Merge pull request #424 from fnproject/call-listener

CallListener - replaces RunnerListener

api/agent/agent.go

@@ -15,6 +15,7 @@ import (
 	"github.com/fnproject/fn/api/agent/drivers/docker"
 	"github.com/fnproject/fn/api/agent/protocol"
 	"github.com/fnproject/fn/api/common"
+	"github.com/fnproject/fn/api/extensions"
 	"github.com/fnproject/fn/api/id"
 	"github.com/fnproject/fn/api/models"
 	"github.com/opentracing/opentracing-go"
@@ -110,12 +111,14 @@ type Agent interface {
 
 	// Return the http.Handler used to handle Prometheus metric requests
 	PromHandler() http.Handler
+	AddCallListener(extensions.CallListener)
 }
 
 type agent struct {
 	// TODO maybe these should be on GetCall? idk. was getting bloated.
-	mq models.MessageQueue
-	ds models.Datastore
+	mq            models.MessageQueue
+	ds            models.Datastore
+	callListeners []extensions.CallListener
 
 	driver drivers.Driver
 
@@ -207,7 +210,7 @@ func (a *agent) Submit(callI Call) error {
 	defer slot.Close() // notify our slot is free once we're done
 
 	// TODO Start is checking the timer now, we could do it here, too.
-	err = call.Start(ctx)
+	err = call.Start(ctx, a)
 	if err != nil {
 		a.stats.Dequeue(callI.Model().Path)
 		return err
@@ -231,8 +234,7 @@ func (a *agent) Submit(callI Call) error {
 	// TODO: we need to allocate more time to store the call + logs in case the call timed out,
 	// but this could put us over the timeout if the call did not reply yet (need better policy).
 	ctx = opentracing.ContextWithSpan(context.Background(), span)
-	call.End(ctx, err)
-
+	err = call.End(ctx, err, a)
 	return err
 }
 

api/agent/call.go

@@ -29,13 +29,13 @@ type Call interface {
 	// etc.
 	// TODO Start and End can likely be unexported as they are only used in the agent,
 	// and on a type which is constructed in a specific agent. meh.
-	Start(ctx context.Context) error
+	Start(ctx context.Context, t callTrigger) error
 
 	// End will be called immediately after attempting a call execution,
 	// regardless of whether the execution failed or not. An error will be passed
 	// to End, which if nil indicates a successful execution. Any error returned
 	// from End will be returned as the error from Submit.
-	End(ctx context.Context, err error)
+	End(ctx context.Context, err error, t callTrigger) error
 }
 
 // TODO build w/o closures... lazy
@@ -278,7 +278,7 @@ type call struct {
 
 func (c *call) Model() *models.Call { return c.Call }
 
-func (c *call) Start(ctx context.Context) error {
+func (c *call) Start(ctx context.Context, t callTrigger) error {
 	span, ctx := opentracing.StartSpanFromContext(ctx, "agent_call_start")
 	defer span.Finish()
 
@@ -316,22 +316,28 @@ func (c *call) Start(ctx context.Context) error {
 			return err // let another thread try this
 		}
 	}
+
+	err := t.fireBeforeCall(ctx, c.Model())
+	if err != nil {
+		return fmt.Errorf("BeforeCall: %v", err)
+	}
+
 	return nil
 }
 
-func (c *call) End(ctx context.Context, err error) {
+func (c *call) End(ctx context.Context, errIn error, t callTrigger) error {
 	span, ctx := opentracing.StartSpanFromContext(ctx, "agent_call_end")
 	defer span.Finish()
 
 	c.CompletedAt = strfmt.DateTime(time.Now())
 
-	switch err {
+	switch errIn {
 	case nil:
 		c.Status = "success"
 	case context.DeadlineExceeded:
 		c.Status = "timeout"
 	default:
-		// XXX (reed): should we append the error to logs? Error field?
+		// XXX (reed): should we append the error to logs? Error field? (TR) yes, think so, otherwise it's lost looks like?
 		c.Status = "error"
 	}
 
@@ -344,14 +350,21 @@ func (c *call) End(ctx context.Context, err error) {
 	// TODO: this should be update, really
 	if err := c.ds.InsertCall(ctx, c.Call); err != nil {
 		common.Logger(ctx).WithError(err).Error("error inserting call into datastore")
+		// note: Not returning err here since the job could have already finished successfully.
 	}
 
 	if err := c.ds.InsertLog(ctx, c.AppName, c.ID, c.stderr); err != nil {
 		common.Logger(ctx).WithError(err).Error("error uploading log")
+		// note: Not returning err here since the job could have already finished successfully.
 	}
 
 	// NOTE call this after InsertLog or the buffer will get reset
 	c.stderr.Close()
+	err := t.fireAfterCall(ctx, c.Model())
+	if err != nil {
+		return fmt.Errorf("AfterCall: %v", err)
+	}
+	return errIn
 }
 
 func fakeHandler(http.ResponseWriter, *http.Request, Params) {}

api/agent/listeners.go

@@ -0,0 +1,37 @@
+package agent
+
+import (
+	"context"
+
+	"github.com/fnproject/fn/api/extensions"
+	"github.com/fnproject/fn/api/models"
+)
+
+type callTrigger interface {
+	fireBeforeCall(context.Context, *models.Call) error
+	fireAfterCall(context.Context, *models.Call) error
+}
+
+func (a *agent) AddCallListener(listener extensions.CallListener) {
+	a.callListeners = append(a.callListeners, listener)
+}
+
+func (a *agent) fireBeforeCall(ctx context.Context, call *models.Call) error {
+	for _, l := range a.callListeners {
+		err := l.BeforeCall(ctx, call)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (a *agent) fireAfterCall(ctx context.Context, call *models.Call) error {
+	for _, l := range a.callListeners {
+		err := l.AfterCall(ctx, call)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}