Add docker swarm test

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

config/config_test.go

@@ -31,6 +31,7 @@ import (
 	sd_config "github.com/prometheus/prometheus/discovery/config"
 	"github.com/prometheus/prometheus/discovery/consul"
 	"github.com/prometheus/prometheus/discovery/dns"
+	"github.com/prometheus/prometheus/discovery/dockerswarm"
 	"github.com/prometheus/prometheus/discovery/ec2"
 	"github.com/prometheus/prometheus/discovery/file"
 	"github.com/prometheus/prometheus/discovery/kubernetes"
@@ -605,6 +606,27 @@ var expectedConf = &Config{
 				},
 			},
 		},
+		{
+			JobName: "dockerswarm",
+
+			HonorTimestamps: true,
+			ScrapeInterval:  model.Duration(15 * time.Second),
+			ScrapeTimeout:   DefaultGlobalConfig.ScrapeTimeout,
+
+			MetricsPath: DefaultScrapeConfig.MetricsPath,
+			Scheme:      DefaultScrapeConfig.Scheme,
+
+			ServiceDiscoveryConfig: sd_config.ServiceDiscoveryConfig{
+				DockerSwarmSDConfigs: []*dockerswarm.SDConfig{
+					{
+						Host:            "http://127.0.0.1:2375",
+						Role:            "nodes",
+						Port:            80,
+						RefreshInterval: model.Duration(60 * time.Second),
+					},
+				},
+			},
+		},
 		{
 			JobName: "service-openstack",
 

config/testdata/conf.good.yml

@@ -259,6 +259,11 @@ scrape_configs:
       cert_file: valid_cert_file
       key_file: valid_key_file
 
+- job_name: dockerswarm
+  dockerswarm_sd_configs:
+  - host: http://127.0.0.1:2375
+    role: nodes
+
 - job_name: service-openstack
   openstack_sd_configs:
   - role: instance

discovery/dockerswarm/dockerswarm.go

@@ -44,7 +44,6 @@ type SDConfig struct {
 	HTTPClientConfig config_util.HTTPClientConfig `yaml:",inline"`
 
 	Host string `yaml:"host"`
-	url  *url.URL
 	Role string `yaml:"role"`
 	Port int    `yaml:"port"`
 
@@ -62,11 +61,9 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if c.Host == "" {
 		return fmt.Errorf("host missing")
 	}
-	url, err := url.Parse(c.Host)
+	if _, err = url.Parse(c.Host); err != nil {
-	if err != nil {
 		return err
 	}
-	c.url = url
 	switch c.Role {
 	case "services", "nodes", "tasks":
 	case "":
@@ -89,17 +86,15 @@ type Discovery struct {
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
 func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	var err error
+
 	d := &Discovery{
 		port: conf.Port,
 		role: conf.Role,
 	}
 
-	// This is used in tests. In normal situations, it is set when Unmarshaling.
+	hostURL, err := url.Parse(conf.Host)
-	if conf.url == nil {
+	if err != nil {
-		conf.url, err = url.Parse(conf.Host)
+		return nil, err
-		if err != nil {
-			return nil, err
-		}
 	}
 
 	opts := []client.Opt{
@@ -110,7 +105,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	// There are other protocols than HTTP supported by the Docker daemon, like
 	// unix, which are not supported by the HTTP client. Passing HTTP client
 	// options to the Docker client makes those non-HTTP requests fail.
-	if conf.url.Scheme == "http" || conf.url.Scheme == "https" {
+	if hostURL.Scheme == "http" || hostURL.Scheme == "https" {
 		rt, err := config_util.NewRoundTripperFromConfig(conf.HTTPClientConfig, "dockerswarm_sd", false)
 		if err != nil {
 			return nil, err
@@ -120,7 +115,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 				Transport: rt,
 				Timeout:   time.Duration(conf.RefreshInterval),
 			}),
-			client.WithScheme(conf.url.Scheme),
+			client.WithScheme(hostURL.Scheme),
 		)
 	}