Revert "support push config for InitPush (#53)"

This reverts commit 42c28a8.

Reason for revert: the provided additional public API looks not very good for future support.
See #53 (review) for details.

README.md

@@ -71,9 +71,6 @@ http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
 // ... or push registered metrics every 10 seconds to http://victoria-metrics:8428/api/v1/import/prometheus
 // with the added `instance="foobar"` label to all the pushed metrics.
 metrics.InitPush("http://victoria-metrics:8428/api/v1/import/prometheus", 10*time.Second, `instance="foobar"`, true)
-
-// ... or use metrics.PushConfig to see full list of configuration params
-// metrics.InitPushWithConfig(metrics.PushConfig{URL: "http://victoria-metrics:8428/api/v1/import/prometheus", Interval: 10*time.Second})
 ```
 
 See [docs](http://godoc.org/github.com/VictoriaMetrics/metrics) for more info.

push.go

@@ -4,8 +4,10 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
 	"net/http"
+	"net/url"
 	"time"
 
 	"compress/gzip"
@@ -88,45 +90,25 @@ func (s *Set) InitPush(pushURL string, interval time.Duration, extraLabels strin
 // in this case metrics are pushed to all the provided pushURL urls.
 //
 // It is OK calling InitPushExt multiple times with different writeMetrics -
-// in this case all the metrics generated by writeMetrics callbacks are written to pushURL.
+// in this case all the metrics generated by writeMetrics callbacks are writte to pushURL.
 func InitPushExt(pushURL string, interval time.Duration, extraLabels string, writeMetrics func(w io.Writer)) error {
-	cfg := PushConfig{
-		URL:            pushURL,
-		Interval:       interval,
-		ExtraLabels:    extraLabels,
-		WriteMetricsFn: writeMetrics,
+	if interval <= 0 {
+		return fmt.Errorf("interval must be positive; got %s", interval)
 	}
-	return InitPushWithConfig(cfg)
-}
-
-// InitPushWithConfig sets up periodic push for metrics based on params from passed PushConfig.
-//
-// It is recommended pushing metrics to /api/v1/import/prometheus endpoint according to
-// https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format
-//
-// It is OK calling InitPushWithConfig multiple times with different PushConfig.URL -
-// in this case metrics are pushed to all the provided PushConfig.URL urls.
-//
-// It is OK calling InitPushWithConfig multiple times with different PushConfig.WriteMetricsFn -
-// in this case all the metrics generated by PushConfig.WriteMetricsFn callbacks are written to PushConfig.URL.
-//
-// If
-func InitPushWithConfig(cfg PushConfig) error {
-	if err := cfg.Validate(); err != nil {
-		return fmt.Errorf("failed to validate PushConfig: %w", err)
+	if err := validateTags(extraLabels); err != nil {
+		return fmt.Errorf("invalid extraLabels=%q: %w", extraLabels, err)
 	}
-
-	writeMetrics := cfg.WriteMetricsFn
-	if writeMetrics == nil {
-		writeMetrics = func(w io.Writer) {
-			WritePrometheus(w, true)
-		}
+	pu, err := url.Parse(pushURL)
+	if err != nil {
+		return fmt.Errorf("cannot parse pushURL=%q: %w", pushURL, err)
 	}
-
-	pushURL := cfg.pushURL
-	pushURLRedacted := pushURL.Redacted()
-
-	interval := cfg.Interval
+	if pu.Scheme != "http" && pu.Scheme != "https" {
+		return fmt.Errorf("unsupported scheme in pushURL=%q; expecting 'http' or 'https'", pushURL)
+	}
+	if pu.Host == "" {
+		return fmt.Errorf("missing host in pushURL=%q", pushURL)
+	}
+	pushURLRedacted := pu.Redacted()
 	c := &http.Client{
 		Timeout: interval,
 	}
@@ -136,8 +118,6 @@ func InitPushWithConfig(cfg PushConfig) error {
 	pushDuration := pushMetrics.GetOrCreateHistogram(fmt.Sprintf(`metrics_push_duration_seconds{url=%q}`, pushURLRedacted))
 	pushBlockSize := pushMetrics.GetOrCreateHistogram(fmt.Sprintf(`metrics_push_block_size_bytes{url=%q}`, pushURLRedacted))
 	pushMetrics.GetOrCreateFloatCounter(fmt.Sprintf(`metrics_push_interval_seconds{url=%q}`, pushURLRedacted)).Set(interval.Seconds())
-
-	extraLabels := cfg.ExtraLabels
 	go func() {
 		ticker := time.NewTicker(interval)
 		var bb bytes.Buffer
@@ -166,17 +146,12 @@ func InitPushWithConfig(cfg PushConfig) error {
 			blockLen := bb.Len()
 			bytesPushedTotal.Add(blockLen)
 			pushBlockSize.Update(float64(blockLen))
-			req, err := http.NewRequest("GET", pushURL.String(), &bb)
+			req, err := http.NewRequest("GET", pushURL, &bb)
 			if err != nil {
 				panic(fmt.Errorf("BUG: metrics.push: cannot initialize request for metrics push to %q: %w", pushURLRedacted, err))
 			}
 			req.Header.Set("Content-Type", "text/plain")
 			req.Header.Set("Content-Encoding", "gzip")
-			for k, vs := range cfg.Headers {
-				for _, v := range vs {
-					req.Header.Add(k, v)
-				}
-			}
 			startTime := time.Now()
 			resp, err := c.Do(req)
 			pushDuration.UpdateDuration(startTime)
@@ -186,7 +161,7 @@ func InitPushWithConfig(cfg PushConfig) error {
 				continue
 			}
 			if resp.StatusCode/100 != 2 {
-				body, _ := io.ReadAll(resp.Body)
+				body, _ := ioutil.ReadAll(resp.Body)
 				_ = resp.Body.Close()
 				log.Printf("ERROR: metrics.push: unexpected status code in response from %q: %d; expecting 2xx; response body: %q",
 					pushURLRedacted, resp.StatusCode, body)