runBlock

Execute a closure, recording the result value in the journal. The result value will be re-played in case of re-invocation (e.g. because of failure recovery or suspension point) without re-executing the closure.

You can name this closure using the name parameter. This name will be available in the observability tools.

The closure should tolerate retries, that is Restate might re-execute the closure multiple times until it records a result. To control and limit the amount of retries, pass a [RetryPolicy] to this function.

Error handling

Errors occurring within this closure won't be propagated to the caller, unless they are TerminalException. Consider the following code:

// Bad usage of try-catch outside the runBlock
try {
    ctx.runBlock {
        throw IllegalStateException();
    };
} catch (e: IllegalStateException) {
    // This will never be executed,
    // but the error will be retried by Restate,
    // following the invocation retry policy.
}

// Good usage of try-catch outside the runBlock
try {
    ctx.runBlock {
        throw TerminalException("my error");
    };
} catch (e: TerminalException) {
    // This is invoked
}

To propagate failures to the run call-site, make sure to wrap them in TerminalException.

Parameters