Consolidate Target.Update into constructor.

The Target.Update method is no longer needed.

retrieval/target.go

@@ -185,13 +185,20 @@ type Target struct {
 
 // NewTarget creates a reasonably configured target for querying.
 func NewTarget(cfg *config.ScrapeConfig, labels, metaLabels model.LabelSet) (*Target, error) {
+	client, err := newHTTPClient(cfg)
+	if err != nil {
+		return nil, err
+	}
 	t := &Target{
 		status:          &TargetStatus{},
 		scraperStopping: make(chan struct{}),
 		scraperStopped:  make(chan struct{}),
+		scrapeConfig:    cfg,
+		labels:          labels,
+		metaLabels:      metaLabels,
+		httpClient:      client,
 	}
-	err := t.Update(cfg, labels, metaLabels)
-	return t, err
+	return t, nil
 }
 
 // Status returns the status of the target.
@@ -199,28 +206,6 @@ func (t *Target) Status() *TargetStatus {
 	return t.status
 }
 
-// Update overwrites settings in the target that are derived from the job config
-// it belongs to.
-func (t *Target) Update(cfg *config.ScrapeConfig, labels, metaLabels model.LabelSet) error {
-	t.Lock()
-
-	t.scrapeConfig = cfg
-	t.labels = labels
-	t.metaLabels = metaLabels
-
-	t.Unlock()
-
-	httpClient, err := t.client()
-	if err != nil {
-		return fmt.Errorf("cannot create HTTP client: %s", err)
-	}
-	t.Lock()
-	t.httpClient = httpClient
-	t.Unlock()
-
-	return nil
-}
-
 func newHTTPClient(cfg *config.ScrapeConfig) (*http.Client, error) {
 	tlsOpts := httputil.TLSOptions{
 		InsecureSkipVerify: cfg.TLSConfig.InsecureSkipVerify,
@@ -293,13 +278,6 @@ func (t *Target) offset(interval time.Duration) time.Duration {
 	return time.Duration(next)
 }
 
-func (t *Target) client() (*http.Client, error) {
-	t.RLock()
-	defer t.RUnlock()
-
-	return newHTTPClient(t.scrapeConfig)
-}
-
 func (t *Target) interval() time.Duration {
 	t.RLock()
 	defer t.RUnlock()

retrieval/target_test.go

@@ -578,7 +578,7 @@ func newTestTarget(targetURL string, deadline time.Duration, labels model.LabelS
 	labels[model.AddressLabel] = model.LabelValue(strings.TrimLeft(targetURL, "http://"))
 	labels[model.MetricsPathLabel] = "/metrics"
 
-	t := &Target{
+	return &Target{
 		scrapeConfig: &config.ScrapeConfig{
 			ScrapeInterval: model.Duration(time.Millisecond),
 			ScrapeTimeout:  model.Duration(deadline),
@@ -588,13 +588,6 @@ func newTestTarget(targetURL string, deadline time.Duration, labels model.LabelS
 		scraperStopping: make(chan struct{}),
 		scraperStopped:  make(chan struct{}),
 	}
-
-	var err error
-	if t.httpClient, err = t.client(); err != nil {
-		panic(err)
-	}
-
-	return t
 }
 
 func TestNewHTTPBearerToken(t *testing.T) {