From 29350c906ca3222b325031cd6939be79ab111a92 Mon Sep 17 00:00:00 2001
From: Madhu Venugopal <madhu@docker.com>
Date: Thu, 4 Jun 2015 04:51:16 -0700
Subject: [PATCH] Including hostdiscovery conditionaly under a build tag

In order to vendor-in libnetwork to docker, we need to remove the swarm
dependency even though it is used as library. using this PR, a new build
flag libnetwork_discovery is introduced in order to avoid pulling in the
unused hostdiscovery functionality into docker.
We are working with the Swarm project to see if we can modularize the
discovery package to become independent so that we can include them as a
vendor-in package in docker.

Signed-off-by: Madhu Venugopal <madhu@docker.com>
---
 Makefile                                |  2 +-
 hostdiscovery/hostdiscovery.go          | 18 ++--------------
 hostdiscovery/hostdiscovery_api.go      | 23 ++++++++++++++++++++
 hostdiscovery/hostdiscovery_disabled.go | 28 +++++++++++++++++++++++++
 hostdiscovery/hostdiscovery_test.go     |  2 ++
 5 files changed, 56 insertions(+), 17 deletions(-)
 create mode 100644 hostdiscovery/hostdiscovery_api.go
 create mode 100644 hostdiscovery/hostdiscovery_disabled.go

diff --git a/Makefile b/Makefile
index 59c181e..9deb265 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ build: ${build_image}.created
 	${docker} make build-local
 
 build-local:
-	$(shell which godep) go build -tags experimental ./...
+	$(shell which godep) go build -tags experimental,libnetwork_discovery ./...
 
 check: ${build_image}.created
 	${docker} make check-local
diff --git a/hostdiscovery/hostdiscovery.go b/hostdiscovery/hostdiscovery.go
index 550cb95..57a187e 100644
--- a/hostdiscovery/hostdiscovery.go
+++ b/hostdiscovery/hostdiscovery.go
@@ -1,3 +1,5 @@
+// +build libnetwork_discovery
+
 package hostdiscovery
 
 import (
@@ -24,22 +26,6 @@ import (
 
 const defaultHeartbeat = 10
 
-// JoinCallback provides a callback event for new node joining the cluster
-type JoinCallback func(entries []net.IP)
-
-// LeaveCallback provides a callback event for node leaving the cluster
-type LeaveCallback func(entries []net.IP)
-
-// HostDiscovery primary interface
-type HostDiscovery interface {
-	// StartDiscovery initiates the discovery process and provides appropriate callbacks
-	StartDiscovery(*config.ClusterCfg, JoinCallback, LeaveCallback) error
-	// StopDiscovery stops the discovery perocess
-	StopDiscovery() error
-	// Fetch returns a list of host IPs that are currently discovered
-	Fetch() ([]net.IP, error)
-}
-
 type hostDiscovery struct {
 	discovery discovery.Discovery
 	nodes     mapset.Set
diff --git a/hostdiscovery/hostdiscovery_api.go b/hostdiscovery/hostdiscovery_api.go
new file mode 100644
index 0000000..09394e0
--- /dev/null
+++ b/hostdiscovery/hostdiscovery_api.go
@@ -0,0 +1,23 @@
+package hostdiscovery
+
+import (
+	"net"
+
+	"github.com/docker/libnetwork/config"
+)
+
+// JoinCallback provides a callback event for new node joining the cluster
+type JoinCallback func(entries []net.IP)
+
+// LeaveCallback provides a callback event for node leaving the cluster
+type LeaveCallback func(entries []net.IP)
+
+// HostDiscovery primary interface
+type HostDiscovery interface {
+	// StartDiscovery initiates the discovery process and provides appropriate callbacks
+	StartDiscovery(*config.ClusterCfg, JoinCallback, LeaveCallback) error
+	// StopDiscovery stops the discovery perocess
+	StopDiscovery() error
+	// Fetch returns a list of host IPs that are currently discovered
+	Fetch() ([]net.IP, error)
+}
diff --git a/hostdiscovery/hostdiscovery_disabled.go b/hostdiscovery/hostdiscovery_disabled.go
new file mode 100644
index 0000000..2dc67cc
--- /dev/null
+++ b/hostdiscovery/hostdiscovery_disabled.go
@@ -0,0 +1,28 @@
+// +build !libnetwork_discovery
+
+package hostdiscovery
+
+import (
+	"net"
+
+	"github.com/docker/libnetwork/config"
+)
+
+type hostDiscovery struct{}
+
+// NewHostDiscovery function creates a host discovery object
+func NewHostDiscovery() HostDiscovery {
+	return &hostDiscovery{}
+}
+
+func (h *hostDiscovery) StartDiscovery(cfg *config.ClusterCfg, joinCallback JoinCallback, leaveCallback LeaveCallback) error {
+	return nil
+}
+
+func (h *hostDiscovery) StopDiscovery() error {
+	return nil
+}
+
+func (h *hostDiscovery) Fetch() ([]net.IP, error) {
+	return []net.IP{}, nil
+}
diff --git a/hostdiscovery/hostdiscovery_test.go b/hostdiscovery/hostdiscovery_test.go
index 90eca9d..43b4c82 100644
--- a/hostdiscovery/hostdiscovery_test.go
+++ b/hostdiscovery/hostdiscovery_test.go
@@ -1,3 +1,5 @@
+// +build libnetwork_discovery
+
 package hostdiscovery
 
 import (