Docker service config and examples

cmd/config.go

@@ -44,7 +44,13 @@ func parseConfig() (*core.Config, error) {
 		Scalers: make(map[string]scaler.Scaler, 5),
 		Rules:   make([]rule.Rule, 0),
 	}
-	// Parse scalers
+
+	// check endpoint
+	if viper.GetString("endpoint") == "" {
+		return nil, fmt.Errorf("No endpoint specified")
+	}
+
+	// parse scalers
 	var scalers = viper.Sub("scalers")
 	for _, name := range scalers.AllKeys() {
 		log.Info("Add scaler [" + name + "]")
@@ -58,6 +64,14 @@ func parseConfig() (*core.Config, error) {
 				return nil, errors.New("No target specified for docker-compose scaler [" + name + "]")
 			}
 			config.Scalers[name] = scaler.NewComposeScaler(s.GetString("target"), s.GetString("config"))
+		case "docker-service":
+			if s.GetString("service") == "" {
+				return nil, errors.New("No service specified for docker-service scaler [" + name + "]")
+			}
+			config.Scalers[name] = &scaler.ServiceScaler{
+				ServiceID:    s.GetString("service"),
+				EngineSocket: viper.GetString("endpoint"),
+			}
 		case "":
 			return nil, fmt.Errorf("Unknown scaler type: %s\n", s.GetString("type"))
 		}
@@ -69,14 +83,14 @@ func parseConfig() (*core.Config, error) {
 		target := rules.Sub(r).GetString("target")
 		log.Info("Add service [" + target + "]")
 
-		// Check scaler
+		// check scaler
 		// TODO external function
 		scaler := rules.Sub(r).GetString("scaler")
 		if config.Scalers[scaler] == nil {
 			return nil, errors.New("No scaler specified for rule [" + r + "]")
 		}
 
-		// Parse rules
+		// parse rules
 		up, err := rule.Decode(rules.Sub(r).GetString("up"))
 		if err != nil {
 			return nil, errors.New(target + fmt.Sprintf(": %v up", err))
@@ -86,7 +100,7 @@ func parseConfig() (*core.Config, error) {
 			return nil, errors.New(target + fmt.Sprintf(": %v down", err))
 		}
 
-		// Pick probe
+		// pick probe
 		var p probe.Probe
 		refProbe := rules.Sub(r).GetString("probe")
 		splittedProbe := strings.Split(refProbe, ".")
@@ -111,6 +125,8 @@ func parseConfig() (*core.Config, error) {
 			p = &probe.Command{
 				Cmd: rules.Sub(r).GetString("cmd"),
 			}
+		case "mock":
+			p = &probe.DefaultScalingProbe{}
 		default:
 			return nil, errors.New("Unknown probe " + splittedProbe[0])
 		}

core/scaler/service.go

@@ -3,15 +3,16 @@ package scaler
 import (
 	"fmt"
 
+	log "github.com/Sirupsen/logrus"
 	"github.com/docker/engine-api/client"
 	"github.com/docker/engine-api/types"
 	"golang.org/x/net/context"
 )
 
 // ServiceScaler work with docker 1.12 swarm services (API 1.24)
 type ServiceScaler struct {
-	serviceID    string
-	engineSocket string
+	ServiceID    string
+	EngineSocket string
 	cli          *client.Client
 }
 
@@ -46,7 +47,7 @@ func (s *ServiceScaler) scaleService(scale func(uint64) uint64) error {
 		return err
 	}
 	ctx := context.Background()
-	service, _, err := cli.ServiceInspectWithRaw(ctx, s.serviceID)
+	service, _, err := cli.ServiceInspectWithRaw(ctx, s.ServiceID)
 	if err != nil {
 		return err
 	}
@@ -55,6 +56,7 @@ func (s *ServiceScaler) scaleService(scale func(uint64) uint64) error {
 		return fmt.Errorf("scale can only be used with replicated mode")
 	}
 	target := scale(*serviceMode.Replicated.Replicas)
+	log.Debugf("Scale "+s.ServiceID+" from %d to %d", *serviceMode.Replicated.Replicas, target)
 	serviceMode.Replicated.Replicas = &target
 
 	err = cli.ServiceUpdate(ctx, service.ID, service.Version, service.Spec, types.ServiceUpdateOptions{})
@@ -65,7 +67,7 @@ func (s *ServiceScaler) scaleService(scale func(uint64) uint64) error {
 func (s *ServiceScaler) getDocker() (cli *client.Client, err error) {
 	if s.cli == nil {
 		defaultHeaders := map[string]string{"User-Agent": "engine-api-cli-1.0"}
-		s.cli, err = client.NewClient(s.engineSocket, "v1.24", nil, defaultHeaders)
+		s.cli, err = client.NewClient(s.EngineSocket, "v1.24", nil, defaultHeaders)
 	}
 	return s.cli, err
 }

examples/docker-service/helloworld/config.yaml

@@ -0,0 +1,13 @@
+endpoint: "unix:///var/run/docker.sock"
+scalers:
+    helloworld:
+        type: "docker-service"
+        service: "helloworld"
+rules:
+    sin-scale:
+        target: "helloworld"
+        probe: "mock.default"
+        up: "> 0.5"
+        down: "< 0.5"
+        scaler: helloworld
+        refresh: 3s

examples/docker-service/helloworld/start_service.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+docker service create --replicas 1 --name helloworld alpine ping docker.com