Preload systemdUnitManager hash cache

pkg/filesystem.go

@@ -0,0 +1,44 @@
+/*
+   Copyright 2014 CoreOS, Inc.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package pkg
+
+import (
+	"io/ioutil"
+)
+
+// ListDirectory generates a slice of all the file names that both exist in
+// the provided directory and pass the filter.
+// The returned file names are relative to the directory argument.
+// filterFunc is called once for each file found in the directory. If
+// filterFunc returns true, the given file will ignored.
+func ListDirectory(dir string, filterFunc func(string) bool) ([]string, error) {
+	fis, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	units := make([]string, 0)
+	for _, fi := range fis {
+		name := fi.Name()
+		if filterFunc(name) {
+			continue
+		}
+		units = append(units, name)
+	}
+
+	return units, nil
+}

pkg/filesystem_test.go

@@ -0,0 +1,55 @@
+/*
+   Copyright 2014 CoreOS, Inc.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package pkg
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+	"testing"
+)
+
+func TestListDirectory(t *testing.T) {
+	dir, err := ioutil.TempDir("", "fleet-testing-")
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	defer os.RemoveAll(dir)
+
+	for _, name := range []string{"ping", "pong", "foo", "bar", "baz"} {
+		err := ioutil.WriteFile(path.Join(dir, name), []byte{}, 0400)
+		if err != nil {
+			t.Fatal(err.Error())
+		}
+	}
+
+	filterFunc := func(name string) bool {
+		return name == "foo" || name == "bar"
+	}
+
+	got, err := ListDirectory(dir, filterFunc)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	want := []string{"baz", "ping", "pong"}
+	if !reflect.DeepEqual(want, got) {
+		t.Fatalf("ListDirectory output incorrect: want=%v, got=%v", want, got)
+	}
+}

systemd/manager.go

@@ -36,7 +36,7 @@ const (
 
 type systemdUnitManager struct {
 	systemd  *dbus.Conn
-	UnitsDir string
+	unitsDir string
 
 	hashes map[string]unit.Hash
 	mutex  sync.RWMutex
@@ -52,15 +52,53 @@ func NewSystemdUnitManager(uDir string) (*systemdUnitManager, error) {
 		return nil, err
 	}
 
+	hashes, err := hashUnitFiles(uDir)
+	if err != nil {
+		return nil, err
+	}
+
 	mgr := systemdUnitManager{
 		systemd:  systemd,
-		UnitsDir: uDir,
-		hashes:   make(map[string]unit.Hash),
+		unitsDir: uDir,
+		hashes:   hashes,
 		mutex:    sync.RWMutex{},
 	}
 	return &mgr, nil
 }
 
+func hashUnitFiles(dir string) (map[string]unit.Hash, error) {
+	uNames, err := lsUnitsDir(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	hMap := make(map[string]unit.Hash)
+	for _, uName := range uNames {
+		h, err := hashUnitFile(path.Join(dir, uName))
+		if err != nil {
+			return nil, err
+		}
+
+		hMap[uName] = h
+	}
+
+	return hMap, nil
+}
+
+func hashUnitFile(loc string) (unit.Hash, error) {
+	b, err := ioutil.ReadFile(loc)
+	if err != nil {
+		return unit.Hash{}, err
+	}
+
+	uf, err := unit.NewUnitFile(string(b))
+	if err != nil {
+		return unit.Hash{}, err
+	}
+
+	return uf.Hash(), nil
+}
+
 // Load writes the given Unit to disk, subscribing to relevant dbus
 // events, caching the Unit's Hash, and, if necessary, instructing the systemd
 // daemon to reload.
@@ -163,21 +201,9 @@ func (m *systemdUnitManager) daemonReload() error {
 
 // Units enumerates all files recognized as valid systemd units in
 // this manager's units directory.
-func (m *systemdUnitManager) Units() (units []string, err error) {
-	fis, err := ioutil.ReadDir(m.UnitsDir)
-	if err != nil {
-		return
-	}
+func (m *systemdUnitManager) Units() ([]string, error) {
+	return lsUnitsDir(m.unitsDir)
 
-	for _, fi := range fis {
-		name := fi.Name()
-		if !unit.RecognizedUnitType(name) {
-			log.Warningf("Found unrecognized file in %s, ignoring", path.Join(m.UnitsDir, name))
-			continue
-		}
-		units = append(units, name)
-	}
-	return
 }
 
 func (m *systemdUnitManager) GetUnitStates(filter pkg.Set) (map[string]*unit.UnitState, error) {
@@ -256,5 +282,18 @@ func (m *systemdUnitManager) removeUnit(name string) {
 }
 
 func (m *systemdUnitManager) getUnitFilePath(name string) string {
-	return path.Join(m.UnitsDir, name)
+	return path.Join(m.unitsDir, name)
+}
+
+func lsUnitsDir(dir string) ([]string, error) {
+	filterFunc := func(name string) bool {
+		if !unit.RecognizedUnitType(name) {
+			log.Warningf("Found unrecognized file in %s, ignoring", path.Join(dir, name))
+			return true
+		}
+
+		return false
+	}
+
+	return pkg.ListDirectory(dir, filterFunc)
 }

systemd/manager_test.go

@@ -0,0 +1,115 @@
+/*
+   Copyright 2014 CoreOS, Inc.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package systemd
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+	"testing"
+)
+
+func TestHashUnitFile(t *testing.T) {
+	f, err := ioutil.TempFile("", "fleet-testing-")
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	defer os.Remove(f.Name())
+
+	contents := `
+[Service]
+ExecStart=/usr/bin/sleep infinity
+`
+
+	if _, err := f.Write([]byte(contents)); err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	if err := f.Close(); err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	hash, err := hashUnitFile(f.Name())
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	want := "40ea6646945809f4b420a50475ee68503088f127"
+	got := hash.String()
+	if want != got {
+		t.Fatalf("unit hash incorrect: want=%s, got=%s", want, got)
+	}
+}
+
+func TestHashUnitFileDirectory(t *testing.T) {
+	dir, err := ioutil.TempDir("", "fleet-testing-")
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	defer os.RemoveAll(dir)
+
+	fixtures := []struct {
+		name     string
+		contents string
+		hash     string
+	}{
+		{
+			name:     "foo.service",
+			contents: "[Service]\nExecStart=/usr/bin/sleep infinity",
+			hash:     "40ea6646945809f4b420a50475ee68503088f127",
+		},
+		{
+			name:     "bar.service",
+			contents: "[Service]\nExecStart=/usr/bin/sleep 10",
+			hash:     "5bf16b98c62f35fcdc723d32989cdeba7a2dd2a8",
+		},
+		{
+			name:     "baz.service",
+			contents: "[Service]\nExecStart=/usr/bin/sleep 2000",
+			hash:     "5ba5292ab6a82b623ee6086dc90b3354ba004832",
+		},
+	}
+
+	for _, f := range fixtures {
+		err := ioutil.WriteFile(path.Join(dir, f.name), []byte(f.contents), 0400)
+		if err != nil {
+			t.Fatal(err.Error())
+		}
+	}
+
+	hashes, err := hashUnitFileDirectory(dir)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	got := make(map[string]string, len(hashes))
+	for uName, hash := range hashes {
+		got[uName] = hash.String()
+	}
+
+	want := make(map[string]string, len(fixtures))
+	for _, f := range fixtures {
+		want[f.name] = f.hash
+	}
+
+	if !reflect.DeepEqual(want, got) {
+		t.Fatalf("hashUnitFileDirectory returned unexpected values: want=%v, got=%v", want, got)
+	}
+}