Initial version of a declarative fcron

example-deployments/services/processes.nix

@@ -123,7 +123,13 @@ rec {
   };
 
   fcron = {
-    pkg = constructors.fcron {};
+    pkg = constructors.declarativeFcron {
+      fcrontabPerUser = {
+        systab = ''
+          @ 1 echo hello >> /tmp/hello
+        '';
+      };
+    };
 
     requiresUniqueIdsFor = [ "uids" "gids" ];
   };

services-agnostic/constructors.nix

@@ -63,7 +63,12 @@ in
 
   fcron = import ./fcron {
     inherit createManagedProcess stateDir spoolDir runtimeDir tmpDir forceDisableUserChange;
-    inherit (pkgs) writeTextFile fcron;
+    inherit (pkgs) lib writeTextFile fcron;
+  };
+
+  declarativeFcron = import ./fcron/declarative.nix {
+    inherit createManagedProcess stateDir spoolDir runtimeDir tmpDir forceDisableUserChange;
+    inherit (pkgs) lib writeTextFile fcron;
   };
 
   hydra-evaluator = import ./hydra/hydra-evaluator.nix {

services-agnostic/fcron/declarative.nix

@@ -0,0 +1,32 @@
+{createManagedProcess, writeTextFile, lib, fcron, stateDir, runtimeDir, tmpDir, spoolDir, forceDisableUserChange}:
+
+{ instanceSuffix ? ""
+, instanceName ? "fcron${instanceSuffix}"
+, initialize ? ""
+, fcrontabPerUser
+}:
+
+let
+  fcronSpoolDir = "${spoolDir}/${instanceName}";
+in
+import ./default.nix {
+  inherit createManagedProcess writeTextFile lib fcron stateDir runtimeDir tmpDir spoolDir forceDisableUserChange;
+} {
+  inherit instanceSuffix instanceName;
+
+  initialize = ''
+    ${lib.concatMapStrings (user:
+      let
+        fcrontab = builtins.getAttr user fcrontabPerUser;
+        fcrontabFile = writeTextFile {
+          name = "fcrontab-${user}";
+          text = fcrontab;
+        };
+      in
+      ''
+        cp ${fcrontabFile} ${fcronSpoolDir}/${user}.orig
+      ''
+    ) (builtins.attrNames fcrontabPerUser)}
+    ${initialize}
+  '';
+}

services-agnostic/fcron/default.nix

@@ -1,5 +1,5 @@
-{createManagedProcess, writeTextFile, fcron, stateDir, runtimeDir, tmpDir, spoolDir, forceDisableUserChange}:
-{instanceSuffix ? "", instanceName ? "fcron${instanceSuffix}"}:
+{createManagedProcess, writeTextFile, lib, fcron, stateDir, runtimeDir, tmpDir, spoolDir, forceDisableUserChange}:
+{instanceSuffix ? "", instanceName ? "fcron${instanceSuffix}", initialize ? ""}:
 
 let
   fcronSpoolDir = "${spoolDir}/${instanceName}";
@@ -24,11 +24,19 @@ in
 createManagedProcess {
   name = instanceName;
   inherit instanceName;
+
   initialize = ''
-    mkdir -p ${fcronSpoolDir}
+    mkdir -p ${fcronEtcDir}
+    cp ${configFile} ${fcronEtcDir}/fcron.conf
+    chmod 644 ${fcronEtcDir}/fcron.conf
+    ${lib.optionalString (!forceDisableUserChange) ''
+      chown root:${group} ${fcronEtcDir}/fcron.conf
+    ''}
+    ${initialize}
   '';
+
   process = "${fcron}/bin/fcron";
-  args = [ "--configfile" configFile ];
+  args = [ "--configfile" "${fcronEtcDir}/fcron.conf" ];
   foregroundProcessExtraArgs = [ "--foreground" "--nosyslog" ];
   daemonExtraArgs = [ "--background" ];
 
@@ -39,6 +47,8 @@ createManagedProcess {
     users = {
       "${user}" = {
         inherit group;
+        homeDir = fcronSpoolDir;
+        createHomeDir = true;
         description = "Fcron user";
       };
     };