journald event logging

contrib/cirrus/setup_environment.sh

@@ -55,6 +55,7 @@ then
     # Some setup needs to vary between distros
     case "${OS_RELEASE_ID}-${OS_RELEASE_VER}" in
         ubuntu-18)
+            sudo apt-get -qq -y install libsystemd-dev
             # Always install runc on Ubuntu
             install_runc_from_git
             ;;

docs/podman-events.1.md

@@ -9,7 +9,9 @@ podman\-events - Monitor Podman events
 ## DESCRIPTION
 
 Monitor and print events that occur in Podman. Each event will include a timestamp,
-a type, a status, name (if applicable), and image (if applicable).
+a type, a status, name (if applicable), and image (if applicable).  The default logging
+mechanism is *journald*. This can be changed in libpod.conf by changing the `events_logger`
+value to `file`.  Only `file` and `journald` are the accepted.
 
 The *container* event type will report the follow statuses:
  * attach

libpod.conf

@@ -113,3 +113,7 @@ runc = [
 	    "/bin/runc",
 	    "/usr/lib/cri-o-runc/sbin/runc"
 ]
+
+# Selects which logging mechanism to use for Podman events.  Valid values
+# are `journald` or `file`.
+events_logger = "journald"

libpod/events.go

@@ -1,23 +1,28 @@
 package libpod
 
 import (
-	"os"
-
 	"github.com/containers/libpod/libpod/events"
-	"github.com/hpcloud/tail"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
+// newEventer returns an eventer that can be used to read/write events
+func (r *Runtime) newEventer() (events.Eventer, error) {
+	options := events.EventerOptions{
+		EventerType: r.config.EventsLogger,
+		LogFilePath: r.config.EventsLogFilePath,
+	}
+	return events.NewEventer(options)
+}
+
 // newContainerEvent creates a new event based on a container
 func (c *Container) newContainerEvent(status events.Status) {
 	e := events.NewEvent(status)
 	e.ID = c.ID()
 	e.Name = c.Name()
 	e.Image = c.config.RootfsImageName
 	e.Type = events.Container
-	if err := e.Write(c.runtime.config.EventsLogFilePath); err != nil {
-		logrus.Errorf("unable to write event to %s", c.runtime.config.EventsLogFilePath)
+	if err := c.runtime.eventer.Write(e); err != nil {
+		logrus.Errorf("unable to write pod event: %q", err)
 	}
 }
 
@@ -29,8 +34,8 @@ func (c *Container) newContainerExitedEvent(exitCode int32) {
 	e.Image = c.config.RootfsImageName
 	e.Type = events.Container
 	e.ContainerExitCode = int(exitCode)
-	if err := e.Write(c.runtime.config.EventsLogFilePath); err != nil {
-		logrus.Errorf("unable to write event to %s", c.runtime.config.EventsLogFilePath)
+	if err := c.runtime.eventer.Write(e); err != nil {
+		logrus.Errorf("unable to write pod event: %q", err)
 	}
 }
 
@@ -40,8 +45,8 @@ func (p *Pod) newPodEvent(status events.Status) {
 	e.ID = p.ID()
 	e.Name = p.Name()
 	e.Type = events.Pod
-	if err := e.Write(p.runtime.config.EventsLogFilePath); err != nil {
-		logrus.Errorf("unable to write event to %s", p.runtime.config.EventsLogFilePath)
+	if err := p.runtime.eventer.Write(e); err != nil {
+		logrus.Errorf("unable to write pod event: %q", err)
 	}
 }
 
@@ -50,51 +55,17 @@ func (v *Volume) newVolumeEvent(status events.Status) {
 	e := events.NewEvent(status)
 	e.Name = v.Name()
 	e.Type = events.Volume
-	if err := e.Write(v.runtime.config.EventsLogFilePath); err != nil {
-		logrus.Errorf("unable to write event to %s", v.runtime.config.EventsLogFilePath)
+	if err := v.runtime.eventer.Write(e); err != nil {
+		logrus.Errorf("unable to write volume event: %q", err)
 	}
 }
 
 // Events is a wrapper function for everyone to begin tailing the events log
 // with options
-func (r *Runtime) Events(fromStart, stream bool, options []events.EventFilter, eventChannel chan *events.Event) error {
-	if !r.valid {
-		return ErrRuntimeStopped
-	}
-
-	t, err := r.getTail(fromStart, stream)
+func (r *Runtime) Events(options events.ReadOptions) error {
+	eventer, err := r.newEventer()
 	if err != nil {
 		return err
 	}
-	for line := range t.Lines {
-		event, err := events.NewEventFromString(line.Text)
-		if err != nil {
-			return err
-		}
-		switch event.Type {
-		case events.Image, events.Volume, events.Pod, events.Container:
-		//	no-op
-		default:
-			return errors.Errorf("event type %s is not valid in %s", event.Type.String(), r.config.EventsLogFilePath)
-		}
-		include := true
-		for _, filter := range options {
-			include = include && filter(event)
-		}
-		if include {
-			eventChannel <- event
-		}
-	}
-	close(eventChannel)
-	return nil
-}
-
-func (r *Runtime) getTail(fromStart, stream bool) (*tail.Tail, error) {
-	reopen := true
-	seek := tail.SeekInfo{Offset: 0, Whence: os.SEEK_END}
-	if fromStart || !stream {
-		seek.Whence = 0
-		reopen = false
-	}
-	return tail.TailFile(r.config.EventsLogFilePath, tail.Config{ReOpen: reopen, Follow: stream, Location: &seek, Logger: tail.DiscardingLogger})
+	return eventer.Read(options)
 }

libpod/events/config.go

@@ -0,0 +1,149 @@
+package events
+
+import (
+	"time"
+)
+
+// EventerType ...
+type EventerType int
+
+const (
+	// LogFile indicates the event logger will be a logfile
+	LogFile EventerType = iota
+	// Journald indicates journald should be used to log events
+	Journald EventerType = iota
+)
+
+// Event describes the attributes of a libpod event
+type Event struct {
+	// ContainerExitCode is for storing the exit code of a container which can
+	// be used for "internal" event notification
+	ContainerExitCode int
+	// ID can be for the container, image, volume, etc
+	ID string
+	// Image used where applicable
+	Image string
+	// Name where applicable
+	Name string
+	// Status describes the event that occurred
+	Status Status
+	// Time the event occurred
+	Time time.Time
+	// Type of event that occurred
+	Type Type
+}
+
+// EventerOptions describe options that need to be passed to create
+// an eventer
+type EventerOptions struct {
+	// EventerType describes whether to use journald or a file
+	EventerType string
+	// LogFilePath is the path to where the log file should reside if using
+	// the file logger
+	LogFilePath string
+}
+
+// Eventer is the interface for journald or file event logging
+type Eventer interface {
+	// Write an event to a backend
+	Write(event Event) error
+	// Read an event from the backend
+	Read(options ReadOptions) error
+}
+
+// ReadOptions describe the attributes needed to read event logs
+type ReadOptions struct {
+	// EventChannel is the comm path back to user
+	EventChannel chan *Event
+	// Filters are key/value pairs that describe to limit output
+	Filters []string
+	// FromStart means you start reading from the start of the logs
+	FromStart bool
+	// Since reads "since" the given time
+	Since string
+	// Stream is follow
+	Stream bool
+	// Until reads "until" the given time
+	Until string
+}
+
+// Type of event that occurred (container, volume, image, pod, etc)
+type Type string
+
+// Status describes the actual event action (stop, start, create, kill)
+type Status string
+
+const (
+	// If you add or subtract any values to the following lists, make sure you also update
+	// the switch statements below and the enums for EventType or EventStatus in the
+	// varlink description file.
+
+	// Container - event is related to containers
+	Container Type = "container"
+	// Image - event is related to images
+	Image Type = "image"
+	// Pod - event is related to pods
+	Pod Type = "pod"
+	// Volume - event is related to volumes
+	Volume Type = "volume"
+
+	// Attach ...
+	Attach Status = "attach"
+	// Checkpoint ...
+	Checkpoint Status = "checkpoint"
+	// Cleanup ...
+	Cleanup Status = "cleanup"
+	// Commit ...
+	Commit Status = "commit"
+	// Create ...
+	Create Status = "create"
+	// Exec ...
+	Exec Status = "exec"
+	// Exited indicates that a container's process died
+	Exited Status = "died"
+	// Export ...
+	Export Status = "export"
+	// History ...
+	History Status = "history"
+	// Import ...
+	Import Status = "import"
+	// Init ...
+	Init Status = "init"
+	// Kill ...
+	Kill Status = "kill"
+	// LoadFromArchive ...
+	LoadFromArchive Status = "loadfromarchive"
+	// Mount ...
+	Mount Status = "mount"
+	// Pause ...
+	Pause Status = "pause"
+	// Prune ...
+	Prune Status = "prune"
+	// Pull ...
+	Pull Status = "pull"
+	// Push ...
+	Push Status = "push"
+	// Remove ...
+	Remove Status = "remove"
+	// Restore ...
+	Restore Status = "restore"
+	// Save ...
+	Save Status = "save"
+	// Start ...
+	Start Status = "start"
+	// Stop ...
+	Stop Status = "stop"
+	// Sync ...
+	Sync Status = "sync"
+	// Tag ...
+	Tag Status = "tag"
+	// Unmount ...
+	Unmount Status = "unmount"
+	// Unpause ...
+	Unpause Status = "unpause"
+	// Untag ...
+	Untag Status = "untag"
+)
+
+// EventFilter for filtering events
+type EventFilter func(*Event) bool