Fix stopping daemons, write preliminary testcases for s6-rc

README.md

@@ -32,6 +32,8 @@ Currently, the following process managers are supported:
 * `systemd`: [systemd](https://www.freedesktop.org/wiki/Software/systemd)
 * `launchd`: [launchd](https://www.launchd.info)
 * `cygrunsrv`: Cygwin's [cygrunsrv](http://web.mit.edu/cygwin/cygwin_v1.3.2/usr/doc/Cygwin/cygrunsrv.README)
+* `s6-rc`: the [s6-rc](https://skarnet.org/software/s6-rc) tool that manages
+  services, using [s6](https://skarnet.org/software/s6) as a supervising process
 
 It can also work with the following solutions that are technically not
 categorized as process managers (but can still be used as such):

examples/services-agnostic/constructors.nix

@@ -109,4 +109,9 @@ in
     inherit createManagedProcess;
     inherit (pkgs) docker kmod;
   };
+
+  s6-svscan = import ./s6-svscan.nix {
+    inherit createManagedProcess runtimeDir;
+    inherit (pkgs) s6;
+  };
 }

examples/services-agnostic/s6-svscan.nix

@@ -0,0 +1,12 @@
+{createManagedProcess, s6, runtimeDir}:
+{instanceSuffix ? "", instanceName ? "s6-svscan${instanceSuffix}", scanDir ? "${runtimeDir}/service${instanceSuffix}"}:
+
+createManagedProcess {
+  name = instanceName;
+  path = [ s6 ];
+  foregroundProcess = "${s6}/bin/s6-svscan";
+  args = [ scanDir ];
+  initialize = ''
+    mkdir -p ${scanDir}
+  '';
+}

nixproc/create-managed-process/s6-rc/generate-s6-service.nix

@@ -127,8 +127,9 @@ else if daemon != null then
         text = ''
           #!${execline}/bin/execlineb -P
 
-          backtick pid { cat ${pidFile} }
-          kill $pid
+          backtick PID { cat ${pidFile} }
+          importas -i PID PID
+          kill $PID
         '';
       };
     };

tests/processes-s6-svscan.nix

@@ -0,0 +1,21 @@
+{ pkgs ? import <nixpkgs> { inherit system; }
+, system ? builtins.currentSystem
+, stateDir ? "/var"
+, runtimeDir ? "${stateDir}/run"
+, logDir ? "${stateDir}/log"
+, cacheDir ? "${stateDir}/cache"
+, tmpDir ? (if stateDir == "/var" then "/tmp" else "${stateDir}/tmp")
+, forceDisableUserChange ? false
+, processManager ? "sysvinit"
+}:
+
+let
+  constructors = import ../examples/services-agnostic/constructors.nix {
+    inherit pkgs stateDir runtimeDir logDir tmpDir cacheDir forceDisableUserChange processManager;
+  };
+in
+rec {
+  s6-svscan = {
+    pkg = constructors.s6-svscan {};
+  };
+}

tests/webapps-agnostic-s6-rc.nix

@@ -0,0 +1,176 @@
+{nixpkgs ? <nixpkgs>}:
+
+with import "${nixpkgs}/nixos/lib/testing-python.nix" { system = builtins.currentSystem; };
+
+let
+  s6-svscanProcessEnv = import ../nixproc/create-managed-process/systemd/build-systemd-env.nix {
+    exprFile = ./processes-s6-svscan.nix;
+  };
+
+  processesEnvForeground = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = ../examples/webapps-agnostic/processes.nix;
+    extraParams = {
+      webappMode = "foreground";
+    };
+  };
+
+  processesEnvDaemon = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = ../examples/webapps-agnostic/processes.nix;
+    extraParams = {
+      webappMode = "daemon";
+    };
+  };
+
+  processesEnvAuto = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = ../examples/webapps-agnostic/processes.nix;
+  };
+
+  processesEnvAutoUnprivileged = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = ../examples/webapps-agnostic/processes.nix;
+    forceDisableUserChange = true;
+  };
+
+  processesEnvAdvanced = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = ../examples/webapps-agnostic/processes-advanced.nix;
+  };
+
+  processesEnvEmpty = import ../nixproc/create-managed-process/s6-rc/build-s6-rc-env.nix {
+    exprFile = null;
+  };
+
+  tools = import ../tools {};
+
+  nix-processmgmt = ./..;
+
+  env = "NIX_PATH=nixpkgs=${nixpkgs} SYSTEMD_TARGET_DIR=/etc/systemd-mutable/system";
+in
+makeTest {
+  machine =
+    {pkgs, ...}:
+
+    {
+      virtualisation.pathsInNixDB = [ pkgs.stdenv ] ++ pkgs.coreutils.all ++ [
+        s6-svscanProcessEnv
+        processesEnvForeground
+        processesEnvDaemon
+        processesEnvAuto
+        processesEnvAutoUnprivileged
+        processesEnvAdvanced
+        processesEnvEmpty
+      ];
+
+      virtualisation.writableStore = true;
+      virtualisation.memorySize = 1024;
+
+      # We can't download any substitutes in a test environment. To make tests
+      # faster, we disable substitutes so that Nix does not waste any time by
+      # attempting to download them.
+      nix.extraOptions = ''
+        substitute = false
+      '';
+
+      environment.systemPackages = [
+        pkgs.stdenv
+        pkgs.s6
+        pkgs.s6-rc
+        pkgs.dysnomia
+        tools.common
+        tools.s6-rc
+        tools.systemd
+      ];
+    };
+
+  testScript = ''
+    def check_nginx_redirection():
+        machine.succeed(
+            "curl --fail -H 'Host: webapp.local' http://localhost:8080 | grep 'listening on port: 5000'"
+        )
+
+
+    def check_system_unavailable():
+        machine.fail("curl --fail http://localhost:8080")
+        machine.fail("pgrep -f '/bin/webapp'")
+
+
+    def check_nginx_multi_instance_redirection():
+        machine.succeed(
+            "curl --fail -H 'Host: webapp1.local' http://localhost:8080 | grep 'listening on port: 5001'"
+        )
+        machine.succeed(
+            "curl --fail -H 'Host: webapp5.local' http://localhost:8081 | grep 'listening on port: 5005'"
+        )
+
+
+    start_all()
+
+    machine.succeed("mkdir -p /etc/systemd-mutable/system")
+
+    # Deploy s6-svscan as a systemd unit
+
+    machine.succeed(
+        "${env} nixproc-systemd-switch ${nix-processmgmt}/tests/processes-s6-svscan.nix"
+    )
+
+    # Deploy the system with foreground webapp processes
+
+    machine.succeed(
+        '${env} nixproc-s6-rc-switch ${nix-processmgmt}/examples/webapps-agnostic/processes.nix --extra-params \'{ "webappMode" = "foreground"; }\'${""}'
+    )
+
+    machine.succeed("sleep 1")
+    machine.succeed("pgrep -u webapp -f '/bin/webapp$'")
+
+    check_nginx_redirection()
+
+    # Deploy the system with daemon webapp processes
+
+    machine.succeed(
+        '${env} nixproc-s6-rc-switch ${nix-processmgmt}/examples/webapps-agnostic/processes.nix --extra-params \'{ "webappMode" = "daemon"; }\'${""}'
+    )
+
+    machine.succeed("sleep 1")
+    machine.succeed("pgrep -u webapp -f '/bin/webapp -D$'")
+
+    check_nginx_redirection()
+
+    # Deploy the entire system in auto mode. Should result in foreground webapp processes
+
+    machine.succeed(
+        "${env} nixproc-s6-rc-switch ${nix-processmgmt}/examples/webapps-agnostic/processes.nix"
+    )
+
+    machine.succeed("sleep 1")
+    machine.succeed("pgrep -u webapp -f '/bin/webapp$'")
+
+    check_nginx_redirection()
+
+    # Deploy the advanced example with multiple instances and see if it works
+
+    machine.succeed(
+        "${env} nixproc-s6-rc-switch ${nix-processmgmt}/examples/webapps-agnostic/processes-advanced.nix"
+    )
+
+    machine.succeed("sleep 1")
+
+    check_nginx_multi_instance_redirection()
+
+    # Deploy an instance without changing user privileges
+
+    machine.succeed(
+        "${env} nixproc-s6-rc-switch ${nix-processmgmt}/examples/webapps-agnostic/processes.nix --force-disable-user-change"
+    )
+
+    machine.succeed("sleep 1")
+    machine.succeed("pgrep -u root -f '/bin/webapp$'")
+
+    check_nginx_redirection()
+
+    # Undeploy the system
+
+    machine.succeed(
+        "${env} nixproc-s6-rc-switch --undeploy"
+    )
+
+    check_system_unavailable()
+  '';
+}