Synit: depend-on initialization scripts

nixproc/backends/synit/create-synit-daemon.nix

@@ -1,7 +1,9 @@
-{ lib, writeTextFile, toPreserves }:
+{ lib, runtimeShell, toPreserves, writeScript, writeTextFile }:
 
 { name, description, argv, environment, directory
-# List of services that this configuration depends on.
+# Shell instructions that specify how the state of the process should be initialized.
+, initialize ? ""
+  # List of services that this configuration depends on.
 , dependencies ? [ ]
   # Daemon will not be started until all elements of depends-on are asserted.
   # Example: [ "<service-state <milestone network> up>" ]
@@ -39,6 +41,21 @@ in writeTextFile {
       <depends-on ${serviceName} ${pkg.serviceName}>
     '') dependencies)
 
+    + (lib.strings.optionalString (initialize != "") (let
+      # TODO: depend the initialization on other dependencies?
+      initializeName = "initialize-${name}";
+      script = writeScript "${initializeName}.sh" ''
+        #!${runtimeShell}
+        ${initialize}
+      '';
+    in ''
+      <depends-on ${serviceName} <service-state <daemon ${initializeName}> complete>>
+      <deamon ${initializeName} {
+        argv: [ "${script}" ]
+        restart: on-error
+      }>
+    ''))
+
     + ''
       <daemon ${name} ${toPreserves processSpec}>
     '';

nixproc/backends/synit/default.nix

@@ -1,4 +1,4 @@
-{ lib, undaemonize, writeTextFile }:
+{ lib, runtimeShell, writeScript, writeTextFile, undaemonize }:
 
 rec {
   util = import ./util.nix { inherit lib; };
@@ -6,7 +6,7 @@ rec {
   toPreserves = util.toPreserves { };
 
   createSynitDaemon = import ../../backends/synit/create-synit-daemon.nix {
-    inherit lib writeTextFile;
+    inherit lib runtimeShell writeScript writeTextFile;
     inherit toPreserves;
   };
 

nixproc/backends/synit/generate-synit-service.nix

@@ -6,7 +6,7 @@
 
 let
   generatedTargetSpecificArgs = {
-    inherit name description environment directory dependencies;
+    inherit name description environment directory dependencies initialize;
 
     argv = if foregroundProcess != null then
       [ foregroundProcess ] ++ foregroundProcessArgs

nixproc/create-managed-process/universal/create-managed-process-universal.nix

@@ -115,7 +115,7 @@ let
   };
 
   synit = import ../../backends/synit {
-    inherit (pkgs) lib undaemonize writeTextFile;
+    inherit (pkgs) lib runtimeShell undaemonize writeScript writeTextFile;
   };
 
 in