Catches

The error handling mechanism allows recovery when a step encounters an error.

Step-Level Catches

Steps define error handling via catches, which is a list of Step objects:

steps:
    - id: step1
      uses: acts.core.irq
      params:
        key: act1
      catches:
        # Match specific error code
        - uses: acts.core.msg
          if: $ecode() == 'err1'
          params:
            key: catch_err1

        # Match all unhandled errors
        - uses: acts.core.msg
          params:
            key: catch_others

Error Handling Flow

1. An activity in a step triggers an error (via EventAction::Error or acts.core.action)
2. The engine checks the catches list conditions in order
3. Executes the corresponding handler when the first matching catch is found
4. After handling, the step continues normal execution
5. If no catch matches, the error propagates upward

Error Code

Error codes are passed via ecode:

#![allow(unused)]
fn main() {
let mut options = Vars::new();
options.set("ecode", "err1");
rt.do_action2(&pid, &tid, EventAction::Error, options).unwrap();
}

Use $ecode() in the catch if condition to get the error code.