fn: I/O related improvements (#809)

*) I/O protocol parse issues should shutdown the container as the container
goes to inconsistent state between calls. (eg. next call may receive previous
calls left overs.)
*) Move ghost read/write code into io_utils in common.
*) Clean unused error from docker Wait()
*) We can catch one case in JSON, if there's remaining unparsed data in
decoder buffer, we can shut the container
*) stdout/stderr when container is not handling a request are now blocked if freezer is also enabled.
*) if a fatal err is set for slot, we do not requeue it and proceed to shutdown
*) added a test function for a few cases with freezer strict behavior

api/agent/agent.go

@@ -443,13 +443,13 @@ func (a *agent) launchCold(ctx context.Context, call *call) (Slot, error) {
 
 // implements Slot
 type coldSlot struct {
-	cookie drivers.Cookie
-	tok    ResourceToken
-	err    error
+	cookie   drivers.Cookie
+	tok      ResourceToken
+	fatalErr error
 }
 
 func (s *coldSlot) Error() error {
-	return s.err
+	return s.fatalErr
 }
 
 func (s *coldSlot) exec(ctx context.Context, call *call) error {
@@ -464,10 +464,8 @@ func (s *coldSlot) exec(ctx context.Context, call *call) error {
 		return err
 	}
 
-	res, err := waiter.Wait(ctx)
-	if err != nil {
-		return err
-	} else if res.Error() != nil {
+	res := waiter.Wait(ctx)
+	if res.Error() != nil {
 		// check for call error (oom/exit) and beam it up
 		return res.Error()
 	}
@@ -496,7 +494,7 @@ type hotSlot struct {
 	errC        <-chan error  // container error
 	container   *container    // TODO mask this
 	maxRespSize uint64        // TODO boo.
-	err         error
+	fatalErr    error
 }
 
 func (s *hotSlot) Close(ctx context.Context) error {
@@ -505,7 +503,7 @@ func (s *hotSlot) Close(ctx context.Context) error {
 }
 
 func (s *hotSlot) Error() error {
-	return s.err
+	return s.fatalErr
 }
 
 func (s *hotSlot) exec(ctx context.Context, call *call) error {
@@ -542,6 +540,15 @@ func (s *hotSlot) exec(ctx context.Context, call *call) error {
 	case err := <-s.errC: // error from container
 		return err
 	case err := <-errApp: // from dispatch
+		if s.fatalErr == nil && err != nil {
+			if models.IsAPIError(err) {
+				s.fatalErr = err
+			} else if err == protocol.ErrExcessData {
+				s.fatalErr = err
+				// suppress excess data error, but do shutdown the container
+				return nil
+			}
+		}
 		return err
 	case <-ctx.Done(): // call timeout
 		return ctx.Err()
@@ -604,42 +611,25 @@ func (a *agent) runHot(ctx context.Context, call *call, tok ResourceToken, state
 	state.UpdateState(ctx, ContainerStateStart, call.slots)
 	defer state.UpdateState(ctx, ContainerStateDone, call.slots)
 
-	cid := id.New().String()
-
-	// set up the stderr to capture any logs before the slot is executed and
-	// between hot functions
-	stderr := newLineWriter(&logWriter{
-		logrus.WithFields(logrus.Fields{"between_log": true, "app_name": call.AppName, "path": call.Path, "image": call.Image, "container_id": cid}),
-	})
-
-	// between calls we need a reader that doesn't do anything
-	stdin := &ghostReader{cond: sync.NewCond(new(sync.Mutex)), inner: new(waitReader)}
-	defer stdin.Close()
-
-	container := &container{
-		id:     cid, // XXX we could just let docker generate ids...
-		image:  call.Image,
-		env:    map[string]string(call.Config),
-		memory: call.Memory,
-		cpus:   uint64(call.CPUs),
-		stdin:  stdin,
-		stdout: &ghostWriter{inner: stderr},
-		stderr: &ghostWriter{inner: stderr},
-	}
+	// if freezer is enabled, be consistent with freezer behavior and
+	// block stdout and stderr between calls.
+	isBlockIdleIO := MaxDisabledMsecs != a.cfg.FreezeIdleMsecs
+	container, closer := NewHotContainer(call, isBlockIdleIO)
+	defer closer()
 
 	logger := logrus.WithFields(logrus.Fields{"id": container.id, "app": call.AppName, "route": call.Path, "image": call.Image, "memory": call.Memory, "cpus": call.CPUs, "format": call.Format, "idle_timeout": call.IdleTimeout})
 	ctx = common.WithLogger(ctx, logger)
 
 	cookie, err := a.driver.Prepare(ctx, container)
 	if err != nil {
-		call.slots.queueSlot(&hotSlot{done: make(chan struct{}), err: err})
+		call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: err})
 		return
 	}
 	defer cookie.Close(ctx) // NOTE ensure this ctx doesn't time out
 
 	waiter, err := cookie.Run(ctx)
 	if err != nil {
-		call.slots.queueSlot(&hotSlot{done: make(chan struct{}), err: err})
+		call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: err})
 		return
 	}
 
@@ -670,18 +660,20 @@ func (a *agent) runHot(ctx context.Context, call *call, tok ResourceToken, state
 			// wait for this call to finish
 			// NOTE do NOT select with shutdown / other channels. slot handles this.
 			<-slot.done
+
+			if slot.fatalErr != nil {
+				logger.WithError(slot.fatalErr).Info("hot function terminating")
+				return
+			}
 		}
 	}()
 
-	res, err := waiter.Wait(ctx)
-	if err != nil {
-		errC <- err
-	} else if res.Error() != nil {
-		err = res.Error()
-		errC <- err
+	res := waiter.Wait(ctx)
+	if res.Error() != nil {
+		errC <- res.Error() // TODO: race condition, no guaranteed delivery fix this...
 	}
 
-	logger.WithError(err).Info("hot function terminated")
+	logger.WithError(res.Error()).Info("hot function terminated")
 }
 
 // runHotReq enqueues a free slot to slot queue manager and watches various timers and the consumer until
@@ -790,11 +782,45 @@ type container struct {
 	stats   *drivers.Stats
 }
 
+func NewHotContainer(call *call, isBlockIdleIO bool) (*container, func()) {
+
+	id := id.New().String()
+
+	stdin := common.NewGhostReader()
+	stderr := common.NewGhostWriter()
+	stdout := common.NewGhostWriter()
+
+	// when not processing a request, do we block IO?
+	if !isBlockIdleIO {
+		stderr.Swap(newLineWriter(&logWriter{
+			logrus.WithFields(logrus.Fields{"tag": "stderr", "app_name": call.AppName, "path": call.Path, "image": call.Image, "container_id": id}),
+		}))
+		stdout.Swap(newLineWriter(&logWriter{
+			logrus.WithFields(logrus.Fields{"tag": "stdout", "app_name": call.AppName, "path": call.Path, "image": call.Image, "container_id": id}),
+		}))
+	}
+
+	return &container{
+			id:     id, // XXX we could just let docker generate ids...
+			image:  call.Image,
+			env:    map[string]string(call.Config),
+			memory: call.Memory,
+			cpus:   uint64(call.CPUs),
+			stdin:  stdin,
+			stdout: stdout,
+			stderr: stderr,
+		}, func() {
+			stdin.Close()
+			stderr.Close()
+			stdout.Close()
+		}
+}
+
 func (c *container) swap(stdin io.Reader, stdout, stderr io.Writer, cs *drivers.Stats) func() {
 	// if tests don't catch this, then fuck me
-	ostdin := c.stdin.(*ghostReader).swap(stdin)
-	ostdout := c.stdout.(*ghostWriter).swap(stdout)
-	ostderr := c.stderr.(*ghostWriter).swap(stderr)
+	ostdin := c.stdin.(common.GhostReader).Swap(stdin)
+	ostdout := c.stdout.(common.GhostWriter).Swap(stdout)
+	ostderr := c.stderr.(common.GhostWriter).Swap(stderr)
 
 	c.statsMu.Lock()
 	ocs := c.stats
@@ -802,9 +828,9 @@ func (c *container) swap(stdin io.Reader, stdout, stderr io.Writer, cs *drivers.
 	c.statsMu.Unlock()
 
 	return func() {
-		c.stdin.(*ghostReader).swap(ostdin)
-		c.stdout.(*ghostWriter).swap(ostdout)
-		c.stderr.(*ghostWriter).swap(ostderr)
+		c.stdin.(common.GhostReader).Swap(ostdin)
+		c.stdout.(common.GhostWriter).Swap(ostdout)
+		c.stderr.(common.GhostWriter).Swap(ostderr)
 		c.statsMu.Lock()
 		c.stats = ocs
 		c.statsMu.Unlock()
@@ -880,101 +906,3 @@ func init() {
 // Implementing the docker.AuthConfiguration interface.
 // TODO per call could implement this stored somewhere (vs. configured on host)
 //}
-
-// ghostWriter is an io.Writer who will pass writes to an inner writer
-// that may be changed at will. it is thread safe to swap or write.
-type ghostWriter struct {
-	sync.Mutex
-	inner io.Writer
-}
-
-func (g *ghostWriter) swap(w io.Writer) (old io.Writer) {
-	g.Lock()
-	old = g.inner
-	g.inner = w
-	g.Unlock()
-	return old
-}
-
-func (g *ghostWriter) Write(b []byte) (int, error) {
-	// we don't need to serialize writes but swapping g.inner could be a race if unprotected
-	g.Lock()
-	w := g.inner
-	g.Unlock()
-	n, err := w.Write(b)
-	if err == io.ErrClosedPipe {
-		// NOTE: we need to mask this error so that docker does not get an error
-		// from writing the output stream and shut down the container.
-		err = nil
-	}
-	return n, err
-}
-
-// ghostReader is an io.ReadCloser who will pass reads to an inner reader
-// that may be changed at will. it is thread safe to swap or read.
-// Read will wait for a 'real' reader if inner is of type *waitReader.
-// Close must be called to prevent any pending readers from leaking.
-type ghostReader struct {
-	cond   *sync.Cond
-	inner  io.Reader
-	closed bool
-}
-
-func (g *ghostReader) swap(r io.Reader) (old io.Reader) {
-	g.cond.L.Lock()
-	old = g.inner
-	g.inner = r
-	g.cond.L.Unlock()
-	g.cond.Broadcast()
-	return old
-}
-
-func (g *ghostReader) Close() {
-	g.cond.L.Lock()
-	g.closed = true
-	g.cond.L.Unlock()
-	g.cond.Broadcast()
-}
-
-func (g *ghostReader) awaitRealReader() (io.Reader, bool) {
-	// wait for a real reader
-	g.cond.L.Lock()
-	for {
-		if g.closed { // check this first
-			g.cond.L.Unlock()
-			return nil, false
-		}
-		if _, ok := g.inner.(*waitReader); ok {
-			g.cond.Wait()
-		} else {
-			break
-		}
-	}
-
-	// we don't need to serialize reads but swapping g.inner could be a race if unprotected
-	r := g.inner
-	g.cond.L.Unlock()
-	return r, true
-}
-
-func (g *ghostReader) Read(b []byte) (int, error) {
-	r, ok := g.awaitRealReader()
-	if !ok {
-		return 0, io.EOF
-	}
-
-	n, err := r.Read(b)
-	if err == io.ErrClosedPipe {
-		// NOTE: we need to mask this error so that docker does not get an error
-		// from reading the input stream and shut down the container.
-		err = nil
-	}
-	return n, err
-}
-
-// waitReader returns io.EOF if anyone calls Read. don't call Read, this is a sentinel type
-type waitReader struct{}
-
-func (e *waitReader) Read([]byte) (int, error) {
-	panic("read on waitReader should not happen")
-}

api/agent/config.go

@@ -15,6 +15,8 @@ type AgentConfig struct {
 	MaxResponseSize  uint64        `json:"max_response_size"`
 }
 
+var MaxDisabledMsecs = time.Duration(math.MaxInt64)
+
 func NewAgentConfig() (*AgentConfig, error) {
 
 	var err error
@@ -60,8 +62,8 @@ func getEnvMsecs(name string, defaultVal time.Duration) (time.Duration, error) {
 			return defaultVal, err
 		}
 		// disable if negative or set to msecs specified.
-		if durInt < 0 || time.Duration(durInt) >= math.MaxInt64/time.Millisecond {
-			delay = math.MaxInt64
+		if durInt < 0 || time.Duration(durInt) >= MaxDisabledMsecs/time.Millisecond {
+			delay = MaxDisabledMsecs
 		} else {
 			delay = time.Duration(durInt) * time.Millisecond
 		}

api/agent/drivers/docker/docker.go

@@ -384,7 +384,7 @@ type waitResult struct {
 }
 
 // waitResult implements drivers.WaitResult
-func (w *waitResult) Wait(ctx context.Context) (drivers.RunResult, error) {
+func (w *waitResult) Wait(ctx context.Context) drivers.RunResult {
 	defer close(w.done)
 
 	// wait until container is stopped (or ctx is cancelled if sooner)
@@ -392,7 +392,7 @@ func (w *waitResult) Wait(ctx context.Context) (drivers.RunResult, error) {
 	return &runResult{
 		status: status,
 		err:    err,
-	}, nil
+	}
 }
 
 // Repeatedly collect stats from the specified docker container until the stopSignal is closed or the context is cancelled

api/agent/drivers/docker/docker_test.go

@@ -56,9 +56,9 @@ func TestRunnerDocker(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	result, err := waiter.Wait(ctx)
-	if err != nil {
-		t.Fatal(err)
+	result := waiter.Wait(ctx)
+	if result.Error() != nil {
+		t.Fatal(result.Error())
 	}
 
 	if result.Status() != "success" {
@@ -109,9 +109,9 @@ func TestRunnerDockerStdin(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	result, err := waiter.Wait(ctx)
-	if err != nil {
-		t.Fatal(err)
+	result := waiter.Wait(ctx)
+	if result.Error() != nil {
+		t.Fatal(result.Error())
 	}
 
 	if result.Status() != "success" {

api/agent/drivers/driver.go

@@ -47,7 +47,7 @@ type WaitResult interface {
 	// provided context is canceled and the container does not return first, the
 	// resulting status will be 'canceled'. If the provided context times out
 	// then the resulting status will be 'timeout'.
-	Wait(context.Context) (RunResult, error)
+	Wait(context.Context) RunResult
 }
 
 type Driver interface {

api/agent/drivers/mock/mocker.go

@@ -52,6 +52,6 @@ type runResult struct {
 	start  time.Time
 }
 
-func (r *runResult) Wait(context.Context) (drivers.RunResult, error) { return r, nil }
-func (r *runResult) Status() string                                  { return r.status }
-func (r *runResult) Error() error                                    { return r.err }
+func (r *runResult) Wait(context.Context) drivers.RunResult { return r }
+func (r *runResult) Status() string                         { return r.status }
+func (r *runResult) Error() error                           { return r.err }

api/agent/protocol/factory.go

@@ -13,6 +13,8 @@ import (
 
 var errInvalidProtocol = errors.New("Invalid Protocol")
 
+var ErrExcessData = errors.New("Excess data in stream")
+
 type errorProto struct {
 	error
 }

api/agent/protocol/json.go

@@ -100,7 +100,8 @@ func (h *JSONProtocol) Dispatch(ctx context.Context, ci CallInfo, w io.Writer) e
 
 	_, span = trace.StartSpan(ctx, "dispatch_json_read_response")
 	var jout jsonOut
-	err = json.NewDecoder(h.out).Decode(&jout)
+	decoder := json.NewDecoder(h.out)
+	err = decoder.Decode(&jout)
 	span.End()
 	if err != nil {
 		return models.NewAPIError(http.StatusBadGateway, fmt.Errorf("invalid json response from function err: %v", err))
@@ -112,7 +113,8 @@ func (h *JSONProtocol) Dispatch(ctx context.Context, ci CallInfo, w io.Writer) e
 	rw, ok := w.(http.ResponseWriter)
 	if !ok {
 		// logs can just copy the full thing in there, headers and all.
-		return json.NewEncoder(w).Encode(jout)
+		err := json.NewEncoder(w).Encode(jout)
+		return h.isExcessData(err, decoder)
 	}
 
 	// this has to be done for pulling out:
@@ -141,5 +143,16 @@ func (h *JSONProtocol) Dispatch(ctx context.Context, ci CallInfo, w io.Writer) e
 	}
 
 	_, err = io.WriteString(rw, jout.Body)
+	return h.isExcessData(err, decoder)
+}
+
+func (h *JSONProtocol) isExcessData(err error, decoder *json.Decoder) error {
+	if err == nil {
+		// Now check for excess output, if this is the case, we can be certain that the next request will fail.
+		tmp, ok := decoder.Buffered().(*bytes.Reader)
+		if ok && tmp.Len() > 0 {
+			return ErrExcessData
+		}
+	}
 	return err
 }

api/common/io_utils.go

@@ -2,6 +2,7 @@ package common
 
 import (
 	"io"
+	"sync"
 )
 
 type clampWriter struct {
@@ -32,3 +33,161 @@ func (g *clampWriter) Write(p []byte) (int, error) {
 	}
 	return n, err
 }
+
+type GhostWriter interface {
+	io.Writer
+	io.Closer
+	Swap(r io.Writer) io.Writer
+}
+
+// ghostWriter is an io.Writer who will pass writes to an inner writer
+// that may be changed at will. it is thread safe to swap or write.
+type ghostWriter struct {
+	cond   *sync.Cond
+	inner  io.Writer
+	closed bool
+}
+
+func NewGhostWriter() GhostWriter {
+	return &ghostWriter{cond: sync.NewCond(new(sync.Mutex)), inner: new(waitWriter)}
+}
+
+func (g *ghostWriter) Swap(w io.Writer) (old io.Writer) {
+	g.cond.L.Lock()
+	old = g.inner
+	g.inner = w
+	g.cond.L.Unlock()
+	g.cond.Broadcast()
+	return old
+}
+
+func (g *ghostWriter) Close() error {
+	g.cond.L.Lock()
+	g.closed = true
+	g.cond.L.Unlock()
+	g.cond.Broadcast()
+	return nil
+}
+
+func (g *ghostWriter) awaitRealWriter() (io.Writer, bool) {
+	// wait for a real writer
+	g.cond.L.Lock()
+	for {
+		if g.closed { // check this first
+			g.cond.L.Unlock()
+			return nil, false
+		}
+		if _, ok := g.inner.(*waitWriter); ok {
+			g.cond.Wait()
+		} else {
+			break
+		}
+	}
+
+	// we don't need to serialize writes but swapping g.inner could be a race if unprotected
+	w := g.inner
+	g.cond.L.Unlock()
+	return w, true
+}
+
+func (g *ghostWriter) Write(b []byte) (int, error) {
+	w, ok := g.awaitRealWriter()
+	if !ok {
+		return 0, io.EOF
+	}
+
+	n, err := w.Write(b)
+	if err == io.ErrClosedPipe {
+		// NOTE: we need to mask this error so that docker does not get an error
+		// from writing the input stream and shut down the container.
+		err = nil
+	}
+	return n, err
+}
+
+type GhostReader interface {
+	io.Reader
+	io.Closer
+	Swap(r io.Reader) io.Reader
+}
+
+// ghostReader is an io.ReadCloser who will pass reads to an inner reader
+// that may be changed at will. it is thread safe to swap or read.
+// Read will wait for a 'real' reader if inner is of type *waitReader.
+// Close must be called to prevent any pending readers from leaking.
+type ghostReader struct {
+	cond   *sync.Cond
+	inner  io.Reader
+	closed bool
+}
+
+func NewGhostReader() GhostReader {
+	return &ghostReader{cond: sync.NewCond(new(sync.Mutex)), inner: new(waitReader)}
+}
+
+func (g *ghostReader) Swap(r io.Reader) (old io.Reader) {
+	g.cond.L.Lock()
+	old = g.inner
+	g.inner = r
+	g.cond.L.Unlock()
+	g.cond.Broadcast()
+	return old
+}
+
+func (g *ghostReader) Close() error {
+	g.cond.L.Lock()
+	g.closed = true
+	g.cond.L.Unlock()
+	g.cond.Broadcast()
+	return nil
+}
+
+func (g *ghostReader) awaitRealReader() (io.Reader, bool) {
+	// wait for a real reader
+	g.cond.L.Lock()
+	for {
+		if g.closed { // check this first
+			g.cond.L.Unlock()
+			return nil, false
+		}
+		if _, ok := g.inner.(*waitReader); ok {
+			g.cond.Wait()
+		} else {
+			break
+		}
+	}
+
+	// we don't need to serialize reads but swapping g.inner could be a race if unprotected
+	r := g.inner
+	g.cond.L.Unlock()
+	return r, true
+}
+
+func (g *ghostReader) Read(b []byte) (int, error) {
+	r, ok := g.awaitRealReader()
+	if !ok {
+		return 0, io.EOF
+	}
+
+	n, err := r.Read(b)
+	if err == io.ErrClosedPipe {
+		// NOTE: we need to mask this error so that docker does not get an error
+		// from reading the input stream and shut down the container.
+		err = nil
+	}
+	return n, err
+}
+
+// waitReader returns io.EOF if anyone calls Read. don't call Read, this is a sentinel type
+type waitReader struct{}
+
+func (e *waitReader) Read([]byte) (int, error) {
+	panic("read on waitReader should not happen")
+}
+
+// waitWriter returns io.EOF if anyone calls Write. don't call Write, this is a sentinel type
+type waitWriter struct{}
+
+func (e *waitWriter) Write([]byte) (int, error) {
+	panic("write on waitWriter should not happen")
+}

api/server/runner_test.go

@@ -3,6 +3,7 @@ package server
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -10,6 +11,7 @@ import (
 	"os"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/fnproject/fn/api/agent"
 	"github.com/fnproject/fn/api/datastore"
@@ -18,6 +20,27 @@ import (
 	"github.com/fnproject/fn/api/mqs"
 )
 
+func envTweaker(name, value string) func() {
+	bck, ok := os.LookupEnv(name)
+
+	err := os.Setenv(name, value)
+	if err != nil {
+		panic(err.Error())
+	}
+
+	return func() {
+		var err error
+		if !ok {
+			err = os.Unsetenv(name)
+		} else {
+			err = os.Setenv(name, bck)
+		}
+		if err != nil {
+			panic(err.Error())
+		}
+	}
+}
+
 func testRunner(t *testing.T, args ...interface{}) (agent.Agent, context.CancelFunc) {
 	ds := datastore.NewMock()
 	var mq models.MessageQueue = &mqs.Mock{}
@@ -123,9 +146,169 @@ func TestRouteRunnerPost(t *testing.T) {
 	}
 }
 
+func TestRouteRunnerIOPipes(t *testing.T) {
+	buf := setLogBuffer()
+	isFailure := false
+
+	// let's make freezer immediate, so that we don't deal with
+	// more timing related issues below. Slightly gains us a bit more
+	// determinism.
+	tweaker := envTweaker("FN_FREEZE_IDLE_MSECS", "0")
+	defer tweaker()
+
+	// Log once after we are done, flow of events are important (hot/cold containers, idle timeout, etc.)
+	// for figuring out why things failed.
+	defer func() {
+		if isFailure {
+			t.Log(buf.String())
+		}
+	}()
+
+	rCfg := map[string]string{"ENABLE_HEADER": "yes", "ENABLE_FOOTER": "yes"} // enable container start/end header/footer
+	rImg := "fnproject/fn-test-utils"
+
+	ds := datastore.NewMockInit(
+		[]*models.App{
+			{Name: "zoo", Config: models.Config{}},
+		},
+		[]*models.Route{
+			{Path: "/json", AppName: "zoo", Image: rImg, Type: "sync", Format: "json", Memory: 64, Timeout: 30, IdleTimeout: 30, Config: rCfg},
+			{Path: "/http", AppName: "zoo", Image: rImg, Type: "sync", Format: "http", Memory: 64, Timeout: 30, IdleTimeout: 30, Config: rCfg},
+		}, nil,
+	)
+
+	rnr, cancelrnr := testRunner(t, ds)
+	defer cancelrnr()
+
+	srv := testServer(ds, &mqs.Mock{}, ds, rnr, ServerTypeFull)
+
+	// sleep between logs and with debug enabled, fn-test-utils will log header/footer below:
+	immediateGarbage := `{"isDebug": true, "postOutGarbage": "YOGURT_YOGURT_YOGURT", "postSleepTime": 0}`
+	delayedGarbage := `{"isDebug": true, "postOutGarbage": "YOGURT_YOGURT_YOGURT", "postSleepTime": 1000}`
+	ok := `{"isDebug": true}`
+
+	//multiLogExpect := []string{"BeginOfLogs", "EndOfLogs"}
+
+	containerIds := make([]string, 0)
+
+	for i, test := range []struct {
+		path               string
+		body               string
+		method             string
+		expectedCode       int
+		expectedErrSubStr  string
+		expectedLogsSubStr []string
+		sleepAmount        time.Duration
+	}{
+		//
+		// JSON WORLD
+		//
+		// CASE I: immediate garbage: likely to be in the json decoder buffer after json resp parsing
+		{"/r/zoo/json/", immediateGarbage, "GET", http.StatusOK, "", nil, 0},
+
+		// CASE II: delayed garbage: make sure delayed output lands in between request processing, should be blocked until next req
+		{"/r/zoo/json/", delayedGarbage, "GET", http.StatusOK, "", nil, time.Second * 2},
+
+		// CASE III: normal, but should get faulty I/O from previous
+		{"/r/zoo/json/", ok, "GET", http.StatusBadGateway, "invalid json", nil, 0},
+
+		// CASE IV: should land on CASE III container
+		{"/r/zoo/json/", ok, "GET", http.StatusOK, "", nil, 0},
+
+		//
+		// HTTP WORLD
+		//
+		// CASE I: immediate garbage: should be ignored (TODO: this should test immediateGarbage case, FIX THIS)
+		{"/r/zoo/http", ok, "GET", http.StatusOK, "", nil, 0},
+
+		// CASE II: delayed garbage: make sure delayed output lands in between request processing, freezer should block,
+		// bad IO lands on next request.
+		{"/r/zoo/http", delayedGarbage, "GET", http.StatusOK, "", nil, time.Second * 2},
+
+		// CASE III: normal, but should not land on any container from case I/II.
+		{"/r/zoo/http/", ok, "GET", http.StatusBadGateway, "invalid http", nil, 0},
+
+		// CASE IV: should land on CASE III container
+		{"/r/zoo/http/", ok, "GET", http.StatusOK, "", nil, 0},
+	} {
+		body := strings.NewReader(test.body)
+		_, rec := routerRequest(t, srv.Router, test.method, test.path, body)
+		respBytes, _ := ioutil.ReadAll(rec.Body)
+		respBody := string(respBytes)
+		maxBody := len(respBody)
+		if maxBody > 1024 {
+			maxBody = 1024
+		}
+
+		containerIds = append(containerIds, "N/A")
+
+		if rec.Code != test.expectedCode {
+			isFailure = true
+			t.Errorf("Test %d: Expected status code to be %d but was %d. body: %s",
+				i, test.expectedCode, rec.Code, respBody[:maxBody])
+		}
+
+		if test.expectedErrSubStr != "" && !strings.Contains(respBody, test.expectedErrSubStr) {
+			isFailure = true
+			t.Errorf("Test %d: Expected response to include %s but got body: %s",
+				i, test.expectedErrSubStr, respBody[:maxBody])
+
+		}
+
+		if test.expectedLogsSubStr != nil {
+			callID := rec.Header().Get("Fn_call_id")
+			if !checkLogs(t, i, ds, callID, test.expectedLogsSubStr) {
+				isFailure = true
+			}
+		}
+
+		if rec.Code == http.StatusOK {
+			dockerId, err := getDockerId(respBytes)
+			if err != nil {
+				isFailure = true
+				t.Errorf("Test %d: cannot fetch docker id body: %s",
+					i, respBody[:maxBody])
+			}
+			containerIds[i] = dockerId
+		}
+
+		t.Logf("Test %d: dockerId: %v", i, containerIds[i])
+		time.Sleep(test.sleepAmount)
+	}
+
+	jsonIds := containerIds[0:4]
+
+	// now cross check JSON container ids:
+	if jsonIds[0] != jsonIds[1] &&
+		jsonIds[2] == "N/A" &&
+		jsonIds[1] != jsonIds[2] &&
+		jsonIds[2] != jsonIds[3] {
+		t.Logf("json container ids are OK, ids=%v", jsonIds)
+	} else {
+		isFailure = true
+		t.Errorf("json container ids are not OK, ids=%v", jsonIds)
+	}
+
+	httpids := containerIds[4:]
+
+	// now cross check HTTP container ids:
+	if httpids[0] == httpids[1] &&
+		httpids[2] == "N/A" &&
+		httpids[1] != httpids[2] &&
+		httpids[2] != httpids[3] {
+		t.Logf("http container ids are OK, ids=%v", httpids)
+	} else {
+		isFailure = true
+		t.Errorf("http container ids are not OK, ids=%v", httpids)
+	}
+}
+
 func TestRouteRunnerExecution(t *testing.T) {
 	buf := setLogBuffer()
 	isFailure := false
+	tweaker := envTweaker("FN_MAX_RESPONSE_SIZE", "2048")
+	defer tweaker()
+
 	// Log once after we are done, flow of events are important (hot/cold containers, idle timeout, etc.)
 	// for figuring out why things failed.
 	defer func() {
@@ -140,12 +323,6 @@ func TestRouteRunnerExecution(t *testing.T) {
 	rImgBs1 := "fnproject/imagethatdoesnotexist"
 	rImgBs2 := "localhost:5000/fnproject/imagethatdoesnotexist"
 
-	err := os.Setenv("FN_MAX_RESPONSE_SIZE", "2048")
-	if err != nil {
-		t.Errorf("Cannot set response size %v", err)
-	}
-	defer os.Setenv("FN_MAX_RESPONSE_SIZE", "")
-
 	ds := datastore.NewMockInit(
 		[]*models.App{
 			{Name: "myapp", Config: models.Config{}},
@@ -182,10 +359,10 @@ func TestRouteRunnerExecution(t *testing.T) {
 	respTypeJason := `{"jasonContentType": "foo/bar", "isDebug": true}`  // Content-Type: foo/bar
 
 	// sleep between logs and with debug enabled, fn-test-utils will log header/footer below:
-	multiLog := `{"sleepTime": 1, "isDebug": true}`
+	multiLog := `{"sleepTime": 1000, "isDebug": true}`
 	multiLogExpect := []string{"BeginOfLogs", "EndOfLogs"}
-	bigoutput := `{"sleepTime": 0, "isDebug": true, "echoContent": "repeatme", "trailerRepeat": 1000}` // 1000 trailers to exceed 2K
-	smalloutput := `{"sleepTime": 0, "isDebug": true, "echoContent": "repeatme", "trailerRepeat": 1}`  // 1 trailer < 2K
+	bigoutput := `{"isDebug": true, "echoContent": "repeatme", "trailerRepeat": 1000}` // 1000 trailers to exceed 2K
+	smalloutput := `{"isDebug": true, "echoContent": "repeatme", "trailerRepeat": 1}`  // 1 trailer < 2K
 
 	for i, test := range []struct {
 		path               string
@@ -199,17 +376,17 @@ func TestRouteRunnerExecution(t *testing.T) {
 		{"/r/myapp/", ok, "GET", http.StatusOK, expHeaders, "", nil},
 
 		{"/r/myapp/myhot", badHot, "GET", http.StatusBadGateway, expHeaders, "invalid http response", nil},
-		// hot container now back to normal, we should get OK
+		// hot container now back to normal:
 		{"/r/myapp/myhot", ok, "GET", http.StatusOK, expHeaders, "", nil},
 
+		{"/r/myapp/myhotjason", badHot, "GET", http.StatusBadGateway, expHeaders, "invalid json response", nil},
+		// hot container now back to normal:
 		{"/r/myapp/myhotjason", ok, "GET", http.StatusOK, expHeaders, "", nil},
 
 		{"/r/myapp/myhot", respTypeLie, "GET", http.StatusOK, expCTHeaders, "", nil},
 		{"/r/myapp/myhotjason", respTypeLie, "GET", http.StatusOK, expCTHeaders, "", nil},
 		{"/r/myapp/myhotjason", respTypeJason, "GET", http.StatusOK, expCTHeaders, "", nil},
 
-		{"/r/myapp/myhotjason", badHot, "GET", http.StatusBadGateway, expHeaders, "invalid json response", nil},
-
 		{"/r/myapp/myroute", ok, "GET", http.StatusOK, expHeaders, "", nil},
 		{"/r/myapp/myerror", crasher, "GET", http.StatusBadGateway, expHeaders, "container exit code 2", nil},
 		{"/r/myapp/mydne", ``, "GET", http.StatusNotFound, nil, "pull access denied", nil},
@@ -261,37 +438,69 @@ func TestRouteRunnerExecution(t *testing.T) {
 
 		if test.expectedLogsSubStr != nil {
 			callID := rec.Header().Get("Fn_call_id")
-
-			logReader, err := ds.GetLog(context.Background(), "myapp", callID)
-			if err != nil {
+			if !checkLogs(t, i, ds, callID, test.expectedLogsSubStr) {
 				isFailure = true
-				t.Errorf("Test %d: GetLog for call_id:%s returned err %s",
-					i, callID, err.Error())
-			} else {
-				logBytes, err := ioutil.ReadAll(logReader)
-				if err != nil {
-					isFailure = true
-					t.Errorf("Test %d: GetLog read IO call_id:%s returned err %s",
-						i, callID, err.Error())
-				} else {
-					logBody := string(logBytes)
-					maxLog := len(logBody)
-					if maxLog > 1024 {
-						maxLog = 1024
-					}
-					for _, match := range test.expectedLogsSubStr {
-						if !strings.Contains(logBody, match) {
-							isFailure = true
-							t.Errorf("Test %d: GetLog read IO call_id:%s cannot find: %s in logs: %s",
-								i, callID, match, logBody[:maxLog])
-						}
-					}
-				}
 			}
 		}
 	}
 }
 
+func getDockerId(respBytes []byte) (string, error) {
+
+	var respJs map[string]interface{}
+	var data map[string]interface{}
+
+	err := json.Unmarshal(respBytes, &respJs)
+	if err != nil {
+		return "", err
+	}
+
+	data, ok := respJs["data"].(map[string]interface{})
+	if !ok {
+		return "", errors.New("unexpected json: data map")
+	}
+
+	id, ok := data["DockerId"].(string)
+	if !ok {
+		return "", errors.New("unexpected json: docker id string")
+	}
+
+	return id, nil
+}
+
+func checkLogs(t *testing.T, tnum int, ds models.Datastore, callID string, expected []string) bool {
+
+	logReader, err := ds.GetLog(context.Background(), "myapp", callID)
+	if err != nil {
+		t.Errorf("Test %d: GetLog for call_id:%s returned err %s",
+			tnum, callID, err.Error())
+		return false
+	}
+
+	logBytes, err := ioutil.ReadAll(logReader)
+	if err != nil {
+		t.Errorf("Test %d: GetLog read IO call_id:%s returned err %s",
+			tnum, callID, err.Error())
+		return false
+	}
+
+	logBody := string(logBytes)
+	maxLog := len(logBody)
+	if maxLog > 1024 {
+		maxLog = 1024
+	}
+
+	for _, match := range expected {
+		if !strings.Contains(logBody, match) {
+			t.Errorf("Test %d: GetLog read IO call_id:%s cannot find: %s in logs: %s",
+				tnum, callID, match, logBody[:maxLog])
+			return false
+		}
+	}
+
+	return true
+}
+
 // implement models.MQ and models.APIError
 type errorMQ struct {
 	error

images/fn-test-utils/fn-test-utils.go

@@ -54,6 +54,12 @@ type AppRequest struct {
 	TrailerRepeat int `json:"trailerRepeat,omitempty"`
 	// corrupt http or json
 	InvalidResponse bool `json:"invalidResponse,omitempty"`
+	// if specified we 'sleep' the specified msecs *after* processing request
+	PostSleepTime int `json:"postSleepTime,omitempty"`
+	// spit this out in stdout after processing each request
+	PostOutGarbage string `json:"postOutGarbage,omitempty"`
+	// spit this out in stderr after processing each request
+	PostErrGarbage string `json:"postErrGarbage,omitempty"`
 	// TODO: simulate slow read/slow write
 	// TODO: simulate partial IO write/read
 	// TODO: simulate high cpu usage (async and sync)
@@ -101,6 +107,10 @@ func AppHandler(ctx context.Context, in io.Reader, out io.Writer) {
 	var outto fdkresponse
 	outto.Writer = out
 	finalizeRequest(&outto, req, resp)
+	err := postProcessRequest(req, out)
+	if err != nil {
+		panic(err.Error())
+	}
 }
 
 func finalizeRequest(out *fdkresponse, req *AppRequest, resp *AppResponse) {
@@ -222,6 +232,37 @@ func processRequest(ctx context.Context, in io.Reader) (*AppRequest, *AppRespons
 	return &request, &resp
 }
 
+func postProcessRequest(request *AppRequest, out io.Writer) error {
+	if request == nil {
+		return nil
+	}
+
+	if request.PostSleepTime > 0 {
+		if request.IsDebug {
+			log.Printf("PostProcess Sleeping %d", request.PostSleepTime)
+		}
+		time.Sleep(time.Duration(request.PostSleepTime) * time.Millisecond)
+	}
+
+	if request.PostOutGarbage != "" {
+		if request.IsDebug {
+			log.Printf("PostProcess PostOutGarbage %s", request.PostOutGarbage)
+		}
+
+		_, err := io.WriteString(out, request.PostOutGarbage)
+		if err != nil {
+			log.Printf("PostOutGarbage write string error %v", err)
+			return err
+		}
+	}
+
+	if request.PostErrGarbage != "" {
+		log.Printf("PostProcess PostErrGarbage %s", request.PostErrGarbage)
+	}
+
+	return nil
+}
+
 func main() {
 	if os.Getenv("ENABLE_HEADER") != "" {
 		log.Printf("Container starting")
@@ -287,6 +328,7 @@ func testDoJSONOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 	resp.Header = hdr
 
 	var jsonRequest fdkutils.JsonIn
+	var appRequest *AppRequest
 	err := json.NewDecoder(in).Decode(&jsonRequest)
 	if err != nil {
 		// stdin now closed
@@ -295,7 +337,11 @@ func testDoJSONOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 			return err
 		}
 		resp.Status = http.StatusInternalServerError
-		io.WriteString(resp, fmt.Sprintf(`{"error": %v}`, err.Error()))
+		_, err = io.WriteString(resp, fmt.Sprintf(`{"error": %v}`, err.Error()))
+		if err != nil {
+			log.Printf("json write string error %v", err)
+			return err
+		}
 	} else {
 		fdkutils.SetHeaders(ctx, jsonRequest.Protocol.Headers)
 		ctx, cancel := fdkutils.CtxWithDeadline(ctx, jsonRequest.Deadline)
@@ -308,6 +354,7 @@ func testDoJSONOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 			io.Copy(out, strings.NewReader(InvalidResponseStr))
 		}
 
+		appRequest = appReq
 	}
 
 	jsonResponse := getJSONResp(buf, &resp, &jsonRequest)
@@ -324,7 +371,7 @@ func testDoJSONOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 		return err
 	}
 
-	return nil
+	return postProcessRequest(appRequest, out)
 }
 
 // since we need to test little jason's content type since he's special. but we
@@ -355,6 +402,7 @@ func testDoHTTPOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 	resp.Status = 200
 	resp.Header = hdr
 
+	var appRequest *AppRequest
 	req, err := http.ReadRequest(bufio.NewReader(in))
 	if err != nil {
 		// stdin now closed
@@ -364,7 +412,11 @@ func testDoHTTPOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 		}
 		// TODO it would be nice if we could let the user format this response to their preferred style..
 		resp.Status = http.StatusInternalServerError
-		io.WriteString(resp, err.Error())
+		_, err = io.WriteString(resp, err.Error())
+		if err != nil {
+			log.Printf("http write string error %v", err)
+			return err
+		}
 	} else {
 		fnDeadline := fdkutils.Context(ctx).Header.Get("FN_DEADLINE")
 		ctx, cancel := fdkutils.CtxWithDeadline(ctx, fnDeadline)
@@ -378,6 +430,7 @@ func testDoHTTPOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 			io.Copy(out, strings.NewReader(InvalidResponseStr))
 		}
 
+		appRequest = appReq
 	}
 
 	hResp := fdkutils.GetHTTPResp(buf, &resp.Response, req)
@@ -388,7 +441,7 @@ func testDoHTTPOnce(ctx context.Context, in io.Reader, out io.Writer, buf *bytes
 		return err
 	}
 
-	return nil
+	return postProcessRequest(appRequest, out)
 }
 
 func getChunk(size int) []byte {