Merge pull request #1374 from alienth/systemd

Add collector for systemd service status.

_third_party/github.com/coreos/go-systemd/dbus/dbus.go

@@ -0,0 +1,187 @@
+// Copyright 2015 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.
+
+// Integration with the systemd D-Bus API.  See http://www.freedesktop.org/wiki/Software/systemd/dbus/
+package dbus
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+
+	"bosun.org/_third_party/github.com/godbus/dbus"
+)
+
+const (
+	alpha        = `abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ`
+	num          = `0123456789`
+	alphanum     = alpha + num
+	signalBuffer = 100
+)
+
+// needsEscape checks whether a byte in a potential dbus ObjectPath needs to be escaped
+func needsEscape(i int, b byte) bool {
+	// Escape everything that is not a-z-A-Z-0-9
+	// Also escape 0-9 if it's the first character
+	return strings.IndexByte(alphanum, b) == -1 ||
+		(i == 0 && strings.IndexByte(num, b) != -1)
+}
+
+// PathBusEscape sanitizes a constituent string of a dbus ObjectPath using the
+// rules that systemd uses for serializing special characters.
+func PathBusEscape(path string) string {
+	// Special case the empty string
+	if len(path) == 0 {
+		return "_"
+	}
+	n := []byte{}
+	for i := 0; i < len(path); i++ {
+		c := path[i]
+		if needsEscape(i, c) {
+			e := fmt.Sprintf("_%x", c)
+			n = append(n, []byte(e)...)
+		} else {
+			n = append(n, c)
+		}
+	}
+	return string(n)
+}
+
+// Conn is a connection to systemd's dbus endpoint.
+type Conn struct {
+	// sysconn/sysobj are only used to call dbus methods
+	sysconn *dbus.Conn
+	sysobj  dbus.BusObject
+
+	// sigconn/sigobj are only used to receive dbus signals
+	sigconn *dbus.Conn
+	sigobj  dbus.BusObject
+
+	jobListener struct {
+		jobs map[dbus.ObjectPath]chan<- string
+		sync.Mutex
+	}
+	subscriber struct {
+		updateCh chan<- *SubStateUpdate
+		errCh    chan<- error
+		sync.Mutex
+		ignore      map[dbus.ObjectPath]int64
+		cleanIgnore int64
+	}
+}
+
+// New establishes a connection to the system bus and authenticates.
+// Callers should call Close() when done with the connection.
+func New() (*Conn, error) {
+	return newConnection(func() (*dbus.Conn, error) {
+		return dbusAuthHelloConnection(dbus.SystemBusPrivate)
+	})
+}
+
+// NewUserConnection establishes a connection to the session bus and
+// authenticates. This can be used to connect to systemd user instances.
+// Callers should call Close() when done with the connection.
+func NewUserConnection() (*Conn, error) {
+	return newConnection(func() (*dbus.Conn, error) {
+		return dbusAuthHelloConnection(dbus.SessionBusPrivate)
+	})
+}
+
+// NewSystemdConnection establishes a private, direct connection to systemd.
+// This can be used for communicating with systemd without a dbus daemon.
+// Callers should call Close() when done with the connection.
+func NewSystemdConnection() (*Conn, error) {
+	return newConnection(func() (*dbus.Conn, error) {
+		// We skip Hello when talking directly to systemd.
+		return dbusAuthConnection(func() (*dbus.Conn, error) {
+			return dbus.Dial("unix:path=/run/systemd/private")
+		})
+	})
+}
+
+// Close closes an established connection
+func (c *Conn) Close() {
+	c.sysconn.Close()
+	c.sigconn.Close()
+}
+
+func newConnection(createBus func() (*dbus.Conn, error)) (*Conn, error) {
+	sysconn, err := createBus()
+	if err != nil {
+		return nil, err
+	}
+
+	sigconn, err := createBus()
+	if err != nil {
+		sysconn.Close()
+		return nil, err
+	}
+
+	c := &Conn{
+		sysconn: sysconn,
+		sysobj:  systemdObject(sysconn),
+		sigconn: sigconn,
+		sigobj:  systemdObject(sigconn),
+	}
+
+	c.subscriber.ignore = make(map[dbus.ObjectPath]int64)
+	c.jobListener.jobs = make(map[dbus.ObjectPath]chan<- string)
+
+	// Setup the listeners on jobs so that we can get completions
+	c.sigconn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
+		"type='signal', interface='org.freedesktop.systemd1.Manager', member='JobRemoved'")
+
+	c.dispatch()
+	return c, nil
+}
+
+func dbusAuthConnection(createBus func() (*dbus.Conn, error)) (*dbus.Conn, error) {
+	conn, err := createBus()
+	if err != nil {
+		return nil, err
+	}
+
+	// Only use EXTERNAL method, and hardcode the uid (not username)
+	// to avoid a username lookup (which requires a dynamically linked
+	// libc)
+	methods := []dbus.Auth{dbus.AuthExternal(strconv.Itoa(os.Getuid()))}
+
+	err = conn.Auth(methods)
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	return conn, nil
+}
+
+func dbusAuthHelloConnection(createBus func() (*dbus.Conn, error)) (*dbus.Conn, error) {
+	conn, err := dbusAuthConnection(createBus)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = conn.Hello(); err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	return conn, nil
+}
+
+func systemdObject(conn *dbus.Conn) dbus.BusObject {
+	return conn.Object("org.freedesktop.systemd1", dbus.ObjectPath("/org/freedesktop/systemd1"))
+}

_third_party/github.com/coreos/go-systemd/dbus/dbus_test.go

@@ -0,0 +1,77 @@
+// Copyright 2015 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 dbus
+
+import (
+	"testing"
+)
+
+func TestNeedsEscape(t *testing.T) {
+	// Anything not 0-9a-zA-Z should always be escaped
+	for want, vals := range map[bool][]byte{
+		false: []byte{'a', 'b', 'z', 'A', 'Q', '1', '4', '9'},
+		true:  []byte{'#', '%', '$', '!', '.', '_', '-', '%', '\\'},
+	} {
+		for i := 1; i < 10; i++ {
+			for _, b := range vals {
+				got := needsEscape(i, b)
+				if got != want {
+					t.Errorf("needsEscape(%d, %c) returned %t, want %t", i, b, got, want)
+				}
+			}
+		}
+	}
+
+	// 0-9 in position 0 should be escaped
+	for want, vals := range map[bool][]byte{
+		false: []byte{'A', 'a', 'e', 'x', 'Q', 'Z'},
+		true:  []byte{'0', '4', '5', '9'},
+	} {
+		for _, b := range vals {
+			got := needsEscape(0, b)
+			if got != want {
+				t.Errorf("needsEscape(0, %c) returned %t, want %t", b, got, want)
+			}
+		}
+	}
+
+}
+
+func TestPathBusEscape(t *testing.T) {
+	for in, want := range map[string]string{
+		"":                   "_",
+		"foo.service":        "foo_2eservice",
+		"foobar":             "foobar",
+		"woof@woof.service":  "woof_40woof_2eservice",
+		"0123456":            "_30123456",
+		"account_db.service": "account_5fdb_2eservice",
+		"got-dashes":         "got_2ddashes",
+	} {
+		got := PathBusEscape(in)
+		if got != want {
+			t.Errorf("bad result for PathBusEscape(%s): got %q, want %q", in, got, want)
+		}
+	}
+
+}
+
+// TestNew ensures that New() works without errors.
+func TestNew(t *testing.T) {
+	_, err := New()
+
+	if err != nil {
+		t.Fatal(err)
+	}
+}