Development-Network

Prerequisites

• docker-compose
• docker-IO
• access to a linux machine

Windows Troubleshooting:

• make sure your OS is up-to-date (e.g. build ~19041 or later; see Windows 10 Update Assistent etc.)
• make sure your docker installation is up-to-date (e.g. version ~19.0.8 or later)
• make sure your docker-compose installation is up-to-date (e.g. version ~1.25 or later)
• if you get the error shadowJar x... during chaincode compilation, try $ git config --global core.autocrlf false and re-cloning the repository
• if you get the startup orderer error: make sure "WSL2" (Windows Subsystem for Linux) is installed

This seems to fix the issues for under Windows for us. Please let us know if you still run into issues.

Generating the channel-description and the genesis-block

The network will read the genesis block ./orderer.block and the channel description ./myc.tx which have to be generated before starting the network. They are determined by the ./scripts/resources/configtx.yaml. To create these files you have to execute the script ./scripts/createChannelTx.sh, which needs to be done on a linux system since it executes the linux-binary ./scripts/resources/configtx.

Starting the Network

To start the development network simply clone the repository, execute

$ ./startNetwork.sh

and wait for the network to start. Do not wait for the console ouput to stop! Once the network outputs

############################################################################################
#                                   CHAINCODE INITIALIZED                                  #
#                                     READY FOR ACTION                                     #
############################################################################################

it has succesfully started. This may take a few minutes.

Alternatively, you can start the network by executing

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

Note that in this case you have to remove the containers manually before restarting the network.

Starting the network starts an orderer (orderer), a peer (peer), a chaincode container (chaincode), a couchdb container (couchdb), and a command-line-interface container (cli).

• chaincode is the container compiling and running the chaincode for the peer. For that, a build.gradle is required in the chaincode java-project.
• couchdb is used internally to store the ledger state. You probably do not have to worry about this.
• cli provides fabric binaries that can be utilized to do all sorts of stuff to the network manually (e.g. query chaincode, add channels, etc.)

Query/Invoke Manually

Once the network is up, chaincode can be manually queried/invoked by executing

$ docker exec -it cli bash

which opens a shell inside the cli container, from which fabrics binaries can be used as usual, e.g.

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

calls the queryAll transaction inside the mycc chaincode on channel myc,

$ peer chaincode invoke -n mycc -c '{"Args":["transactionName","arg1","arg2","arg3"]}' -C myc

calls the transactionName transactioninside the mycc chaincode on channel myc with arguments arg1,arg2,arg3. You can also use the --transient flag to pass data via the transient data field (see example below). The chaincode does currently not need to be initialized/installed, as the development-network does that during it's setup (./startNetwork.sh) for you.

WARNING: If you want to pass json as a string argument to a transaction, you must put a \" instead of every " in the inner json, e.g.

$ peer chaincode invoke -n mycc -c '{"Args":["transactionName","{\"attribute\": \"value\"}"]}' -C myc

Example chaincode invocation:

$ peer chaincode invoke -n mycc -c '{"Args":["addCourse","{ \"courseId\": \"course1\",\"courseName\": \"courseName1\",\"courseType\": \"Lecture\",\"startDate\": \"2020-06-29\",\"endDate\": \"2020-06-29\",\"ects\": 3,\"lecturerId\": \"lecturer1\",\"maxParticipants\": 100,\"currentParticipants\": 0,\"courseLanguage\": \"English\",\"courseDescription\": \"some lecture\" }"]}' -C myc

Example chaincode invocation utilizing transient data:

$ export VALUE=$(echo -n "{\"matriculationId\":\"0000001\",\"firstName\":\"firstName1\",\"lastName\":\"lastName1\",\"birthDate\":\"1900-07-21\",\"matriculationStatus\":[{\"fieldOfStudy\":\"Computer Science\",\"semesters\":[\"SS2020\"]}]}" | base64 | tr -d \\n)
$ peer chaincode invoke -n mycc -c '{"Args":["addMatriculationData"]}' --transient "{\"0\":\"$VALUE\"}" -C myc

Chaincode and Channel Name

myc and mycc are the names given to the channel and the chaincode respectively by default. The channel name can be adjusted by setting the variable CHAINCODE_NAME in

./scripts/variables.sh

The channel name can currently not be changed, unless you are familiar with hyperledger's configtx tool etc.

Ports

• the peer is reachable under localhost:7051
• the orderer is reachable under localhost:7050

When listing URLs in connection profiles, make sure to add the right protocol (e.g. grpc://localhost:7051). The development network does not support grpc over TLS.

WARNING: Once the production network is up, grpcs should be used!