Added example api code showing how to add auth tokens and user agents to prom client. (#817)

* Added example api code showing how to add auth tokens and user agents to prom client.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Ran go mod tidy.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

api/prometheus/v1/example_test.go

@@ -18,11 +18,13 @@ package v1_test
 import (
 	"context"
 	"fmt"
+	"net/http"
 	"os"
 	"time"
 
 	"github.com/prometheus/client_golang/api"
 	v1 "github.com/prometheus/client_golang/api/prometheus/v1"
+	"github.com/prometheus/common/config"
 )
 
 func ExampleAPI_query() {
@@ -76,6 +78,118 @@ func ExampleAPI_queryRange() {
 	fmt.Printf("Result:\n%v\n", result)
 }
 
+type userAgentRoundTripper struct {
+	name string
+	rt   http.RoundTripper
+}
+
+// RoundTrip implements the http.RoundTripper interface.
+func (u userAgentRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
+	if r.UserAgent() == "" {
+		// The specification of http.RoundTripper says that it shouldn't mutate
+		// the request so make a copy of req.Header since this is all that is
+		// modified.
+		r2 := new(http.Request)
+		*r2 = *r
+		r2.Header = make(http.Header)
+		for k, s := range r.Header {
+			r2.Header[k] = s
+		}
+		r2.Header.Set("User-Agent", u.name)
+		r = r2
+	}
+	return u.rt.RoundTrip(r)
+}
+
+func ExampleAPI_queryRangeWithUserAgent() {
+	client, err := api.NewClient(api.Config{
+		Address:      "http://demo.robustperception.io:9090",
+		RoundTripper: userAgentRoundTripper{name: "Client-Golang", rt: api.DefaultRoundTripper},
+	})
+	if err != nil {
+		fmt.Printf("Error creating client: %v\n", err)
+		os.Exit(1)
+	}
+
+	v1api := v1.NewAPI(client)
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	r := v1.Range{
+		Start: time.Now().Add(-time.Hour),
+		End:   time.Now(),
+		Step:  time.Minute,
+	}
+	result, warnings, err := v1api.QueryRange(ctx, "rate(prometheus_tsdb_head_samples_appended_total[5m])", r)
+	if err != nil {
+		fmt.Printf("Error querying Prometheus: %v\n", err)
+		os.Exit(1)
+	}
+	if len(warnings) > 0 {
+		fmt.Printf("Warnings: %v\n", warnings)
+	}
+	fmt.Printf("Result:\n%v\n", result)
+}
+
+func ExampleAPI_queryRangeWithBasicAuth() {
+	client, err := api.NewClient(api.Config{
+		Address: "http://demo.robustperception.io:9090",
+		// We can use amazing github.com/prometheus/common/config helper!
+		RoundTripper: config.NewBasicAuthRoundTripper("me", "defintely_me", "", api.DefaultRoundTripper),
+	})
+	if err != nil {
+		fmt.Printf("Error creating client: %v\n", err)
+		os.Exit(1)
+	}
+
+	v1api := v1.NewAPI(client)
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	r := v1.Range{
+		Start: time.Now().Add(-time.Hour),
+		End:   time.Now(),
+		Step:  time.Minute,
+	}
+	result, warnings, err := v1api.QueryRange(ctx, "rate(prometheus_tsdb_head_samples_appended_total[5m])", r)
+	if err != nil {
+		fmt.Printf("Error querying Prometheus: %v\n", err)
+		os.Exit(1)
+	}
+	if len(warnings) > 0 {
+		fmt.Printf("Warnings: %v\n", warnings)
+	}
+	fmt.Printf("Result:\n%v\n", result)
+}
+
+func ExampleAPI_queryRangeWithAuthBearerToken() {
+	client, err := api.NewClient(api.Config{
+		Address: "http://demo.robustperception.io:9090",
+		// We can use amazing github.com/prometheus/common/config helper!
+		RoundTripper: config.NewBearerAuthRoundTripper("secret_token", api.DefaultRoundTripper),
+	})
+	if err != nil {
+		fmt.Printf("Error creating client: %v\n", err)
+		os.Exit(1)
+	}
+
+	v1api := v1.NewAPI(client)
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	r := v1.Range{
+		Start: time.Now().Add(-time.Hour),
+		End:   time.Now(),
+		Step:  time.Minute,
+	}
+	result, warnings, err := v1api.QueryRange(ctx, "rate(prometheus_tsdb_head_samples_appended_total[5m])", r)
+	if err != nil {
+		fmt.Printf("Error querying Prometheus: %v\n", err)
+		os.Exit(1)
+	}
+	if len(warnings) > 0 {
+		fmt.Printf("Warnings: %v\n", warnings)
+	}
+	fmt.Printf("Result:\n%v\n", result)
+}
+
 func ExampleAPI_series() {
 	client, err := api.NewClient(api.Config{
 		Address: "http://demo.robustperception.io:9090",

go.sum

@@ -143,6 +143,7 @@ github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANyt
 github.com/influxdata/influxdb1-client v0.0.0-20191209144304-8bf82d3c094d/go.mod h1:qj24IKcXYK6Iy9ceXlo3Tc+vtHo9lIhSX5JddghvEPo=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
+github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6 h1:MrUvLMLTMxbqFJ9kzlvat/rYZqZnW3u4wkLzWTaFwKs=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
@@ -189,6 +190,7 @@ github.com/modern-go/reflect2 v1.0.1 h1:9f412s+6RmYXLWZSEzVVgPGK7C2PphHj5RJrvfx9
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223 h1:F9x/1yl3T2AeKLr2AMdilSD8+f9bvMnNN8VS5iDtovc=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
+github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/nats-io/jwt v0.3.0/go.mod h1:fRYCDE99xlTsqUzISS1Bi75UBJ6ljOJQOAAu5VglpSg=
 github.com/nats-io/jwt v0.3.2/go.mod h1:/euKqTS1ZD+zzjYrY7pseZrTtWQSjujC7xjPc8wL6eU=
@@ -333,6 +335,7 @@ golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR
 golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200625001655-4c5254603344 h1:vGXIOMxbNfDTk/aXCmfdLgkrSV+Z2tcbze+pEc3v5W4=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -370,6 +373,7 @@ golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 h1:9UQO31fZ+0aKQOFldThf7BKPMJTiBfWycGh/u3UoO88=
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=