Link a child job to its parent

A tool that starts other tools can link their jobs to its own, so a reader shows them as children. The link is one environment variable, PITO_JOB_ID, which the child’s start reads and stores as parent.

In the parent

child_env returns the variables a child process needs. Set them on the command; the crate never changes the current process’s environment:

let job = pito_jobs::start("render", None, "trailer-01");
let mut command = std::process::Command::new("encode");
for (key, value) in job.child_env() {
    command.env(key, value);
}
let status = command.status()?;

For the job above, child_env returns:

[("PITO_JOB_ID", "desk:223115:1792004530252")]

When the parent was started with PITO_INVOKER set, the list also carries PITO_INVOKER, so the child records the same invoker.

In the child

Nothing to do: the child calls pito_jobs::start as usual, and its record carries "parent":"desk:223115:1792004530252". A reader groups records by parent to draw the tree.

Who started it

PITO_INVOKER names who started the tool, such as a person, a script or an agent, and is stored as invoker. Set it in the environment of the first tool; child_env passes it on.