a25        4 hours ago         179 MB
hyperledger/fabric-peer        latest                               533aec3f5a01        4 hours ago         182 MB
hyperledger/fabric-peer        x86_64-1.0.0-rc1-snapshot-f20846c6   533aec3f5a01        4 hours ago         182 MB
hyperledger/fabric-ccenv       latest                               4b70698a71d3        4 hours ago         1.29 GB
hyperledger/fabric-ccenv       x86_64-1.0.0-rc1-snapshot-f20846c6   4b70698a71d3        4 hours ago         1.29 GB

Now open three terminals and navigate to your chaincode-docker-devmode directory in each.

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.

docker exec -it chaincode bash

You should see the following:

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

Now, compile your chaincode:

cd chaincode_example02
go build

Now run the chaincode:

CORE_PEER_ADDRESS=peer:7051 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.

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.

docker exec -it cli bash

peer chaincode install -p chaincodedev/chaincode/chaincode_example02 -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.

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

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

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

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.