daemonize_workflow.ml

#use "topfind"
#thread
#require "ketrew"

let run_command_with_daemonize ~cmd ~email =
  let module KEDSL = Ketrew.EDSL in
  (* Where to run stuff: *)
  let host = KEDSL.Host.tmp_on_localhost in
  (* A node that Ketrew will activate after cmd completes,
     on its success or failure. *)
  let email_target ~success =
    let msg_string = if success then "succeeded" else "failed" in
    let e_program =
      KEDSL.Program.shf "echo \"'%s' %s\" | mail -s \"Status update\" %s"
        cmd msg_string
        email
    in
    let e_process =
      KEDSL.daemonize ~using:`Python_daemon ~host e_program in
    KEDSL.workflow_node KEDSL.without_product
      ~name:("email result " ^ msg_string)
      ~make:e_process
  in
  (* The function `KEDSL.workflow_node` creates a node in the workflow graph.
     The value `KEDSL.without_product` means this node does not
     “produce” anything, it is like a `.PHONY` target in `make`. *)
  KEDSL.workflow_node KEDSL.without_product
    ~name:"daemonized command with email notification"
    ~make:(
      (* A “program” is a datastructure representing an “extended shell script”. *)
      let program = KEDSL.Program.sh cmd in
      KEDSL.daemonize ~host ~using:`Python_daemon program
    )
    ~edges:[
      KEDSL.on_success_activate (email_target true);
      KEDSL.on_failure_activate (email_target false);
    ]

let () =
  (* Grab the command line arguments. *)
  let cmd   = Sys.argv.(1) in
  let email = Sys.argv.(2) in
  (* Create the  workflow with the first argument of the command line: *)
  let workflow = run_command_with_daemonize ~cmd ~email in
  (* Then, `Client.submit_workflow` is the only function that “does”
     something, it submits the constructed workflow to the engine: *)
  Ketrew.Client.submit_workflow workflow