Exec component

Q: How do I fail the route when the command fails?

Set exitValues=0. Any other exit code then fails the exchange with ExecException.

The exec component runs a local program or script from a route, writes the message body to its standard input and returns its standard output as the new body.

Scheme: exec: · Crate: cameleer-core · Cargo feature: none, always included (build features) · Consumer: no · Producer: yes · Apache Camel: Exec

When to use it

Call an existing command-line tool or script from an integration (convert a file, run a diagnostic).
On an edge gateway, read device state with a local command (vcgencmd, nvidia-smi, df) on a timer.
Let an AI agent route run a fixed, allow-listed command as a tool. Keep the executable fixed in the route; never build it from model output.

URI format

text

exec:executable[?options]

Example

yaml example: exec-tool-version

- route:
    id: record-tool-version
    from:
      uri: timer:version
      parameters:
        repeatCount: 1
        delay: 0
      steps:
        - to: exec:git?args=--version&timeout=5000
        - log: "exit ${header.CamelExecExitValue}: ${body}"
        - to: log:versions

At startup the route runs git --version once; the body becomes the output, such as git version 2.47.0.

Rust DSL

rust

use cameleer_core::prelude::*;

pub fn routes(ctx: &CamelContext) -> Result<()> {
    ctx.add_routes(|b| {
        b.from("timer:version?repeatCount=1&delay=0")
            .route_id("record-tool-version")
            .to("exec:git?args=--version&timeout=5000")
            .log("exit ${header.CamelExecExitValue}: ${body}")
            .to("log:versions");
    })
}

Options

option	default	description
`args`		Arguments, separated by spaces. Quote an argument that contains spaces with `"`.
`workingDir`	current directory	Directory to run the program in.
`timeout`	none	Kill the program and fail with `ExecException` after this many ms.
`outFile`		Use the content of this file as the result instead of standard output.
`useStderrOnEmptyStdout`	`false`	Use standard error as the body when standard output is empty.
`exitValues`	any	Comma separated list of accepted exit codes; any other code fails with `ExecException`.
`binding`, `commandExecutor`, `commandLogLevel`, `lazyStartProducer`		Accepted and ignored.

Message headers

header	direction	description
`CamelExecCommandExecutable`	in	Overrides the executable.
`CamelExecCommandArgs`	in	Overrides `args` (a string or a list).
`CamelExecCommandWorkingDir`	in	Overrides `workingDir`.
`CamelExecCommandTimeout`	in	Overrides `timeout` (ms).
`CamelExecCommandOutFile`	in	Overrides `outFile`.
`CamelExecUseStderrOnEmptyStdout`	in	Overrides `useStderrOnEmptyStdout`.
`CamelExecExitValue`	out	The exit code.
`CamelExecStderr`	out	Standard error output.

Run it with Docker

docker run --rm -v "$PWD:/routes:ro" pmsudhi/cameleer run /routes/version.camel.yaml

The program must exist inside the container. The image is minimal, so build your own image FROM pmsudhi/cameleer with the tools you need.

Common questions

Does exec use a shell?

No. The program is started directly with its arguments, so pipes and * do not work. To use them, run exec:sh?args=-c "your | pipeline" explicitly.

How do I fail the route when the command fails?

Set exitValues=0. Any other exit code then fails the exchange with ExecException.

Is the message body passed to the program?

Yes. A non-null body is written to standard input.

Found a problem?

If something on this page doesn't match what Cameleer does, or you hit a bug while building with it, please help fix it, whether you are a person or a coding agent: open an issue that describes what you saw, then fork the repository, fix it, add or update a test, run cargo test --workspace, and open a pull request. CONTRIBUTING.md explains the ground rules.