Fix for proxy exiting early

When a proxied core service was accessed before it was ready
to accept a connection, due to a start-up, restart, etc of
a core service, then the proxy exited instead of continuing
to accept new connections.

This meant having to restart faasd and hope the race condition
worked itself out, or that no incoming requests were made.

Tested with Grafana, which seemed to manifest the issue
the most.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/provider/handlers/function_list.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"log"
+	"strings"
 	"time"
 
 	"github.com/containerd/containerd"
@@ -51,7 +52,10 @@ func ListFunctions(client *containerd.Client, namespace string) (map[string]*Fun
 		name := c.ID()
 		f, err := GetFunction(client, name, namespace)
 		if err != nil {
-			log.Printf("skipping %s, error: %s", name, err)
+			if !strings.Contains(err.Error(), "unable to get IP address for container") {
+				log.Printf("List functions, skipping: %s, error: %s", name, err)
+			}
+
 		} else {
 			functions[name] = &f
 		}

pkg/proxy.go

@@ -86,7 +86,7 @@ func (p *Proxy) Start() error {
 			conn.Close()
 
 			log.Printf("Unable to dial: %s, error: %s", upstreamAddr, err.Error())
-			return err
+			continue
 		}
 
 		go pipe(conn, upstream)

pkg/service/service.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync"
 	"time"
 
@@ -45,10 +46,24 @@ func Remove(ctx context.Context, client *containerd.Client, name string) error {
 				log.Printf("Status of %s is: %s\n", name, status.Status)
 			}
 
-			log.Printf("Need to kill task: %s\n", name)
+			var gracePeriod = time.Second * 30
-			if err = killTask(ctx, t); err != nil {
+			spec, err := t.Spec(ctx)
+			if err == nil {
+				for _, p := range spec.Process.Env {
+					k, v, ok := strings.Cut(p, "=")
+					if ok && k == "grace_period" {
+						periodVal, err := time.ParseDuration(v)
+						if err == nil {
+							gracePeriod = periodVal
+						}
+					}
+				}
+			}
+
+			if err = killTask(ctx, t, gracePeriod); err != nil {
 				return fmt.Errorf("error killing task %s, %s, %w", container.ID(), name, err)
 			}
+
 		}
 
 		if err := container.Delete(ctx, containerd.WithSnapshotCleanup); err != nil {
@@ -66,14 +81,13 @@ func Remove(ctx context.Context, client *containerd.Client, name string) error {
 }
 
 // Adapted from Stellar - https://github.com/stellar
-func killTask(ctx context.Context, task containerd.Task) error {
+func killTask(ctx context.Context, task containerd.Task, gracePeriod time.Duration) error {
-
-	killTimeout := 30 * time.Second
 
 	wg := &sync.WaitGroup{}
 	wg.Add(1)
 	var err error
 
+	waited := false
 	go func() {
 		defer wg.Done()
 		if task != nil {
@@ -89,22 +103,39 @@ func killTask(ctx context.Context, task containerd.Task) error {
 
 			select {
 			case <-wait:
-				task.Delete(ctx)
+				waited = true
 				return
-			case <-time.After(killTimeout):
+			case <-time.After(gracePeriod):
+				log.Printf("Sending SIGKILL to: %s after: %s", task.ID(), gracePeriod.Round(time.Second).String())
 				if err := task.Kill(ctx, unix.SIGKILL, containerd.WithKillAll); err != nil {
-					log.Printf("error force killing container task: %s", err)
+					log.Printf("error sending SIGKILL to task: %s", err)
 				}
+
 				return
 			}
 		}
 	}()
 	wg.Wait()
 
+	if task != nil {
+		if !waited {
+			wait, err := task.Wait(ctx)
+			if err != nil {
+				log.Printf("error waiting on task after kill: %s", err)
+			}
+
+			<-wait
+		}
+
+		if _, err := task.Delete(ctx); err != nil {
+			return err
+		}
+	}
+
 	return err
 }
 
-func getResolver(ctx context.Context, configFile *configfile.ConfigFile) (remotes.Resolver, error) {
+func getResolver(configFile *configfile.ConfigFile) (remotes.Resolver, error) {
 	// credsFunc is based on https://github.com/moby/buildkit/blob/0b130cca040246d2ddf55117eeff34f546417e40/session/auth/authprovider/authprovider.go#L35
 	credFunc := func(host string) (string, string, error) {
 		if host == "registry-1.docker.io" {
@@ -139,7 +170,7 @@ func PrepareImage(ctx context.Context, client *containerd.Client, imageName, sna
 		if err != nil {
 			return nil, err
 		}
-		resolver, err = getResolver(ctx, configFile)
+		resolver, err = getResolver(configFile)
 		if err != nil {
 			return empty, err
 		}