From 8506acbed2c07a040d02f3e595befdfadd360114 Mon Sep 17 00:00:00 2001
From: Victor Vieux <victorvieux@gmail.com>
Date: Wed, 8 Apr 2015 17:14:20 -0700
Subject: [PATCH] fix proxyRandom even without container

Signed-off-by: Victor Vieux <victorvieux@gmail.com>
---
 api/handlers.go          | 22 ++++++++--------------
 cluster/cluster.go       |  4 ++++
 cluster/swarm/cluster.go | 17 +++++++++++++++++
 3 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/api/handlers.go b/api/handlers.go
index 6621425370..65c82a0652 100644
--- a/api/handlers.go
+++ b/api/handlers.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
-	"math/rand"
 	"net/http"
 	"runtime"
 	"sort"
@@ -14,8 +13,6 @@ import (
 
 	dockerfilters "github.com/docker/docker/pkg/parsers/filters"
 	"github.com/docker/swarm/cluster"
-	"github.com/docker/swarm/scheduler/filter"
-	"github.com/docker/swarm/scheduler/node"
 	"github.com/docker/swarm/version"
 	"github.com/gorilla/mux"
 	"github.com/samalba/dockerclient"
@@ -398,24 +395,21 @@ func proxyImage(c *context, w http.ResponseWriter, r *http.Request) {
 
 // Proxy a request to a random node
 func proxyRandom(c *context, w http.ResponseWriter, r *http.Request) {
-	candidates := []*node.Node{}
-
-	// FIXME: doesn't work if there are no container in the cluster
-	// remove proxyRandom and implemente the features locally
-	for _, container := range c.cluster.Containers() {
-		candidates = append(candidates, node.NewNode(container.Engine))
-	}
-
-	healthFilter := &filter.HealthFilter{}
-	accepted, err := healthFilter.Filter(nil, candidates)
+	engine, err := c.cluster.RandomEngine_()
 	if err != nil {
 		httpError(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
-	if err := proxy(c.tlsConfig, accepted[rand.Intn(len(accepted))].Addr, w, r); err != nil {
+	if engine == nil {
+		httpError(w, "no node available in the cluster", http.StatusInternalServerError)
+		return
+	}
+
+	if err := proxy(c.tlsConfig, engine.Addr, w, r); err != nil {
 		httpError(w, err.Error(), http.StatusInternalServerError)
 	}
+
 }
 
 // POST  /commit
diff --git a/cluster/cluster.go b/cluster/cluster.go
index b258164266..5723aa9334 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -39,4 +39,8 @@ type Cluster interface {
 
 	// Register an event handler for cluster-wide events.
 	RegisterEventHandler(h EventHandler) error
+
+	// FIXME: remove this method
+	// Return a random engine
+	RandomEngine_() (*Engine, error)
 }
diff --git a/cluster/swarm/cluster.go b/cluster/swarm/cluster.go
index 7c7f4549ed..12d833ed06 100644
--- a/cluster/swarm/cluster.go
+++ b/cluster/swarm/cluster.go
@@ -3,6 +3,7 @@ package swarm
 import (
 	"errors"
 	"fmt"
+	"math/rand"
 	"sort"
 	"sync"
 
@@ -11,6 +12,7 @@ import (
 	"github.com/docker/swarm/cluster"
 	"github.com/docker/swarm/discovery"
 	"github.com/docker/swarm/scheduler"
+	"github.com/docker/swarm/scheduler/filter"
 	"github.com/docker/swarm/scheduler/node"
 	"github.com/docker/swarm/state"
 	"github.com/samalba/dockerclient"
@@ -307,3 +309,18 @@ func (c *Cluster) Info() [][2]string {
 
 	return info
 }
+
+// RandomEngine_ returns a random engine.
+func (c *Cluster) RandomEngine_() (*cluster.Engine, error) {
+	healthFilter := &filter.HealthFilter{}
+	accepted, err := healthFilter.Filter(nil, c.listNodes())
+	if err != nil {
+		return nil, err
+	}
+	if size := len(accepted); size > 0 {
+		if n, ok := c.engines[accepted[rand.Intn(size)].ID]; ok {
+			return n, nil
+		}
+	}
+	return nil, nil
+}