fn: user friendly timeout handling changes (#1021)

* fn: user friendly timeout handling changes

Timeout setting in routes now means "maximum amount
of time a function can run in a container".

Total wait time for a given http request is now expected
to be handled by the client. As long as the client waits,
the LB, runner or agents will search for resources to
schedule it.

api/runnerpool/ch_placer.go

@@ -31,7 +31,7 @@ func (p *chPlacer) PlaceCall(rp RunnerPool, ctx context.Context, call RunnerCall
 	// The key is just the path in this case
 	key := call.Model().Path
 	sum64 := siphash.Hash(0, 0x4c617279426f6174, []byte(key))
-	timeout := time.After(call.LbDeadline().Sub(time.Now()))
+
 	for {
 		runners, err := rp.Runners(call)
 		if err != nil {
@@ -43,8 +43,6 @@ func (p *chPlacer) PlaceCall(rp RunnerPool, ctx context.Context, call RunnerCall
 				select {
 				case <-ctx.Done():
 					return models.ErrCallTimeoutServerBusy
-				case <-timeout:
-					return models.ErrCallTimeoutServerBusy
 				default:
 				}
 
@@ -69,8 +67,6 @@ func (p *chPlacer) PlaceCall(rp RunnerPool, ctx context.Context, call RunnerCall
 		select {
 		case <-ctx.Done():
 			return models.ErrCallTimeoutServerBusy
-		case <-timeout:
-			return models.ErrCallTimeoutServerBusy
 		case <-time.After(p.rrInterval):
 		}
 	}

api/runnerpool/naive_placer.go

@@ -25,7 +25,6 @@ func NewNaivePlacer() Placer {
 }
 
 func (sp *naivePlacer) PlaceCall(rp RunnerPool, ctx context.Context, call RunnerCall) error {
-	timeout := time.After(call.LbDeadline().Sub(time.Now()))
 
 	for {
 		runners, err := rp.Runners(call)
@@ -37,8 +36,6 @@ func (sp *naivePlacer) PlaceCall(rp RunnerPool, ctx context.Context, call Runner
 				select {
 				case <-ctx.Done():
 					return models.ErrCallTimeoutServerBusy
-				case <-timeout:
-					return models.ErrCallTimeoutServerBusy
 				default:
 				}
 
@@ -62,8 +59,6 @@ func (sp *naivePlacer) PlaceCall(rp RunnerPool, ctx context.Context, call Runner
 		select {
 		case <-ctx.Done():
 			return models.ErrCallTimeoutServerBusy
-		case <-timeout:
-			return models.ErrCallTimeoutServerBusy
 		case <-time.After(sp.rrInterval):
 		}
 	}

api/runnerpool/runner_pool.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"io"
 	"net/http"
-	"time"
 
 	"github.com/fnproject/fn/api/models"
 )
@@ -42,7 +41,6 @@ type Runner interface {
 // processed by a RunnerPool
 type RunnerCall interface {
 	SlotHashId() string
-	LbDeadline() time.Time
 	RequestBody() io.ReadCloser
 	ResponseWriter() http.ResponseWriter
 	StdErr() io.ReadWriteCloser