Add support for service's to configure working directory (#245)

This adds support for a "working-dir" option in the layered service
configuration, for starting a service in a specified working directory
(the default is still to start it in Pebble's working directory).

Fixes #158

README.md

@@ -523,6 +523,10 @@ services:
         # group and group-id are specified, the group's GID must match group-id.
         group-id: <gid>
 
+        # (Optional) Working directory to run command in. By default, the
+        # command is run in the service manager's current directory.
+        working-dir: <directory>
+
         # (Optional) Defines what happens when the service exits with a zero
         # exit code. Possible values are: "restart" (default) which restarts
         # the service after the backoff delay, "shutdown" which shuts down and
@@ -653,7 +657,8 @@ checks:
             # match group-id.
             group-id: <gid>
 
-            # (Optional) Working directory to run command in.
+            # (Optional) Working directory to run command in. By default, the
+            # command is run in the service manager's current directory.
             working-dir: <directory>
 ```
 

internals/overlord/servstate/handlers.go

@@ -347,6 +347,8 @@ func (s *serviceData) startInternal() error {
 		environment[k] = v
 	}
 
+	s.cmd.Dir = s.config.WorkingDir
+
 	// Start as another user if specified in plan.
 	uid, gid, err := osutil.NormalizeUidGid(s.config.UserID, s.config.GroupID, s.config.User, s.config.Group)
 	if err != nil {

internals/overlord/servstate/manager_test.go

@@ -1763,3 +1763,62 @@ type fakeLogManager struct{}
 func (f fakeLogManager) ServiceStarted(serviceName string, logs *servicelog.RingBuffer) {
 	// no-op
 }
+
+func (s *S) TestNoWorkingDir(c *C) {
+	// Service command should run in current directory (package directory)
+	// if "working-dir" config option not set.
+	dir := c.MkDir()
+	err := os.Mkdir(filepath.Join(dir, "layers"), 0755)
+	c.Assert(err, IsNil)
+	manager, err := servstate.NewManager(s.st, s.runner, dir, nil, nil, fakeLogManager{})
+	c.Assert(err, IsNil)
+	defer manager.Stop()
+
+	outputPath := filepath.Join(dir, "output")
+	layer := parseLayer(c, 0, "layer", fmt.Sprintf(`
+services:
+    nowrkdir:
+        override: replace
+        command: /bin/sh -c "pwd >%s; sleep %g"
+`, outputPath, shortOkayDelay.Seconds()+0.01))
+	err = manager.AppendLayer(layer)
+	c.Assert(err, IsNil)
+
+	chg := s.startServices(c, []string{"nowrkdir"}, 1)
+	s.st.Lock()
+	c.Assert(chg.Err(), IsNil)
+	s.st.Unlock()
+
+	output, err := ioutil.ReadFile(outputPath)
+	c.Assert(err, IsNil)
+	c.Check(string(output), Matches, ".*/overlord/servstate\n")
+}
+
+func (s *S) TestWorkingDir(c *C) {
+	dir := c.MkDir()
+	err := os.Mkdir(filepath.Join(dir, "layers"), 0755)
+	c.Assert(err, IsNil)
+	manager, err := servstate.NewManager(s.st, s.runner, dir, nil, nil, fakeLogManager{})
+	c.Assert(err, IsNil)
+	defer manager.Stop()
+
+	outputPath := filepath.Join(dir, "output")
+	layer := parseLayer(c, 0, "layer", fmt.Sprintf(`
+services:
+    wrkdir:
+        override: replace
+        command: /bin/sh -c "pwd >%s; sleep %g"
+        working-dir: %s
+`, outputPath, shortOkayDelay.Seconds()+0.01, dir))
+	err = manager.AppendLayer(layer)
+	c.Assert(err, IsNil)
+
+	chg := s.startServices(c, []string{"wrkdir"}, 1)
+	s.st.Lock()
+	c.Assert(chg.Err(), IsNil)
+	s.st.Unlock()
+
+	output, err := ioutil.ReadFile(outputPath)
+	c.Assert(err, IsNil)
+	c.Check(string(output), Equals, dir+"\n")
+}

internals/plan/plan.go

@@ -79,6 +79,7 @@ type Service struct {
 	User        string            `yaml:"user,omitempty"`
 	GroupID     *int              `yaml:"group-id,omitempty"`
 	Group       string            `yaml:"group,omitempty"`
+	WorkingDir  string            `yaml:"working-dir,omitempty"`
 
 	// Auto-restart and backoff functionality
 	OnSuccess      ServiceAction            `yaml:"on-success,omitempty"`
@@ -154,6 +155,9 @@ func (s *Service) Merge(other *Service) {
 	if other.Group != "" {
 		s.Group = other.Group
 	}
+	if other.WorkingDir != "" {
+		s.WorkingDir = other.WorkingDir
+	}
 	s.After = append(s.After, other.After...)
 	s.Before = append(s.Before, other.Before...)
 	s.Requires = append(s.Requires, other.Requires...)

internals/plan/plan_test.go

@@ -107,12 +107,14 @@ var planTests = []planTest{{
 				backoff-delay: 1s
 				backoff-factor: 1.5
 				backoff-limit: 10s
+				working-dir: /workdir/srv1
 			srv2:
 				override: replace
 				startup: enabled
 				command: cmd
 				before:
 					- srv3
+				working-dir: /workdir/srv2
 			srv3:
 				override: replace
 				command: cmd
@@ -131,6 +133,7 @@ var planTests = []planTest{{
 					- srv4
 				before:
 					- srv5
+				working-dir: /workdir/srv1/override
 			srv2:
 				override: replace
 				startup: disabled
@@ -173,16 +176,18 @@ var planTests = []planTest{{
 					"var0": "val0",
 					"var2": "val2",
 				},
+				WorkingDir:    "/workdir/srv1",
 				BackoffDelay:  plan.OptionalDuration{Value: time.Second, IsSet: true},
 				BackoffFactor: plan.OptionalFloat{Value: 1.5, IsSet: true},
 				BackoffLimit:  plan.OptionalDuration{Value: 10 * time.Second, IsSet: true},
 			},
 			"srv2": {
-				Name:     "srv2",
-				Override: "replace",
-				Command:  "cmd",
-				Startup:  plan.StartupEnabled,
-				Before:   []string{"srv3"},
+				Name:       "srv2",
+				Override:   "replace",
+				Command:    "cmd",
+				WorkingDir: "/workdir/srv2",
+				Startup:    plan.StartupEnabled,
+				Before:     []string{"srv3"},
 			},
 			"srv3": {
 				Name:     "srv3",
@@ -213,6 +218,7 @@ var planTests = []planTest{{
 				Environment: map[string]string{
 					"var3": "val3",
 				},
+				WorkingDir: "/workdir/srv1/override",
 			},
 			"srv2": {
 				Name:     "srv2",
@@ -269,6 +275,7 @@ var planTests = []planTest{{
 					"var2": "val2",
 					"var3": "val3",
 				},
+				WorkingDir:    "/workdir/srv1/override",
 				BackoffDelay:  plan.OptionalDuration{Value: time.Second, IsSet: true},
 				BackoffFactor: plan.OptionalFloat{Value: 1.5, IsSet: true},
 				BackoffLimit:  plan.OptionalDuration{Value: 10 * time.Second, IsSet: true},