journald event logging

add the ability for podman to read and write events to journald instead
of just a logfile.  This can be controlled in libpod.conf with the
`events_logger` attribute of `journald` or `file`.  The default will be
set to `journald`.

Signed-off-by: baude <bbaude@redhat.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/libpod/events/logfile.go b/libpod/events/logfile.go
new file mode 100644
index 000000000..3232b86d0
--- /dev/null
+++ b/libpod/events/logfile.go
@@ -0,0 +1,65 @@
+package events
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/pkg/errors"
+)
+
+// EventLogFile is the structure for event writing to a logfile. It contains the eventer
+// options and the event itself.  Methods for reading and writing are also defined from it.
+type EventLogFile struct {
+	options EventerOptions
+}
+
+// Writes to the log file
+func (e EventLogFile) Write(ee Event) error {
+	f, err := os.OpenFile(e.options.LogFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0700)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	eventJSONString, err := ee.ToJSONString()
+	if err != nil {
+		return err
+	}
+	if _, err := f.WriteString(fmt.Sprintf("%s\n", eventJSONString)); err != nil {
+		return err
+	}
+	return nil
+
+}
+
+// Reads from the log file
+func (e EventLogFile) Read(options ReadOptions) error {
+	eventOptions, err := generateEventOptions(options.Filters, options.Since, options.Until)
+	if err != nil {
+		return errors.Wrapf(err, "unable to generate event options")
+	}
+	t, err := e.getTail(options)
+	if err != nil {
+		return err
+	}
+	for line := range t.Lines {
+		event, err := newEventFromJSONString(line.Text)
+		if err != nil {
+			return err
+		}
+		switch event.Type {
+		case Image, Volume, Pod, Container:
+		//	no-op
+		default:
+			return errors.Errorf("event type %s is not valid in %s", event.Type.String(), e.options.LogFilePath)
+		}
+		include := true
+		for _, filter := range eventOptions {
+			include = include && filter(event)
+		}
+		if include {
+			options.EventChannel <- event
+		}
+	}
+	close(options.EventChannel)
+	return nil
+}