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, and a “solo” ordering service.

Install prerequisites

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

You will also need to download and install the Hyperledger Fabric Samples. 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.

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 comprised of 4 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 and instantiate chaincode and drive execution of transactions against the deployed chaincode.

Here’s the help text for the byfn.sh script:

./byfn.sh --help
Usage:
byfn.sh -m up|down|restart|generate [-c <channel name>] [-t <timeout>] [-d <delay>] [-f <docker-compose-file>] [-s <dbtype>]
byfn.sh -h|--help (print this message)
  -m <mode> - one of 'up', 'down', 'restart' or 'generate'
    - '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
  -c <channel name> - channel name to use (defaults to "mychannel")
  -t <timeout> - CLI timeout duration in seconds (defaults to 10000)
  -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) or node

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

      byfn.sh -m generate -c mychannel
      byfn.sh -m up -c mychannel -s couchdb

If you choose not to supply a channel name, then the script will use a default name of mychannel. The CLI timeout parameter (specified with the -t flag) is an optional value; if you choose not to set it, then your CLI container will exit after the default setting of 10000 seconds.

Generate Network Artifacts

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

./byfn.sh -m generate

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

Generating certs and genesis block for with channel 'mychannel' and CLI timeout of '10000'
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 Channel.

Bring Up the Network

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

./byfn.sh -m 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 chaincode. If you’d like to run through this tutorial with node chaincode, pass the following command instead:

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

./byfn.sh -m up -l node

Note

View the Hyperledger Fabric Shim documentation for more info on the node.js chaincode shim APIs.

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

Starting with channel 'mychannel' and CLI timeout of '10000'
Continue (y/n)?y
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:

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 on PEER3 on channel 'mychannel' is successful =====================

===================== 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 Troubleshooting 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:

./byfn.sh -m down

Once again, you will be prompted to continue, respond with a y:

Stopping with channel 'mychannel' and CLI timeout of '10000'
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.

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 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 right now. If you’re interested, you can peruse these topics on your own time.

Before running the tool, let’s take a quick look at a snippet from the crypto-config.yaml. Pay specific attention to the “Name”, “Domain” and “Specs” parameters under the OrdererOrgs header:

OrdererOrgs:
#---------------------------------------------------------
# Orderer
# --------------------------------------------------------
- Name: Orderer
  Domain: example.com
  CA:
      Country: US
      Province: California
      Locality: San Francisco
  #   OrganizationalUnit: Hyperledger Fabric
  #   StreetAddress: address for org # default nil
  #   PostalCode: postalCode for org # default nil
  # ------------------------------------------------------
  # "Specs" - See PeerOrgs below for complete description
# -----------------------------------------------------
  Specs:
    - Hostname: orderer
# -------------------------------------------------------
# "PeerOrgs" - Definition of organizations managing peer nodes
# ------------------------------------------------------
PeerOrgs:
# -----------------------------------------------------
# Org1
# ----------------------------------------------------
- Name: Org1
  Domain: org1.example.com

The naming convention for a network entity is as follows - “{{.Hostname}}.{{.Domain}}”. So using our ordering node as a reference point, we are left with an ordering node named - orderer.example.com that is tied to an MSP ID of Orderer. This file contains extensive documentation on the definitions and syntax. You can also refer to the Membership Service Providers (MSP) documentation for a deeper dive on MSP.

After we run the cryptogen tool, the generated certificates and keys will be saved to a folder titled crypto-config.

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 Channel Configuration (configtxgen) for a complete description of this tool’s functionality.

The orderer block is the Genesis Block for the ordering service, and the channel configuration transaction file is broadcast to the orderer at Channel creation time. The anchor peer transactions, as the name might suggest, specify each Org’s 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 top of this file. You will notice that we have two unique headers. One for the orderer genesis block - TwoOrgsOrdererGenesis - and one for our channel - TwoOrgsChannel.

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.

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

You should see the following in your terminal:

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:

export FABRIC_CFG_PATH=$PWD

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

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

You should see an output similar to the following in your terminal:

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.

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:

# 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

You should see an ouput similar to the following in your terminal:

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:

../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:

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

Start the network

We will leverage a docker-compose 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.

Note

Before launching the network, open the docker-compose-cli.yaml file and comment out the script.sh in the CLI container. Your docker-compose should be modified to look like this:

working_dir: /opt/gopath/src/github.com/hyperledger/fabric/peer
# command: /bin/bash -c './scripts/script.sh ${CHANNEL_NAME}; sleep $TIMEOUT'
volumes

If left uncommented, that script will exercise all of the CLI commands when the network is started, as we describe in the What’s happening behind the scenes? section. However, we want to go through the commands manually in order to expose the syntax and functionality of each call.

The CLI timeout defaults to 10000 seconds. If you need the container available for longer, you can overwrite this setting by passing in a value for the TIMEOUT environment variable.

Start your network:

# if you need the CLI accessible beyond 10000 seconds, pass in TIMEOUT=<your_desired_value>
# after the CHANNEL_NAME variable

CHANNEL_NAME=$CHANNEL_NAME 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.

Environment variables

For the following CLI commands against peer0.org1.example.com 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, then you will need to provide these values accordingly. Inspect the docker-compose-base.yaml for the specific paths:

# 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

Create & Join Channel

Recall that we created the channel configuration transaction using the configtxgen tool in the Create a Channel Configuration Transaction 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:

docker exec -it cli bash

If successful you should see the following:

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

Next, we are going to pass in the generated channel configuration transaction artifact that we created in the Create a Channel Configuration Transaction 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:

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 $CORE_PEER_TLS_ENABLED --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-ID.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.

# By default, this joins ``peer0.org1.example.com`` only
# the <channel-ID.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 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:

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:7051 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

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:

peer channel update -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/Org1MSPanchors.tx --tls $CORE_PEER_TLS_ENABLED --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.

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:7051 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 $CORE_PEER_TLS_ENABLED --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 Chaincode for Developers 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 or Node.js chaincode onto one of the four peer nodes. 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

# this installs the Go chaincode
peer chaincode install -n mycc -v 1.0 -p github.com/chaincode_example02/go/

Node.js

# this installs the Node.js chaincode
# make note of the -l flag; we use this to specify the language
peer chaincode install -n mycc -v 1.0 -l node -p /opt/gopath/src/github.com/chaincode_example02/node/

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 "OR ('Org0MSP.member','Org1MSP.member')". This means that we need “endorsement” from a peer belonging to Org1 OR Org2 (i.e. only one endorsement). If we changed the syntax to AND then we would need two endorsements.

Golang

# 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 $CORE_PEER_TLS_ENABLED --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 "OR ('Org1MSP.member','Org2MSP.member')"

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.

# 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 $CORE_PEER_TLS_ENABLED --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 "OR ('Org1MSP.member','Org2MSP.member')"

See the endorsement policies 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:

# 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:

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

peer chaincode invoke -o orderer.example.com:7050  --tls $CORE_PEER_TLS_ENABLED --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 -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 reveal 90. The syntax for query is as follows.

# 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:

Query Result: 90

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

What’s happening behind the scenes?

Note

These steps describe the scenario in which script.sh is not commented out in the docker-compose-cli.yaml file. Clean your network with ./byfn.sh -m 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 peer0.org2.example.com. 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 "OR    ('Org1MSP.member','Org2MSP.member')", meaning that any transaction must be endorsed by a peer tied to Org1 or Org2.
  • A query against the value of “a” is issued to peer0.org1.example.com. The chaincode was previously installed on peer0.org1.example.com, so this will start a container for Org1 peer0 by the name of dev-peer0.org1.example.com-mycc-1.0. The result of the query is also 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 to move “10” from “a” to “b”
  • The chaincode is then 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.

docker logs -f cli

You should see the following output:

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 on PEER3 on channel 'mychannel' is successful =====================

===================== 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:

$ 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 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:

CHANNEL_NAME=$CHANNEL_NAME TIMEOUT=<pick_a_value> 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 Create & Join Channel 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:
# be sure to modify the $CHANNEL_NAME variable accordingly for the instantiate command

peer chaincode install -n marbles -v 1.0 -p github.com/hyperledger/fabric/examples/chaincode/go/marbles02
peer chaincode instantiate -o orderer.example.com:7050 --tls $CORE_PEER_TLS_ENABLED --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 ('Org0MSP.member','Org1MSP.member')"
  • Create some marbles and move them around:
# be sure to modify the $CHANNEL_NAME variable accordingly

peer chaincode invoke -o orderer.example.com:7050 --tls $CORE_PEER_TLS_ENABLED --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 $CORE_PEER_TLS_ENABLED --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 $CORE_PEER_TLS_ENABLED --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 $CORE_PEER_TLS_ENABLED --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 $CORE_PEER_TLS_ENABLED --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 $CORE_PEER_TLS_ENABLED --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):

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

The output should display the details of marble2:

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

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

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

The output should display the transactions on marble1:

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:

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

The output should display the two marbles owned by jerry:

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 mpas. 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. 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:

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

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

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

Troubleshooting

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

    ./byfn.sh -m 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 (Prerequisites), 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:

    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:

    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.

    docker rmi -f $(docker images | grep peer[0-9]-peer[0-9] | awk '{print $3}')
    
  • If you see something similar to the following:

    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:

    [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:

    ./byfn.sh -m 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:

    docker network prune
    

    You will see the following message:

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

    Select y.

Note

If you continue to see errors, share your logs on the fabric-questions channel on Hyperledger Rocket Chat or on StackOverflow.