get last container event

an internal change in libpod will soon required the ability to lookup
the last container event using the continer name or id and the type of
event.  this pr is in preperation for that need.

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

4 files changed, 71 insertions, 1 deletions

diff --git a/libpod/events.go b/libpod/events.go
index 13bb5bdde..be21e510a 100644
--- a/libpod/events.go
+++ b/libpod/events.go
@@ -1,7 +1,10 @@
 package libpod
 
 import (
+	"fmt"
+
 	"github.com/containers/libpod/libpod/events"
+	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -79,3 +82,55 @@ func (r *Runtime) Events(options events.ReadOptions) error {
 	}
 	return eventer.Read(options)
 }
+
+// GetEvents reads the event log and returns events based on input filters
+func (r *Runtime) GetEvents(filters []string) ([]*events.Event, error) {
+	var (
+		logEvents []*events.Event
+		readErr   error
+	)
+	eventChannel := make(chan *events.Event)
+	options := events.ReadOptions{
+		EventChannel: eventChannel,
+		Filters:      filters,
+		FromStart:    true,
+		Stream:       false,
+	}
+	eventer, err := r.newEventer()
+	if err != nil {
+		return nil, err
+	}
+	go func() {
+		readErr = eventer.Read(options)
+	}()
+	if readErr != nil {
+		return nil, readErr
+	}
+	for e := range eventChannel {
+		logEvents = append(logEvents, e)
+	}
+	return logEvents, nil
+}
+
+// GetLastContainerEvent takes a container name or ID and an event status and returns
+// the last occurrence of the container event
+func (r *Runtime) GetLastContainerEvent(nameOrID string, containerEvent events.Status) (*events.Event, error) {
+	// check to make sure the event.Status is valid
+	if _, err := events.StringToStatus(containerEvent.String()); err != nil {
+		return nil, err
+	}
+	filters := []string{
+		fmt.Sprintf("container=%s", nameOrID),
+		fmt.Sprintf("event=%s", containerEvent),
+		"type=container",
+	}
+	containerEvents, err := r.GetEvents(filters)
+	if err != nil {
+		return nil, err
+	}
+	if len(containerEvents) < 1 {
+		return nil, errors.Wrapf(events.ErrEventNotFound, "%s not found", containerEvent.String())
+	}
+	// return the last element in the slice
+	return containerEvents[len(containerEvents)-1], nil
+}
diff --git a/libpod/events/config.go b/libpod/events/config.go
index 810988205..b9f01f3a5 100644
--- a/libpod/events/config.go
+++ b/libpod/events/config.go
@@ -2,6 +2,8 @@ package events
 
 import (
 	"time"
+
+	"github.com/pkg/errors"
 )
 
 // EventerType ...
@@ -158,3 +160,12 @@ const (
 
 // EventFilter for filtering events
 type EventFilter func(*Event) bool
+
+var (
+	// ErrEventTypeBlank indicates the event log found something done by podman
+	// but it isnt likely an event
+	ErrEventTypeBlank = errors.New("event type blank")
+
+	// ErrEventNotFound indicates that the event was not found in the event log
+	ErrEventNotFound = errors.New("unable to find event")
+)
diff --git a/libpod/events/events.go b/libpod/events/events.go
index 1ec79bcd7..2bebff162 100644
--- a/libpod/events/events.go
+++ b/libpod/events/events.go
@@ -95,6 +95,8 @@ func StringToType(name string) (Type, error) {
 		return System, nil
 	case Volume.String():
 		return Volume, nil
+	case "":
+		return "", ErrEventTypeBlank
 	}
 	return "", errors.Errorf("unknown event type %q", name)
 }
diff --git a/libpod/events/journal_linux.go b/libpod/events/journal_linux.go
index 78a630e9a..d5bce4334 100644
--- a/libpod/events/journal_linux.go
+++ b/libpod/events/journal_linux.go
@@ -101,7 +101,9 @@ func (e EventJournalD) Read(options ReadOptions) error {
 			// We can't decode this event.
 			// Don't fail hard - that would make events unusable.
 			// Instead, log and continue.
-			logrus.Errorf("Unable to decode event: %v", err)
+			if errors.Cause(err) != ErrEventTypeBlank {
+				logrus.Errorf("Unable to decode event: %v", err)
+			}
 			continue
 		}
 		include := true