tendermint/docs/app-dev/abci-cli.md

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Using ABCI-CLI

To facilitate testing and debugging of ABCI servers and simple apps, we built a CLI, the abci-cli, for sending ABCI messages from the command line.

Install

Make sure you have Go installed.

Next, install the abci-cli tool and example applications:

git clone https://github.com/tendermint/tendermint.git
cd tendermint
make install_abci

Now run abci-cli to see the list of commands:

Usage:
  abci-cli [command]

Available Commands:
  batch          Run a batch of abci commands against an application
  check_tx       Validate a tx
  commit         Commit the application state and return the Merkle root hash
  console        Start an interactive abci console for multiple commands
  finalize_block Send a set of transactions to the application
  kvstore        ABCI demo example
  echo           Have the application echo a message
  help           Help about any command
  info           Get some info about the application
  query          Query the application state
  set_option     Set an options on the application

Flags:
      --abci string      socket or grpc (default "socket")
      --address string   address of application socket (default "tcp://127.0.0.1:26658")
  -h, --help             help for abci-cli
  -v, --verbose          print the command and results as if it were a console session

Use "abci-cli [command] --help" for more information about a command.

KVStore - First Example

The abci-cli tool lets us send ABCI messages to our application, to help build and debug them.

The most important messages are finalize_block, check_tx, and commit, but there are others for convenience, configuration, and information purposes.

We'll start a kvstore application, which was installed at the same time as abci-cli above. The kvstore just stores transactions in a merkle tree.

Its code can be found here and looks like:

func cmdKVStore(cmd *cobra.Command, args []string) error {
    logger := log.NewTMLogger(log.NewSyncWriter(os.Stdout))

    // Create the application - in memory or persisted to disk
    var app types.Application
    if flagPersist == "" {
        app = kvstore.NewKVStoreApplication()
    } else {
        app = kvstore.NewPersistentKVStoreApplication(flagPersist)
        app.(*kvstore.PersistentKVStoreApplication).SetLogger(logger.With("module", "kvstore"))
    }

    // Start the listener
    srv, err := server.NewServer(flagAddrD, flagAbci, app)
    if err != nil {
        return err
    }

    // Stop upon receiving SIGTERM or CTRL-C.
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer cancel()

    srv.SetLogger(logger.With("module", "abci-server"))
    if err := srv.Start(ctx); err != nil {
        return err
    }

    // Run until shutdown.
<-ctx.Done()
srv.Wait()
}

Start by running:

abci-cli kvstore

And in another terminal, run

abci-cli echo hello
abci-cli info

You'll see something like:

-> data: hello
-> data.hex: 68656C6C6F

and:

-> data: {"size":0}
-> data.hex: 7B2273697A65223A307D

An ABCI application must provide two things:

• a socket server
• a handler for ABCI messages

When we run the abci-cli tool we open a new connection to the application's socket server, send the given ABCI message, and wait for a response.

The server may be generic for a particular language, and we provide a reference implementation in Golang. See the list of other ABCI implementations for servers in other languages.

The handler is specific to the application, and may be arbitrary, so long as it is deterministic and conforms to the ABCI interface specification.

So when we run abci-cli info, we open a new connection to the ABCI server, which calls the Info() method on the application, which tells us the number of transactions in our Merkle tree.

Now, since every command opens a new connection, we provide the abci-cli console and abci-cli batch commands, to allow multiple ABCI messages to be sent over a single connection.

Running abci-cli console should drop you in an interactive console for speaking ABCI messages to your application.

Try running these commands:

> echo hello
-> code: OK
-> data: hello
-> data.hex: 0x68656C6C6F

> info
-> code: OK
-> data: {"size":0}
-> data.hex: 0x7B2273697A65223A307D

> commit
-> code: OK
-> data.hex: 0x0000000000000000

> finalize_block "abc"
-> code: OK

> info
-> code: OK
-> data: {"size":1}
-> data.hex: 0x7B2273697A65223A317D

> commit
-> code: OK
-> data.hex: 0x0200000000000000

> query "abc"
-> code: OK
-> log: exists
-> height: 2
-> value: abc
-> value.hex: 616263

> finalize_block "def=xyz"
-> code: OK

> commit
-> code: OK
-> data.hex: 0x0400000000000000

> query "def"
-> code: OK
-> log: exists
-> height: 3
-> value: xyz
-> value.hex: 78797A

Note that if we do finalize_block "abc" it will store (abc, abc), but if we do finalize_block "abc=efg" it will store (abc, efg).

Similarly, you could put the commands in a file and run abci-cli --verbose batch < myfile.

Bounties

Want to write an app in your favorite language?! We'd be happy to add you to our ecosystem! See funding opportunities from the Interchain Foundation for implementations in new languages and more.

The abci-cli is designed strictly for testing and debugging. In a real deployment, the role of sending messages is taken by Tendermint, which connects to the app using three separate connections, each with its own pattern of messages.

For examples of running an ABCI app with Tendermint, see the getting started guide. Next is the ABCI specification.