peer channel

The peer channel command allows administrators to perform channel related operations on a peer, such as joining a channel or listing the channels to which a peer is joined.

Syntax

The peer channel command has the following subcommands:

  • create
  • fetch
  • getinfo
  • join
  • list
  • signconfigtx
  • update

peer channel

Operate a channel: create|fetch|join|list|update|signconfigtx|getinfo.

Usage:
  peer channel [command]

Available Commands:
  create       Create a channel
  fetch        Fetch a block
  getinfo      get blockchain information of a specified channel.
  join         Joins the peer to a channel.
  list         List of channels peer has joined.
  signconfigtx Signs a configtx update.
  update       Send a configtx update.

Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
  -h, --help                                help for channel
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

Use "peer channel [command] --help" for more information about a command.

peer channel create

Create a channel and write the genesis block to a file.

Usage:
  peer channel create [flags]

Flags:
  -c, --channelID string     In case of a newChain command, the channel ID to create. It must be all lower case, less than 250 characters long and match the regular expression: [a-z][a-z0-9.-]*
  -f, --file string          Configuration transaction file generated by a tool such as configtxgen for submitting to orderer
  -h, --help                 help for create
      --outputBlock string   The path to write the genesis block for the channel. (default ./<channelID>.block)
  -t, --timeout duration     Channel creation timeout (default 10s)

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel fetch

Fetch a specified block, writing it to a file.

Usage:
  peer channel fetch <newest|oldest|config|(number)> [outputfile] [flags]

Flags:
      --bestEffort         Whether fetch requests should ignore errors and return blocks on a best effort basis
  -c, --channelID string   In case of a newChain command, the channel ID to create. It must be all lower case, less than 250 characters long and match the regular expression: [a-z][a-z0-9.-]*
  -h, --help               help for fetch

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel getinfo

get blockchain information of a specified channel. Requires '-c'.

Usage:
  peer channel getinfo [flags]

Flags:
  -c, --channelID string   In case of a newChain command, the channel ID to create. It must be all lower case, less than 250 characters long and match the regular expression: [a-z][a-z0-9.-]*
  -h, --help               help for getinfo

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel join

Joins the peer to a channel.

Usage:
  peer channel join [flags]

Flags:
  -b, --blockpath string   Path to file containing genesis block
  -h, --help               help for join

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel list

List of channels peer has joined.

Usage:
  peer channel list [flags]

Flags:
  -h, --help   help for list

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel signconfigtx

Signs the supplied configtx update file in place on the filesystem. Requires '-f'.

Usage:
  peer channel signconfigtx [flags]

Flags:
  -f, --file string   Configuration transaction file generated by a tool such as configtxgen for submitting to orderer
  -h, --help          help for signconfigtx

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

peer channel update

Signs and sends the supplied configtx update file to the channel. Requires '-f', '-o', '-c'.

Usage:
  peer channel update [flags]

Flags:
  -c, --channelID string   In case of a newChain command, the channel ID to create. It must be all lower case, less than 250 characters long and match the regular expression: [a-z][a-z0-9.-]*
  -f, --file string        Configuration transaction file generated by a tool such as configtxgen for submitting to orderer
  -h, --help               help for update

Global Flags:
      --cafile string                       Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
      --certfile string                     Path to file containing PEM-encoded X509 public key to use for mutual TLS communication with the orderer endpoint
      --clientauth                          Use mutual TLS when communicating with the orderer endpoint
      --connTimeout duration                Timeout for client to connect (default 3s)
      --keyfile string                      Path to file containing PEM-encoded private key to use for mutual TLS communication with the orderer endpoint
  -o, --orderer string                      Ordering service endpoint
      --ordererTLSHostnameOverride string   The hostname override to use when validating the TLS connection to the orderer.
      --tls                                 Use TLS when communicating with the orderer endpoint

Example Usage

peer channel create examples

Here’s an example that uses the --orderer global flag on the peer channel create command.

  • Create a sample channel mychannel defined by the configuration transaction contained in file ./createchannel.txn. Use the orderer at orderer.example.com:7050.

    peer channel create -c mychannel -f ./createchannel.txn --orderer orderer.example.com:7050
    
    2018-02-25 08:23:57.548 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    2018-02-25 08:23:57.626 UTC [channelCmd] InitCmdFactory -> INFO 019 Endorser and orderer connections initialized
    2018-02-25 08:23:57.834 UTC [channelCmd] readBlock -> INFO 020 Received block: 0
    2018-02-25 08:23:57.835 UTC [main] main -> INFO 021 Exiting.....
    

    Block 0 is returned indicating that the channel has been successfully created.

Here’s an example of the peer channel create command option.

  • Create a new channel mychannel for the network, using the orderer at ip address orderer.example.com:7050. The configuration update transaction required to create this channel is defined the file ./createchannel.txn. Wait 30 seconds for the channel to be created.

      peer channel create -c mychannel --orderer orderer.example.com:7050 -f ./createchannel.txn -t 30s
    
      2018-02-23 06:31:58.568 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
      2018-02-23 06:31:58.669 UTC [channelCmd] InitCmdFactory -> INFO 019 Endorser and orderer connections initialized
      2018-02-23 06:31:58.877 UTC [channelCmd] readBlock -> INFO 020 Received block: 0
      2018-02-23 06:31:58.878 UTC [main] main -> INFO 021 Exiting.....
    
      ls -l
    
      -rw-r--r-- 1 root root 11982 Feb 25 12:24 mychannel.block
    

    You can see that channel mychannel has been successfully created, as indicated in the output where block 0 (zero) is added to the blockchain for this channel and returned to the peer, where it is stored in the local directory as mychannel.block.

    Block zero is often called the genesis block as it provides the starting configuration for the channel. All subsequent updates to the channel will be captured as configuration blocks on the channel’s blockchain, each of which supersedes the previous configuration.

peer channel fetch example

Here’s some examples of the peer channel fetch command.

  • Using the newest option to retrieve the most recent channel block, and store it in the file mychannel.block.

    peer channel fetch newest mychannel.block -c mychannel --orderer orderer.example.com:7050
    
    2018-02-25 13:10:16.137 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    2018-02-25 13:10:16.144 UTC [channelCmd] readBlock -> INFO 00a Received block: 32
    2018-02-25 13:10:16.145 UTC [main] main -> INFO 00b Exiting.....
    
    ls -l
    
    -rw-r--r-- 1 root root 11982 Feb 25 13:10 mychannel.block
    

    You can see that the retrieved block is number 32, and that the information has been written to the file mychannel.block.

  • Using the (block number) option to retrieve a specific block – in this case, block number 16 – and store it in the default block file.

    peer channel fetch 16  -c mychannel --orderer orderer.example.com:7050
    
    2018-02-25 13:46:50.296 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    2018-02-25 13:46:50.302 UTC [channelCmd] readBlock -> INFO 00a Received block: 16
    2018-02-25 13:46:50.302 UTC [main] main -> INFO 00b Exiting.....
    
    ls -l
    
    -rw-r--r-- 1 root root 11982 Feb 25 13:10 mychannel.block
    -rw-r--r-- 1 root root  4783 Feb 25 13:46 mychannel_16.block
    

    You can see that the retrieved block is number 16, and that the information has been written to the default file mychannel_16.block.

    For configuration blocks, the block file can be decoded using the configtxlator command. See this command for an example of decoded output. User transaction blocks can also be decoded, but a user program must be written to do this.

peer channel getinfo example

Here’s an example of the peer channel getinfo command.

  • Get information about the local peer for channel mychannel.

    peer channel getinfo -c mychannel
    
    2018-02-25 15:15:44.135 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    Blockchain info: {"height":5,"currentBlockHash":"JgK9lcaPUNmFb5Mp1qe1SVMsx3o/22Ct4+n5tejcXCw=","previousBlockHash":"f8lZXoAn3gF86zrFq7L1DzW2aKuabH9Ow6SIE5Y04a4="}
    2018-02-25 15:15:44.139 UTC [main] main -> INFO 006 Exiting.....
    

    You can see that the latest block for channel mychannel is block 5. You can also see the cryptographic hashes for the most recent blocks in the channel’s blockchain.

peer channel join example

Here’s an example of the peer channel join command.

  • Join a peer to the channel defined in the genesis block identified by the file ./mychannel.genesis.block. In this example, the channel block was previously retrieved by the peer channel fetch command.

    peer channel join -b ./mychannel.genesis.block
    
    2018-02-25 12:25:26.511 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    2018-02-25 12:25:26.571 UTC [channelCmd] executeJoin -> INFO 006 Successfully submitted proposal to join channel
    2018-02-25 12:25:26.571 UTC [main] main -> INFO 007 Exiting.....
    

    You can see that the peer has successfully made a request to join the channel.

peer channel list example

Here’s an example of the peer channel list command.

  • List the channels to which a peer is joined.

    peer channel list
    
    2018-02-25 14:21:20.361 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    Channels peers has joined:
    mychannel
    2018-02-25 14:21:20.372 UTC [main] main -> INFO 006 Exiting.....
    

    You can see that the peer is joined to channel mychannel.

peer channel signconfigtx example

Here’s an example of the peer channel signconfigtx command.

  • Sign the channel update transaction defined in the file ./updatechannel.txn. The example lists the configuration transaction file before and after the command.

    ls -l
    
    -rw-r--r--  1 anthonyodowd  staff   284 25 Feb 18:16 updatechannel.tx
    
    peer channel signconfigtx -f updatechannel.tx
    
    2018-02-25 18:16:44.456 GMT [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
    2018-02-25 18:16:44.459 GMT [main] main -> INFO 002 Exiting.....
    
    ls -l
    
    -rw-r--r--  1 anthonyodowd  staff  2180 25 Feb 18:16 updatechannel.tx
    

    You can see that the peer has successfully signed the configuration transaction by the increase in the size of the file updatechannel.tx from 284 bytes to 2180 bytes.

peer channel update example

Here’s an example of the peer channel update command.

  • Update the channel mychannel using the configuration transaction defined in the file ./updatechannel.txn. Use the orderer at ip address orderer.example.com:7050 to send the configuration transaction to all peers in the channel to update their copy of the channel configuration.

    peer channel update -c mychannel -f ./updatechannel.txn -o orderer.example.com:7050
    
    2018-02-23 06:32:11.569 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
    2018-02-23 06:32:11.626 UTC [main] main -> INFO 010 Exiting.....
    

    At this point, the channel mychannel has been successfully updated.

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