trypipe

Checks state of each function in a pipeline and exits block on error

Description

trypipe checks the state of each function and exits the block if any of them fail. Where trypipe differs from regular try blocks is trypipe will check every process along the pipeline as well as the terminating function (which try only validates against). The downside to this is that piped functions can no longer run in parallel.

Usage

trypipe { code-block } -> <stdout>

<stdin> -> trypipe { -> code-block } -> <stdout>

Examples

trypipe {
    out: "Hello, World!" -> grep: "non-existent string" -> cat
    out: "This command will be ignored"
}

Formated pager (less) where the pager isn't called if the formatter (pretty) fails (eg input isn't valid JSON):

func pless {
    -> trypipe { -> pretty -> less }
}

Detail

A failure is determined by:

• Any process that returns a non-zero exit number
• Any process that returns more output via STDERR than it does via STDOUT

You can see which run mode your functions are executing under via the fid-list command.

See Also

• Schedulers: Overview of the different schedulers (or 'run modes') in Murex
• catch: Handles the exception code raised by try or trypipe
• fid-list: Lists all running functions within the current Murex session
• if: Conditional statement to execute different blocks of code depending on the result of the condition
• runmode: Alter the scheduler's behaviour at higher scoping level
• switch: Blocks of cascading conditionals
• try: Handles errors inside a block of code