Add load balancing support to services.

pkg/cloudprovider/cloud.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cloudprovider
+
+// CloudInterface is an abstract, pluggable interface for cloud providers
+type Interface interface {
+	// TCPLoadBalancer returns a balancer interface, or nil if none is supported.  Returns an error if one occurs.
+	TCPLoadBalancer() (TCPLoadBalancer, error)
+}
+
+type TCPLoadBalancer interface {
+	// TODO: Break this up into different interfaces (LB, etc) when we have more than one type of service
+	TCPLoadBalancerExists(name, region string) (bool, error)
+	CreateTCPLoadBalancer(name, region string, port int, hosts []string) error
+	UpdateTCPLoadBalancer(name, region string, hosts []string) error
+	DeleteTCPLoadBalancer(name, region string) error
+}

pkg/cloudprovider/doc.go

@@ -0,0 +1,20 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package cloudprovider supplies interfaces and implementations for cloud service providers
+package cloudprovider
+
+import ()

pkg/cloudprovider/gce.go

@@ -0,0 +1,164 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cloudprovider
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"code.google.com/p/goauth2/compute/serviceaccount"
+	compute "code.google.com/p/google-api-go-client/compute/v1"
+)
+
+type GCECloud struct {
+	service   *compute.Service
+	projectID string
+	zone      string
+}
+
+func getProjectAndZone() (string, string, error) {
+	client := http.Client{}
+	url := "http://metadata/computeMetadata/v1/instance/zone"
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return "", "", err
+	}
+	req.Header.Add("X-Google-Metadata-Request", "True")
+	res, err := client.Do(req)
+	if err != nil {
+		return "", "", err
+	}
+	defer res.Body.Close()
+	data, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return "", "", err
+	}
+	parts := strings.Split(string(data), "/")
+	if len(parts) != 4 {
+		return "", "", fmt.Errorf("Unexpected response: %s", string(data))
+	}
+	return parts[1], parts[3], nil
+}
+
+func NewGCECloud() (*GCECloud, error) {
+	projectID, zone, err := getProjectAndZone()
+	if err != nil {
+		return nil, err
+	}
+	client, err := serviceaccount.NewClient(&serviceaccount.Options{})
+	if err != nil {
+		return nil, err
+	}
+	svc, err := compute.New(client)
+	if err != nil {
+		return nil, err
+	}
+	return &GCECloud{
+		service:   svc,
+		projectID: projectID,
+		zone:      zone,
+	}, nil
+}
+
+func (gce *GCECloud) TCPLoadBalancer() (TCPLoadBalancer, error) {
+	return gce, nil
+}
+
+func makeHostLink(projectID, zone, host string) string {
+	ix := strings.Index(host, ".")
+	if ix != -1 {
+		host = host[:ix]
+	}
+	return fmt.Sprintf("https://www.googleapis.com/compute/v1/projects/%s/zones/%s/instances/%s",
+		projectID, zone, host)
+}
+
+func (gce *GCECloud) makeTargetPool(name, region string, hosts []string) (string, error) {
+	var instances []string
+	for _, host := range hosts {
+		instances = append(instances, makeHostLink(gce.projectID, gce.zone, host))
+	}
+	pool := &compute.TargetPool{
+		Name:      name,
+		Instances: instances,
+	}
+	_, err := gce.service.TargetPools.Insert(gce.projectID, region, pool).Do()
+	if err != nil {
+		return "", err
+	}
+	link := fmt.Sprintf("https://www.googleapis.com/compute/v1/projects/%s/regions/%s/targetPools/%s", gce.projectID, region, name)
+	return link, nil
+}
+
+func (gce *GCECloud) waitForRegionOp(op *compute.Operation, region string) error {
+	pollOp := op
+	for pollOp.Status != "DONE" {
+		var err error
+		time.Sleep(time.Second * 10)
+		pollOp, err = gce.service.RegionOperations.Get(gce.projectID, region, op.Name).Do()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (gce *GCECloud) TCPLoadBalancerExists(name, region string) (bool, error) {
+	_, err := gce.service.ForwardingRules.Get(gce.projectID, region, name).Do()
+	return false, err
+}
+
+func (gce *GCECloud) CreateTCPLoadBalancer(name, region string, port int, hosts []string) error {
+	pool, err := gce.makeTargetPool(name, region, hosts)
+	if err != nil {
+		return err
+	}
+	req := &compute.ForwardingRule{
+		Name:       name,
+		IPProtocol: "TCP",
+		PortRange:  strconv.Itoa(port),
+		Target:     pool,
+	}
+	_, err = gce.service.ForwardingRules.Insert(gce.projectID, region, req).Do()
+	return err
+}
+
+func (gce *GCECloud) UpdateTCPLoadBalancer(name, region string, hosts []string) error {
+	var refs []*compute.InstanceReference
+	for _, host := range hosts {
+		refs = append(refs, &compute.InstanceReference{host})
+	}
+	req := &compute.TargetPoolsAddInstanceRequest{
+		Instances: refs,
+	}
+
+	_, err := gce.service.TargetPools.AddInstance(gce.projectID, region, name, req).Do()
+	return err
+}
+
+func (gce *GCECloud) DeleteTCPLoadBalancer(name, region string) error {
+	_, err := gce.service.ForwardingRules.Delete(gce.projectID, region, name).Do()
+	if err != nil {
+		return err
+	}
+	_, err = gce.service.TargetPools.Delete(gce.projectID, region, name).Do()
+	return err
+}