func (c *ec2MetadataClientImpl) ReadResource(path string) ([]byte, error) {
endpoint := c.ResourceServiceUrl(path)
var err error
var resp *http.Response
utils.RetryNWithBackoff(utils.NewSimpleBackoff(metadataRetryStartDelay, metadataRetryMaxDelay, metadataRetryDelayMultiple, 0.2), metadataRetries, func() error {
resp, err = c.client.Get(endpoint)
if err == nil && resp.StatusCode == 200 {
return nil
}
if resp != nil && resp.Body != nil {
resp.Body.Close()
}
if err == nil {
seelog.Warnf("Error accessing the EC2 Metadata Service; non-200 response: %v", resp.StatusCode)
return fmt.Errorf("Error contacting EC2 Metadata service; non-200 response: %v", resp.StatusCode)
} else {
seelog.Warnf("Error accessing the EC2 Metadata Service; retrying: %v", err)
return err
}
})
if resp != nil && resp.Body != nil {
defer resp.Body.Close()
}
if err != nil {
return nil, err
}
return ioutil.ReadAll(resp.Body)
}
// ServeHttp serves IAM Role Credentials for Tasks being managed by the agent.
func ServeHttp(credentialsManager credentials.Manager, containerInstanceArn string, cfg *config.Config) {
// Create and initialize the audit log
// TODO Use seelog's programmatic configuration instead of xml.
logger, err := log.LoggerFromConfigAsString(audit.AuditLoggerConfig(cfg))
if err != nil {
log.Errorf("Error initializing the audit log: %v", err)
// If the logger cannot be initialized, use the provided dummy seelog.LoggerInterface, seelog.Disabled.
logger = log.Disabled
}
auditLogger := audit.NewAuditLog(containerInstanceArn, cfg, logger)
server := setupServer(credentialsManager, auditLogger)
for {
utils.RetryWithBackoff(utils.NewSimpleBackoff(time.Second, time.Minute, 0.2, 2), func() error {
// TODO, make this cancellable and use the passed in context;
err := server.ListenAndServe()
if err != nil {
log.Errorf("Error running http api: %v", err)
}
return err
})
}
}
// TestHandlerReconnectsCorrectlySetsSendCredentialsURLParameter tests if
// the 'sendCredentials' URL parameter is set correctly for successive
// invocations of startACSSession
func TestHandlerReconnectsCorrectlySetsSendCredentialsURLParameter(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
taskEngine := engine.NewMockTaskEngine(ctrl)
ecsClient := mock_api.NewMockECSClient(ctrl)
statemanager := statemanager.NewNoopStateManager()
ctx, cancel := context.WithCancel(context.Background())
mockWsClient := mock_wsclient.NewMockClientServer(ctrl)
args := StartSessionArguments{
ContainerInstanceArn: "myArn",
CredentialProvider: credentials.AnonymousCredentials,
Config: &config.Config{Cluster: "someCluster"},
TaskEngine: taskEngine,
ECSClient: ecsClient,
StateManager: statemanager,
AcceptInvalidCert: true,
_heartbeatTimeout: 20 * time.Millisecond,
_heartbeatJitter: 10 * time.Millisecond,
}
session := newSessionResources(args)
mockWsClient.EXPECT().SetAnyRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().AddRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().Close().Return(nil).AnyTimes()
mockWsClient.EXPECT().Serve().Return(io.EOF).AnyTimes()
gomock.InOrder(
// When the websocket client connects to ACS for the first
// time, 'sendCredentials' should be set to true
mockWsClient.EXPECT().Connect().Do(func() {
validateSendCredentialsInSession(t, session, "true")
}).Return(nil),
// For all subsequent connections to ACS, 'sendCredentials'
// should be set to false
mockWsClient.EXPECT().Connect().Do(func() {
validateSendCredentialsInSession(t, session, "false")
}).Return(nil).AnyTimes(),
)
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
timer := newDisconnectionTimer(mockWsClient, args.time(), args.heartbeatTimeout(), args.heartbeatJitter())
defer timer.Stop()
go func() {
for i := 0; i < 10; i++ {
startACSSession(ctx, mockWsClient, timer, args, backoff, session)
}
cancel()
}()
// Wait for context to be cancelled
select {
case <-ctx.Done():
}
}
// StartSession creates a session with the backend and handles requests
// using the passed in arguments.
// The engine is expected to initialized and gathering container metrics by
// the time the websocket client starts using it.
func StartSession(params TelemetrySessionParams, statsEngine stats.Engine) error {
backoff := utils.NewSimpleBackoff(time.Second, 1*time.Minute, 0.2, 2)
for {
tcsError := startTelemetrySession(params, statsEngine)
if tcsError == nil || tcsError == io.EOF {
backoff.Reset()
} else {
log.Info("Error from tcs; backing off", "err", tcsError)
ttime.Sleep(backoff.Duration())
}
}
}
// TestHandlerReconnectsOnServeErrors tests if the handler retries to
// to establish the session with ACS when ClientServer.Connect() returns errors
func TestHandlerReconnectsOnServeErrors(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
taskEngine := engine.NewMockTaskEngine(ctrl)
taskEngine.EXPECT().Version().Return("Docker: 1.5.0", nil).AnyTimes()
ecsClient := mock_api.NewMockECSClient(ctrl)
ecsClient.EXPECT().DiscoverPollEndpoint(gomock.Any()).Return(acsURL, nil).AnyTimes()
statemanager := statemanager.NewNoopStateManager()
ctx, cancel := context.WithCancel(context.Background())
mockWsClient := mock_wsclient.NewMockClientServer(ctrl)
mockWsClient.EXPECT().SetAnyRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().AddRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().Connect().Return(nil).AnyTimes()
mockWsClient.EXPECT().Close().Return(nil).AnyTimes()
gomock.InOrder(
// Serve fails 10 times
mockWsClient.EXPECT().Serve().Return(io.EOF).Times(10),
// Cancel trying to Serve ACS requests on the 11th attempt
// Failure to retry on Serve() errors should cause the
// test to time out as the context is never cancelled
mockWsClient.EXPECT().Serve().Do(func() {
cancel()
}).Return(io.EOF),
)
session := &mockSession{mockWsClient}
args := StartSessionArguments{
ContainerInstanceArn: "myArn",
CredentialProvider: credentials.AnonymousCredentials,
Config: &config.Config{Cluster: "someCluster"},
TaskEngine: taskEngine,
ECSClient: ecsClient,
StateManager: statemanager,
AcceptInvalidCert: true,
_heartbeatTimeout: 20 * time.Millisecond,
_heartbeatJitter: 10 * time.Millisecond,
}
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
go func() {
startSession(ctx, args, backoff, session)
}()
// Wait for context to be cancelled
select {
case <-ctx.Done():
}
}
func ServeHttp(containerInstanceArn *string, taskEngine engine.TaskEngine, cfg *config.Config) {
serverFunctions := map[string]func(w http.ResponseWriter, r *http.Request){
"/v1/metadata": MetadataV1RequestHandlerMaker(containerInstanceArn, cfg),
"/v1/tasks": TasksV1RequestHandlerMaker(taskEngine),
"/license": LicenseHandler,
}
paths := make([]string, 0, len(serverFunctions))
for path := range serverFunctions {
paths = append(paths, path)
}
availableCommands := &RootResponse{paths}
// Autogenerated list of the above serverFunctions paths
availableCommandResponse, _ := json.Marshal(&availableCommands)
defaultHandler := func(w http.ResponseWriter, r *http.Request) {
w.Write(availableCommandResponse)
}
serverMux := http.NewServeMux()
serverMux.HandleFunc("/", defaultHandler)
for key, fn := range serverFunctions {
serverMux.HandleFunc(key, fn)
}
// Log all requests and then pass through to serverMux
loggingServeMux := http.NewServeMux()
loggingServeMux.Handle("/", LoggingHandler{serverMux})
server := http.Server{
Addr: ":" + strconv.Itoa(config.AGENT_INTROSPECTION_PORT),
Handler: loggingServeMux,
ReadTimeout: 5 * time.Second,
WriteTimeout: 5 * time.Second,
}
for {
once := sync.Once{}
utils.RetryWithBackoff(utils.NewSimpleBackoff(time.Second, time.Minute, 0.2, 2), func() error {
// TODO, make this cancellable and use the passed in context; for
// now, not critical if this gets interrupted
err := server.ListenAndServe()
once.Do(func() {
log.Error("Error running http api", "err", err)
})
return err
})
}
}
// TestConnectionIsClosedOnIdle tests if the connection to ACS is closed
// when the channel is idle
func TestConnectionIsClosedOnIdle(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
taskEngine := engine.NewMockTaskEngine(ctrl)
taskEngine.EXPECT().Version().Return("Docker: 1.5.0", nil).AnyTimes()
ecsClient := mock_api.NewMockECSClient(ctrl)
statemanager := statemanager.NewNoopStateManager()
mockWsClient := mock_wsclient.NewMockClientServer(ctrl)
mockWsClient.EXPECT().SetAnyRequestHandler(gomock.Any()).Do(func(v interface{}) {}).AnyTimes()
mockWsClient.EXPECT().AddRequestHandler(gomock.Any()).Do(func(v interface{}) {}).AnyTimes()
mockWsClient.EXPECT().Connect().Return(nil)
mockWsClient.EXPECT().Serve().Do(func() {
// Pretend as if the maximum heartbeatTimeout duration has
// been breached while Serving requests
time.Sleep(30 * time.Millisecond)
}).Return(io.EOF)
connectionClosed := make(chan bool)
mockWsClient.EXPECT().Close().Do(func() {
// Record connection closed
connectionClosed <- true
}).Return(nil)
ctx := context.Background()
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
args := StartSessionArguments{
ContainerInstanceArn: "myArn",
CredentialProvider: credentials.AnonymousCredentials,
Config: &config.Config{Cluster: "someCluster"},
TaskEngine: taskEngine,
ECSClient: ecsClient,
StateManager: statemanager,
AcceptInvalidCert: true,
_heartbeatTimeout: 20 * time.Millisecond,
_heartbeatJitter: 10 * time.Millisecond,
}
go func() {
timer := newDisconnectionTimer(mockWsClient, args.time(), args.heartbeatTimeout(), args.heartbeatJitter())
defer timer.Stop()
startACSSession(ctx, mockWsClient, timer, args, backoff, &mockSession{})
}()
// Wait for connection to be closed. If the connection is not closed
// due to inactivity, the test will time out
<-connectionClosed
}
// MustInit blocks and retries until an engine can be initialized.
func (engine *DockerTaskEngine) MustInit() {
if engine.client != nil {
return
}
errorOnce := sync.Once{}
taskEngineConnectBackoff := utils.NewSimpleBackoff(200*time.Millisecond, 2*time.Second, 0.20, 1.5)
utils.RetryWithBackoff(taskEngineConnectBackoff, func() error {
err := engine.Init()
if err != nil {
errorOnce.Do(func() {
log.Error("Could not connect to docker daemon", "err", err)
})
}
return err
})
}
// ServeHttp serves information about this agent / containerInstance and tasks
// running on it.
func ServeHttp(containerInstanceArn *string, taskEngine engine.TaskEngine, cfg *config.Config) {
// Is this the right level to type assert, assuming we'd abstract multiple taskengines here?
// Revisit if we ever add another type..
dockerTaskEngine := taskEngine.(*engine.DockerTaskEngine)
server := setupServer(containerInstanceArn, dockerTaskEngine, cfg)
for {
once := sync.Once{}
utils.RetryWithBackoff(utils.NewSimpleBackoff(time.Second, time.Minute, 0.2, 2), func() error {
// TODO, make this cancellable and use the passed in context; for
// now, not critical if this gets interrupted
err := server.ListenAndServe()
once.Do(func() {
log.Error("Error running http api", "err", err)
})
return err
})
}
}
// StartSession creates a session with the backend and handles requests
// using the passed in arguments.
// The engine is expected to initialized and gathering container metrics by
// the time the websocket client starts using it.
func StartSession(params TelemetrySessionParams, statsEngine stats.Engine) error {
backoff := utils.NewSimpleBackoff(time.Second, 1*time.Minute, 0.2, 2)
for {
tcsEndpoint, err := params.EcsClient.DiscoverTelemetryEndpoint(params.ContainerInstanceArn)
if err != nil {
log.Error("Unable to discover poll endpoint", "err", err)
return err
}
log.Debug("Connecting to TCS endpoint " + tcsEndpoint)
url := formatURL(tcsEndpoint, params.Cfg.Cluster, params.ContainerInstanceArn)
tcsError := startSession(url, params.Cfg.AWSRegion, params.CredentialProvider, params.AcceptInvalidCert, statsEngine, defaultPublishMetricsInterval)
if tcsError == nil || tcsError == io.EOF {
backoff.Reset()
} else {
log.Info("Error from tcs; backing off", "err", tcsError)
ttime.Sleep(backoff.Duration())
}
}
}
// StartSession creates a session with ACS and handles requests from ACS.
// It creates resources required to invoke the package scoped 'startSession()'
// method and invokes the same to repeatedly connect to ACS when disconnected
func StartSession(ctx context.Context, args StartSessionArguments) error {
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
session := newSessionResources(args)
return startSession(ctx, args, backoff, session)
}
// Continuously retries sending an event until it succeeds, sleeping between each
// attempt
func SubmitTaskEvents(events *eventList, client api.ECSClient) {
backoff := utils.NewSimpleBackoff(1*time.Second, 30*time.Second, 0.20, 1.3)
// Mirror events.sending, but without the need to lock since this is local
// to our goroutine
done := false
for !done {
// If we looped back up here, we successfully submitted an event, but
// we haven't emptied the list so we should keep submitting
backoff.Reset()
utils.RetryWithBackoff(backoff, func() error {
// Lock and unlock within this function, allowing the list to be added
// to while we're not actively sending an event
log.Debug("Waiting on semaphore to send...")
handler.submitSemaphore.Wait()
defer handler.submitSemaphore.Post()
log.Debug("Aquiring lock for sending event...")
events.Lock()
defer events.Unlock()
log.Debug("Aquired lock!")
var err utils.RetriableError
if events.Len() == 0 {
log.Debug("No events left; not retrying more")
events.sending = false
done = true
return nil
}
eventToSubmit := events.Front()
event := eventToSubmit.Value.(*sendableEvent)
llog := log.New("event", event)
if event.containerShouldBeSent() {
llog.Info("Sending container change", "change", event.containerChange)
err = client.SubmitContainerStateChange(event.containerChange)
if err == nil || !err.Retry() {
// submitted or can't be retried; ensure we don't retry it
event.containerSent = true
if event.containerChange.SentStatus != nil {
*event.containerChange.SentStatus = event.containerChange.Status
}
statesaver.Save()
if err != nil {
llog.Error("Unretriable error submitting container state change", "err", err)
} else {
llog.Debug("Submitted container")
}
events.Remove(eventToSubmit)
} // else, leave event on and retry it next loop through
} else if event.taskShouldBeSent() {
llog.Info("Sending task change", "change", event.taskChange)
err = client.SubmitTaskStateChange(event.taskChange)
if err == nil || !err.Retry() {
// submitted or can't be retried; ensure we don't retry it
event.taskSent = true
if event.taskChange.SentStatus != nil {
*event.taskChange.SentStatus = event.taskChange.Status
}
statesaver.Save()
if err != nil {
llog.Error("Unretriable error submitting container state change", "err", err)
} else {
llog.Debug("Submitted container")
backoff.Reset()
}
events.Remove(eventToSubmit)
}
} else {
// Shouldn't be sent as either a task or container change event; must have been already sent
llog.Info("Not submitting redundant event; just removing")
events.Remove(eventToSubmit)
}
if events.Len() == 0 {
llog.Debug("Removed the last element, no longer sending")
events.sending = false
done = true
return nil
}
return err
})
}
}
// StartSession creates a session with ACS and handles requests using the passed
// in arguments.
func StartSession(ctx context.Context, args StartSessionArguments) error {
ecsclient := args.ECSClient
cfg := args.Config
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
payloadBuffer := make(chan *ecsacs.PayloadMessage, payloadMessageBufferSize)
ackBuffer := make(chan string, payloadMessageBufferSize)
go func() {
// Handle any payloads async. For correctness, they must be handled in order, hence the buffered channel which is added to synchronously.
for {
select {
case payload := <-payloadBuffer:
handlePayloadMessage(ackBuffer, cfg.Cluster, args.ContainerInstanceArn, payload, args.TaskEngine, ecsclient, args.StateManager)
case <-ctx.Done():
return
}
}
}()
for {
acsError := func() error {
acsEndpoint, err := ecsclient.DiscoverPollEndpoint(args.ContainerInstanceArn)
if err != nil {
log.Error("Unable to discover poll endpoint", "err", err)
return err
}
log.Debug("Connecting to ACS endpoint " + acsEndpoint)
url := AcsWsUrl(acsEndpoint, cfg.Cluster, args.ContainerInstanceArn, args.TaskEngine)
clearStrChannel(ackBuffer)
client := acsclient.New(url, cfg.AWSRegion, args.CredentialProvider, args.AcceptInvalidCert)
defer client.Close()
// Clear the ackbuffer whenever we get a new client because acks of
// messageids don't have any value across sessions
defer clearStrChannel(ackBuffer)
timer := ttime.AfterFunc(utils.AddJitter(heartbeatTimeout, heartbeatJitter), func() {
log.Warn("ACS Connection hasn't had any activity for too long; closing connection")
closeErr := client.Close()
if closeErr != nil {
log.Warn("Error disconnecting: " + closeErr.Error())
}
})
defer timer.Stop()
// Any message from the server resets the disconnect timeout
client.SetAnyRequestHandler(anyMessageHandler(timer))
client.AddRequestHandler(payloadMessageHandler(payloadBuffer))
// Ignore heartbeat messages; anyMessageHandler gets 'em
client.AddRequestHandler(func(*ecsacs.HeartbeatMessage) {})
updater.AddAgentUpdateHandlers(client, cfg, args.StateManager, args.TaskEngine)
err = client.Connect()
if err != nil {
log.Error("Error connecting to ACS: " + err.Error())
return err
}
ttime.AfterFunc(utils.AddJitter(heartbeatTimeout, heartbeatJitter), func() {
// If we do not have an error connecting and remain connected for at
// least 5 or so minutes, reset the backoff. This prevents disconnect
// errors that only happen infrequently from damaging the
// reconnectability as significantly.
backoff.Reset()
})
serveErr := make(chan error, 1)
go func() {
serveErr <- client.Serve()
}()
for {
select {
case mid := <-ackBuffer:
ackMessageId(client, cfg.Cluster, args.ContainerInstanceArn, mid)
case <-ctx.Done():
return ctx.Err()
case err := <-serveErr:
return err
}
}
}()
select {
case <-ctx.Done():
return ctx.Err()
default:
}
if acsError == nil || acsError == io.EOF {
backoff.Reset()
} else {
log.Info("Error from acs; backing off", "err", acsError)
ttime.Sleep(backoff.Duration())
}
}
}
// TestHandlerReconnectsOnDiscoverPollEndpointError tests if handler retries
// to establish the session with ACS on DiscoverPollEndpoint errors
func TestHandlerReconnectsOnDiscoverPollEndpointError(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
taskEngine := engine.NewMockTaskEngine(ctrl)
taskEngine.EXPECT().Version().Return("Docker: 1.5.0", nil).AnyTimes()
ecsClient := mock_api.NewMockECSClient(ctrl)
statemanager := statemanager.NewNoopStateManager()
ctx, cancel := context.WithCancel(context.Background())
mockWsClient := mock_wsclient.NewMockClientServer(ctrl)
mockWsClient.EXPECT().SetAnyRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().AddRequestHandler(gomock.Any()).AnyTimes()
mockWsClient.EXPECT().Connect().Return(nil).AnyTimes()
mockWsClient.EXPECT().Close().Return(nil).AnyTimes()
mockWsClient.EXPECT().Serve().Do(func() {
// Serve() cancels the context
cancel()
}).Return(io.EOF)
session := &mockSession{mockWsClient}
gomock.InOrder(
// DiscoverPollEndpoint returns an error on its first invocation
ecsClient.EXPECT().DiscoverPollEndpoint(gomock.Any()).Return("", fmt.Errorf("oops")).Times(1),
// Second invocation returns a success
ecsClient.EXPECT().DiscoverPollEndpoint(gomock.Any()).Return(acsURL, nil).Times(1),
)
args := StartSessionArguments{
ContainerInstanceArn: "myArn",
CredentialProvider: credentials.AnonymousCredentials,
Config: &config.Config{Cluster: "someCluster"},
TaskEngine: taskEngine,
ECSClient: ecsClient,
StateManager: statemanager,
AcceptInvalidCert: true,
_heartbeatTimeout: 20 * time.Millisecond,
_heartbeatJitter: 10 * time.Millisecond,
}
backoff := utils.NewSimpleBackoff(connectionBackoffMin, connectionBackoffMax, connectionBackoffJitter, connectionBackoffMultiplier)
go func() {
startSession(ctx, args, backoff, session)
}()
start := time.Now()
// Wait for context to be cancelled
select {
case <-ctx.Done():
}
// Measure the duration between retries
timeSinceStart := time.Since(start)
if timeSinceStart < connectionBackoffMin {
t.Errorf("Duration since start is less than minimum threshold for backoff: %s", timeSinceStart.String())
}
// The upper limit here should really be connectionBackoffMin + (connectionBackoffMin * jitter)
// But, it can be off by a few milliseconds to account for execution of other instructions
// In any case, it should never be higher than 2*connectionBackoffMin
if timeSinceStart > 2*connectionBackoffMin {
t.Errorf("Duration since start is greater than maximum anticipated wait time: %v", timeSinceStart.String())
}
}
