Merge pull request #6838 from mheon/fix_panic_events

Fix `system service` panic from early hangup in events

libpod/events.go

@@ -1,6 +1,7 @@
 package libpod
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/containers/libpod/libpod/events"
@@ -75,16 +76,16 @@ func (v *Volume) newVolumeEvent(status events.Status) {
 
 // Events is a wrapper function for everyone to begin tailing the events log
 // with options
-func (r *Runtime) Events(options events.ReadOptions) error {
+func (r *Runtime) Events(ctx context.Context, options events.ReadOptions) error {
 	eventer, err := r.newEventer()
 	if err != nil {
 		return err
 	}
-	return eventer.Read(options)
+	return eventer.Read(ctx, options)
 }
 
 // GetEvents reads the event log and returns events based on input filters
-func (r *Runtime) GetEvents(filters []string) ([]*events.Event, error) {
+func (r *Runtime) GetEvents(ctx context.Context, filters []string) ([]*events.Event, error) {
 	var readErr error
 	eventChannel := make(chan *events.Event)
 	options := events.ReadOptions{
@@ -98,7 +99,7 @@ func (r *Runtime) GetEvents(filters []string) ([]*events.Event, error) {
 		return nil, err
 	}
 	go func() {
-		readErr = eventer.Read(options)
+		readErr = eventer.Read(ctx, options)
 	}()
 	if readErr != nil {
 		return nil, readErr
@@ -112,7 +113,7 @@ func (r *Runtime) GetEvents(filters []string) ([]*events.Event, error) {
 
 // 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) {
+func (r *Runtime) GetLastContainerEvent(ctx context.Context, 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
@@ -122,7 +123,7 @@ func (r *Runtime) GetLastContainerEvent(nameOrID string, containerEvent events.S
 		fmt.Sprintf("event=%s", containerEvent),
 		"type=container",
 	}
-	containerEvents, err := r.GetEvents(filters)
+	containerEvents, err := r.GetEvents(ctx, filters)
 	if err != nil {
 		return nil, err
 	}

libpod/events/config.go

@@ -1,6 +1,7 @@
 package events
 
 import (
+	"context"
 	"time"
 
 	"github.com/pkg/errors"
@@ -52,7 +53,7 @@ type Eventer interface {
 	// Write an event to a backend
 	Write(event Event) error
 	// Read an event from the backend
-	Read(options ReadOptions) error
+	Read(ctx context.Context, options ReadOptions) error
 	// String returns the type of event logger
 	String() string
 }

libpod/events/journal_linux.go

@@ -3,6 +3,7 @@
 package events
 
 import (
+	"context"
 	"fmt"
 	"strconv"
 	"time"
@@ -53,7 +54,7 @@ func (e EventJournalD) Write(ee Event) error {
 }
 
 // Read reads events from the journal and sends qualified events to the event channel
-func (e EventJournalD) Read(options ReadOptions) error {
+func (e EventJournalD) Read(ctx context.Context, options ReadOptions) error {
 	defer close(options.EventChannel)
 	eventOptions, err := generateEventOptions(options.Filters, options.Since, options.Until)
 	if err != nil {

libpod/events/logfile.go

@@ -1,6 +1,7 @@
 package events
 
 import (
+	"context"
 	"fmt"
 	"os"
 
@@ -40,7 +41,7 @@ func (e EventLogFile) Write(ee Event) error {
 }
 
 // Reads from the log file
-func (e EventLogFile) Read(options ReadOptions) error {
+func (e EventLogFile) Read(ctx context.Context, options ReadOptions) error {
 	defer close(options.EventChannel)
 	eventOptions, err := generateEventOptions(options.Filters, options.Since, options.Until)
 	if err != nil {
@@ -50,6 +51,17 @@ func (e EventLogFile) Read(options ReadOptions) error {
 	if err != nil {
 		return err
 	}
+	funcDone := make(chan bool)
+	copy := true
+	go func() {
+		select {
+		case <-funcDone:
+			// Do nothing
+		case <-ctx.Done():
+			copy = false
+			t.Kill(errors.New("hangup by client"))
+		}
+	}()
 	for line := range t.Lines {
 		event, err := newEventFromJSONString(line.Text)
 		if err != nil {
@@ -65,10 +77,11 @@ func (e EventLogFile) Read(options ReadOptions) error {
 		for _, filter := range eventOptions {
 			include = include && filter(event)
 		}
-		if include {
+		if include && copy {
 			options.EventChannel <- event
 		}
 	}
+	funcDone <- true
 	return nil
 }
 

libpod/events/nullout.go

@@ -1,5 +1,9 @@
 package events
 
+import (
+	"context"
+)
+
 // EventToNull is an eventer type that only performs write operations
 // and only writes to /dev/null. It is meant for unittests only
 type EventToNull struct{}
@@ -10,7 +14,7 @@ func (e EventToNull) Write(ee Event) error {
 }
 
 // Read does nothing. Do not use it.
-func (e EventToNull) Read(options ReadOptions) error {
+func (e EventToNull) Read(ctx context.Context, options ReadOptions) error {
 	return nil
 }
 

pkg/api/handlers/compat/events.go

@@ -1,6 +1,7 @@
 package compat
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 
@@ -45,13 +46,15 @@ func GetEvents(w http.ResponseWriter, r *http.Request) {
 		fromStart = true
 	}
 
+	eventCtx, eventCancel := context.WithCancel(r.Context())
 	eventChannel := make(chan *events.Event)
 	go func() {
 		readOpts := events.ReadOptions{FromStart: fromStart, Stream: query.Stream, Filters: libpodFilters, EventChannel: eventChannel, Since: query.Since, Until: query.Until}
-		eventsError = runtime.Events(readOpts)
+		eventsError = runtime.Events(eventCtx, readOpts)
 	}()
 	if eventsError != nil {
 		utils.InternalServerError(w, eventsError)
+		eventCancel()
 		close(eventChannel)
 		return
 	}
@@ -59,6 +62,7 @@ func GetEvents(w http.ResponseWriter, r *http.Request) {
 	// If client disappears we need to stop listening for events
 	go func(done <-chan struct{}) {
 		<-done
+		eventCancel()
 		if _, ok := <-eventChannel; ok {
 			close(eventChannel)
 		}

pkg/domain/infra/abi/containers.go

@@ -741,7 +741,7 @@ func (ic *ContainerEngine) ContainerStart(ctx context.Context, namesOrIds []stri
 			if ecode, err := ctr.Wait(); err != nil {
 				if errors.Cause(err) == define.ErrNoSuchCtr {
 					// Check events
-					event, err := ic.Libpod.GetLastContainerEvent(ctr.ID(), events.Exited)
+					event, err := ic.Libpod.GetLastContainerEvent(ctx, ctr.ID(), events.Exited)
 					if err != nil {
 						logrus.Errorf("Cannot get exit code: %v", err)
 						exitCode = define.ExecErrorCodeNotFound
@@ -871,7 +871,7 @@ func (ic *ContainerEngine) ContainerRun(ctx context.Context, opts entities.Conta
 	if ecode, err := ctr.Wait(); err != nil {
 		if errors.Cause(err) == define.ErrNoSuchCtr {
 			// Check events
-			event, err := ic.Libpod.GetLastContainerEvent(ctr.ID(), events.Exited)
+			event, err := ic.Libpod.GetLastContainerEvent(ctx, ctr.ID(), events.Exited)
 			if err != nil {
 				logrus.Errorf("Cannot get exit code: %v", err)
 				report.ExitCode = define.ExecErrorCodeNotFound

pkg/domain/infra/abi/events.go

@@ -9,5 +9,5 @@ import (
 
 func (ic *ContainerEngine) Events(ctx context.Context, opts entities.EventsOptions) error {
 	readOpts := events.ReadOptions{FromStart: opts.FromStart, Stream: opts.Stream, Filters: opts.Filter, EventChannel: opts.EventChan, Since: opts.Since, Until: opts.Until}
-	return ic.Libpod.Events(readOpts)
+	return ic.Libpod.Events(ctx, readOpts)
 }

pkg/varlinkapi/attach.go

@@ -4,6 +4,7 @@ package varlinkapi
 
 import (
 	"bufio"
+	"context"
 	"io"
 
 	"github.com/containers/libpod/libpod"
@@ -89,7 +90,7 @@ func (i *VarlinkAPI) Attach(call iopodman.VarlinkCall, name string, detachKeys s
 		if ecode, err := ctr.Wait(); err != nil {
 			if errors.Cause(err) == define.ErrNoSuchCtr {
 				// Check events
-				event, err := i.Runtime.GetLastContainerEvent(ctr.ID(), events.Exited)
+				event, err := i.Runtime.GetLastContainerEvent(context.Background(), ctr.ID(), events.Exited)
 				if err != nil {
 					logrus.Errorf("Cannot get exit code: %v", err)
 					exitCode = define.ExecErrorCodeNotFound

pkg/varlinkapi/events.go

@@ -3,6 +3,7 @@
 package varlinkapi
 
 import (
+	"context"
 	"time"
 
 	"github.com/containers/libpod/libpod/events"
@@ -27,7 +28,7 @@ func (i *VarlinkAPI) GetEvents(call iopodman.VarlinkCall, filter []string, since
 	eventChannel := make(chan *events.Event)
 	go func() {
 		readOpts := events.ReadOptions{FromStart: fromStart, Stream: stream, Filters: filter, EventChannel: eventChannel}
-		eventsError = i.Runtime.Events(readOpts)
+		eventsError = i.Runtime.Events(context.Background(), readOpts)
 	}()
 	if eventsError != nil {
 		return call.ReplyErrorOccurred(eventsError.Error())