Child Processes

Child Processes

A child process inherits the process environment, which does not hold the loaded values. Variables.apply gives a Std.Process launch every key the load applied:

module Ex07Child

import Std.Io as Io
import Std.Process as Process
import PuduLangEnvironment.Loader as Loader
import PuduLangEnvironment.Options as Options
import PuduLangEnvironment.Source as Source
import PuduLangEnvironment.Variables as Variables

export fn main() -> Int {
  let options = Options.defaults().withSources(&[Source.Text("example", "GREETING=hello\nTARGET=world\n")])
  match Loader.load(&options) {
    case Ok(variables) => {
      let plan = Variables.apply(&variables, &Process.launch("sh", &["-c", "echo \"$GREETING, $TARGET\""]).isolated())
      match Process.runLaunch(&plan, "") {
        case Ok(finished) => {
          let _shown = Io.writeLine(finished.output.trim())
          0
        }
        case Err(_) => 1
      }
    }
    case Err(_) => 1
  }
}

Output:

hello, world

isolated() keeps the rest of the program's environment from the child; without it the child inherits the process environment and receives the applied keys over it.

Related

• Variables And Secrets