Merge branch 'master' into dev-0.10

CHANGELOG.md

@@ -1,3 +1,15 @@
+## 0.9.1 / 2018-11-03
+* [FEATURE] Add `WriteToTextfile` function to facilitate the creation of
+  *.prom files for the textfile collector of the node exporter. #489
+* [ENHANCEMENT] More descriptive error messages for inconsistent label
+  cardinality. #487
+* [ENHANCEMENT] Exposition: Use a GZIP encoder pool to avoid allocations in
+  high-frequency scrape scenarios. #366
+* [ENHANCEMENT] Exposition: Streaming serving of metrics data while encoding.
+  #482
+* [ENHANCEMENT] API client: Add a way to return the body of a 5xx response.
+  #479
+
 ## 0.9.0 / 2018-10-15
 * [CHANGE] Go1.6 is no longer supported.
 * [CHANGE] More refinements of the `Registry` consistency checks: Duplicated

VERSION

@@ -1 +1 @@
-0.9.0
+0.9.1

api/prometheus/v1/api.go

@@ -60,6 +60,8 @@ const (
 	ErrCanceled              = "canceled"
 	ErrExec                  = "execution"
 	ErrBadResponse           = "bad_response"
+	ErrServer                = "server_error"
+	ErrClient                = "client_error"
 
 	// Possible values for HealthStatus.
 	HealthGood    HealthStatus = "up"
@@ -69,8 +71,9 @@ const (
 
 // Error is an error returned by the API.
 type Error struct {
-	Type ErrorType
+	Type   ErrorType
-	Msg  string
+	Msg    string
+	Detail string
 }
 
 func (e *Error) Error() string {
@@ -460,6 +463,16 @@ func apiError(code int) bool {
 	return code == statusAPIError || code == http.StatusBadRequest
 }
 
+func errorTypeAndMsgFor(resp *http.Response) (ErrorType, string) {
+	switch resp.StatusCode / 100 {
+	case 4:
+		return ErrClient, fmt.Sprintf("client error: %d", resp.StatusCode)
+	case 5:
+		return ErrServer, fmt.Sprintf("server error: %d", resp.StatusCode)
+	}
+	return ErrBadResponse, fmt.Sprintf("bad response code %d", resp.StatusCode)
+}
+
 func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
 	resp, body, err := c.Client.Do(ctx, req)
 	if err != nil {
@@ -469,9 +482,11 @@ func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, [
 	code := resp.StatusCode
 
 	if code/100 != 2 && !apiError(code) {
+		errorType, errorMsg := errorTypeAndMsgFor(resp)
 		return resp, body, &Error{
-			Type: ErrBadResponse,
+			Type:   errorType,
-			Msg:  fmt.Sprintf("bad response code %d", resp.StatusCode),
+			Msg:    errorMsg,
+			Detail: string(body),
 		}
 	}
 

api/prometheus/v1/api_test.go

@@ -18,6 +18,7 @@ package v1
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -30,9 +31,10 @@ import (
 )
 
 type apiTest struct {
-	do    func() (interface{}, error)
+	do           func() (interface{}, error)
-	inErr error
+	inErr        error
-	inRes interface{}
+	inStatusCode int
+	inRes        interface{}
 
 	reqPath   string
 	reqParam  url.Values
@@ -75,7 +77,9 @@ func (c *apiTestClient) Do(ctx context.Context, req *http.Request) (*http.Respon
 	}
 
 	resp := &http.Response{}
-	if test.inErr != nil {
+	if test.inStatusCode != 0 {
+		resp.StatusCode = test.inStatusCode
+	} else if test.inErr != nil {
 		resp.StatusCode = statusAPIError
 	} else {
 		resp.StatusCode = http.StatusOK
@@ -194,6 +198,42 @@ func TestAPIs(t *testing.T) {
 			},
 			err: fmt.Errorf("some error"),
 		},
+		{
+			do:           doQuery("2", testTime),
+			inRes:        "some body",
+			inStatusCode: 500,
+			inErr: &Error{
+				Type:   ErrServer,
+				Msg:    "server error: 500",
+				Detail: "some body",
+			},
+
+			reqMethod: "GET",
+			reqPath:   "/api/v1/query",
+			reqParam: url.Values{
+				"query": []string{"2"},
+				"time":  []string{testTime.Format(time.RFC3339Nano)},
+			},
+			err: errors.New("server_error: server error: 500"),
+		},
+		{
+			do:           doQuery("2", testTime),
+			inRes:        "some body",
+			inStatusCode: 404,
+			inErr: &Error{
+				Type:   ErrClient,
+				Msg:    "client error: 404",
+				Detail: "some body",
+			},
+
+			reqMethod: "GET",
+			reqPath:   "/api/v1/query",
+			reqParam: url.Values{
+				"query": []string{"2"},
+				"time":  []string{testTime.Format(time.RFC3339Nano)},
+			},
+			err: errors.New("client_error: client error: 404"),
+		},
 
 		{
 			do: doQueryRange("2", Range{
@@ -498,29 +538,34 @@ func TestAPIs(t *testing.T) {
 	var tests []apiTest
 	tests = append(tests, queryTests...)
 
-	for _, test := range tests {
+	for i, test := range tests {
-		client.curTest = test
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			client.curTest = test
 
-		res, err := test.do()
+			res, err := test.do()
 
-		if test.err != nil {
+			if test.err != nil {
-			if err == nil {
+				if err == nil {
-				t.Errorf("expected error %q but got none", test.err)
+					t.Fatalf("expected error %q but got none", test.err)
-				continue
+				}
+				if err.Error() != test.err.Error() {
+					t.Errorf("unexpected error: want %s, got %s", test.err, err)
+				}
+				if apiErr, ok := err.(*Error); ok {
+					if apiErr.Detail != test.inRes {
+						t.Errorf("%q should be %q", apiErr.Detail, test.inRes)
+					}
+				}
+				return
 			}
-			if err.Error() != test.err.Error() {
+			if err != nil {
-				t.Errorf("unexpected error: want %s, got %s", test.err, err)
+				t.Fatalf("unexpected error: %s", err)
 			}
-			continue
-		}
-		if err != nil {
-			t.Errorf("unexpected error: %s", err)
-			continue
-		}
 
-		if !reflect.DeepEqual(res, test.res) {
+			if !reflect.DeepEqual(res, test.res) {
-			t.Errorf("unexpected result: want %v, got %v", test.res, res)
+				t.Errorf("unexpected result: want %v, got %v", test.res, res)
-		}
+			}
+		})
 	}
 }
 
@@ -532,10 +577,10 @@ type testClient struct {
 }
 
 type apiClientTest struct {
-	code     int
+	code         int
-	response interface{}
+	response     interface{}
-	expected string
+	expectedBody string
-	err      *Error
+	expectedErr  *Error
 }
 
 func (c *testClient) URL(ep string, args map[string]string) *url.URL {
@@ -575,98 +620,108 @@ func (c *testClient) Do(ctx context.Context, req *http.Request) (*http.Response,
 func TestAPIClientDo(t *testing.T) {
 	tests := []apiClientTest{
 		{
+			code: statusAPIError,
 			response: &apiResponse{
 				Status:    "error",
 				Data:      json.RawMessage(`null`),
 				ErrorType: ErrBadData,
 				Error:     "failed",
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadData,
 				Msg:  "failed",
 			},
-			code:     statusAPIError,
+			expectedBody: `null`,
-			expected: `null`,
 		},
 		{
+			code: statusAPIError,
 			response: &apiResponse{
 				Status:    "error",
 				Data:      json.RawMessage(`"test"`),
 				ErrorType: ErrTimeout,
 				Error:     "timed out",
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrTimeout,
 				Msg:  "timed out",
 			},
-			code:     statusAPIError,
+			expectedBody: `test`,
-			expected: `test`,
 		},
 		{
-			response: "bad json",
+			code:     http.StatusInternalServerError,
-			err: &Error{
+			response: "500 error details",
-				Type: ErrBadResponse,
+			expectedErr: &Error{
-				Msg:  "bad response code 500",
+				Type:   ErrServer,
+				Msg:    "server error: 500",
+				Detail: "500 error details",
 			},
-			code: http.StatusInternalServerError,
 		},
 		{
+			code:     http.StatusNotFound,
+			response: "404 error details",
+			expectedErr: &Error{
+				Type:   ErrClient,
+				Msg:    "client error: 404",
+				Detail: "404 error details",
+			},
+		},
+		{
+			code: http.StatusBadRequest,
 			response: &apiResponse{
 				Status:    "error",
 				Data:      json.RawMessage(`null`),
 				ErrorType: ErrBadData,
 				Error:     "end timestamp must not be before start time",
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadData,
 				Msg:  "end timestamp must not be before start time",
 			},
-			code: http.StatusBadRequest,
 		},
 		{
+			code:     statusAPIError,
 			response: "bad json",
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadResponse,
 				Msg:  "invalid character 'b' looking for beginning of value",
 			},
-			code: statusAPIError,
 		},
 		{
+			code: statusAPIError,
 			response: &apiResponse{
 				Status: "success",
 				Data:   json.RawMessage(`"test"`),
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadResponse,
 				Msg:  "inconsistent body for response code",
 			},
-			code: statusAPIError,
 		},
 		{
+			code: statusAPIError,
 			response: &apiResponse{
 				Status:    "success",
 				Data:      json.RawMessage(`"test"`),
 				ErrorType: ErrTimeout,
 				Error:     "timed out",
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadResponse,
 				Msg:  "inconsistent body for response code",
 			},
-			code: statusAPIError,
 		},
 		{
+			code: http.StatusOK,
 			response: &apiResponse{
 				Status:    "error",
 				Data:      json.RawMessage(`"test"`),
 				ErrorType: ErrTimeout,
 				Error:     "timed out",
 			},
-			err: &Error{
+			expectedErr: &Error{
 				Type: ErrBadResponse,
 				Msg:  "inconsistent body for response code",
 			},
-			code: http.StatusOK,
 		},
 	}
 
@@ -677,30 +732,37 @@ func TestAPIClientDo(t *testing.T) {
 	}
 	client := &apiClient{tc}
 
-	for _, test := range tests {
+	for i, test := range tests {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
 
-		tc.ch <- test
+			tc.ch <- test
 
-		_, body, err := client.Do(context.Background(), tc.req)
+			_, body, err := client.Do(context.Background(), tc.req)
 
-		if test.err != nil {
+			if test.expectedErr != nil {
-			if err == nil {
+				if err == nil {
-				t.Errorf("expected error %q but got none", test.err)
+					t.Fatalf("expected error %q but got none", test.expectedErr)
-				continue
+				}
+				if test.expectedErr.Error() != err.Error() {
+					t.Errorf("unexpected error: want %q, got %q", test.expectedErr, err)
+				}
+				if test.expectedErr.Detail != "" {
+					apiErr := err.(*Error)
+					if apiErr.Detail != test.expectedErr.Detail {
+						t.Errorf("unexpected error details: want %q, got %q", test.expectedErr.Detail, apiErr.Detail)
+					}
+				}
+				return
 			}
-			if test.err.Error() != err.Error() {
+			if err != nil {
-				t.Errorf("unexpected error: want %q, got %q", test.err, err)
+				t.Fatalf("unexpeceted error %s", err)
 			}
-			continue
-		}
-		if err != nil {
-			t.Errorf("unexpeceted error %s", err)
-			continue
-		}
 
-		want, got := test.expected, string(body)
+			want, got := test.expectedBody, string(body)
-		if want != got {
+			if want != got {
-			t.Errorf("unexpected body: want %q, got %q", want, got)
+				t.Errorf("unexpected body: want %q, got %q", want, got)
-		}
+			}
+		})
+
 	}
 }

prometheus/counter.go

@@ -136,7 +136,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	return &CounterVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(errInconsistentCardinality)
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
 			}
 			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.

prometheus/examples_test.go

@@ -264,7 +264,7 @@ func ExampleRegister() {
 	// taskCounter unregistered.
 	// taskCounterVec not registered: a previously registered descriptor with the same fully-qualified name as Desc{fqName: "worker_pool_completed_tasks_total", help: "Total number of tasks completed.", constLabels: {}, variableLabels: [worker_id]} has different label names or a different help string
 	// taskCounterVec registered.
-	// Worker initialization failed: inconsistent label cardinality
+	// Worker initialization failed: inconsistent label cardinality: expected 1 label values but got 2 in []string{"42", "spurious arg"}
 	// notMyCounter is nil.
 	// taskCounterForWorker42 registered.
 	// taskCounterForWorker2001 registered.

prometheus/gauge.go

@@ -147,7 +147,7 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	return &GaugeVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(errInconsistentCardinality)
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
 			}
 			result := &gauge{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.

prometheus/histogram.go

@@ -165,7 +165,7 @@ func NewHistogram(opts HistogramOpts) Histogram {
 
 func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogram {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {

prometheus/labels.go

@@ -37,9 +37,22 @@ const reservedLabelPrefix = "__"
 
 var errInconsistentCardinality = errors.New("inconsistent label cardinality")
 
+func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
+	return fmt.Errorf(
+		"%s: %q has %d variable labels named %q but %d values %q were provided",
+		errInconsistentCardinality, fqName,
+		len(labels), labels,
+		len(labelValues), labelValues,
+	)
+}
+
 func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 	if len(labels) != expectedNumberOfValues {
-		return errInconsistentCardinality
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(labels), labels,
+		)
 	}
 
 	for name, val := range labels {
@@ -53,7 +66,11 @@ func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 
 func validateLabelValues(vals []string, expectedNumberOfValues int) error {
 	if len(vals) != expectedNumberOfValues {
-		return errInconsistentCardinality
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(vals), vals,
+		)
 	}
 
 	for _, val := range vals {

prometheus/registry.go

@@ -16,6 +16,9 @@ package prometheus
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"runtime"
 	"sort"
 	"strings"
@@ -23,6 +26,7 @@ import (
 	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/expfmt"
 
 	dto "github.com/prometheus/client_model/go"
 
@@ -533,6 +537,38 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
+// WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
+// Prometheus text format, and writes it to a temporary file. Upon success, the
+// temporary file is renamed to the provided filename.
+//
+// This is intended for use with the textfile collector of the node exporter.
+// Note that the node exporter expects the filename to be suffixed with ".prom".
+func WriteToTextfile(filename string, g Gatherer) error {
+	tmp, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmp.Name())
+
+	mfs, err := g.Gather()
+	if err != nil {
+		return err
+	}
+	for _, mf := range mfs {
+		if _, err := expfmt.MetricFamilyToText(tmp, mf); err != nil {
+			return err
+		}
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+
+	if err := os.Chmod(tmp.Name(), 0644); err != nil {
+		return err
+	}
+	return os.Rename(tmp.Name(), filename)
+}
+
 // processMetric is an internal helper method only used by the Gather method.
 func processMetric(
 	metric Metric,

prometheus/registry_test.go

@@ -21,9 +21,11 @@ package prometheus_test
 
 import (
 	"bytes"
+	"io/ioutil"
 	"math/rand"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"sync"
 	"testing"
 	"time"
@@ -872,3 +874,102 @@ func TestHistogramVecRegisterGatherConcurrency(t *testing.T) {
 	close(quit)
 	wg.Wait()
 }
+
+func TestWriteToTextfile(t *testing.T) {
+	expectedOut := `# HELP test_counter test counter
+# TYPE test_counter counter
+test_counter{name="qux"} 1
+# HELP test_gauge test gauge
+# TYPE test_gauge gauge
+test_gauge{name="baz"} 1.1
+# HELP test_hist test histogram
+# TYPE test_hist histogram
+test_hist_bucket{name="bar",le="0.005"} 0
+test_hist_bucket{name="bar",le="0.01"} 0
+test_hist_bucket{name="bar",le="0.025"} 0
+test_hist_bucket{name="bar",le="0.05"} 0
+test_hist_bucket{name="bar",le="0.1"} 0
+test_hist_bucket{name="bar",le="0.25"} 0
+test_hist_bucket{name="bar",le="0.5"} 0
+test_hist_bucket{name="bar",le="1"} 1
+test_hist_bucket{name="bar",le="2.5"} 1
+test_hist_bucket{name="bar",le="5"} 2
+test_hist_bucket{name="bar",le="10"} 2
+test_hist_bucket{name="bar",le="+Inf"} 2
+test_hist_sum{name="bar"} 3.64
+test_hist_count{name="bar"} 2
+# HELP test_summary test summary
+# TYPE test_summary summary
+test_summary{name="foo",quantile="0.5"} 10
+test_summary{name="foo",quantile="0.9"} 20
+test_summary{name="foo",quantile="0.99"} 20
+test_summary_sum{name="foo"} 30
+test_summary_count{name="foo"} 2
+`
+
+	registry := prometheus.NewRegistry()
+
+	summary := prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Name: "test_summary",
+			Help: "test summary",
+		},
+		[]string{"name"},
+	)
+
+	histogram := prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name: "test_hist",
+			Help: "test histogram",
+		},
+		[]string{"name"},
+	)
+
+	gauge := prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "test_gauge",
+			Help: "test gauge",
+		},
+		[]string{"name"},
+	)
+
+	counter := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "test_counter",
+			Help: "test counter",
+		},
+		[]string{"name"},
+	)
+
+	registry.MustRegister(summary)
+	registry.MustRegister(histogram)
+	registry.MustRegister(gauge)
+	registry.MustRegister(counter)
+
+	summary.With(prometheus.Labels{"name": "foo"}).Observe(10)
+	summary.With(prometheus.Labels{"name": "foo"}).Observe(20)
+	histogram.With(prometheus.Labels{"name": "bar"}).Observe(0.93)
+	histogram.With(prometheus.Labels{"name": "bar"}).Observe(2.71)
+	gauge.With(prometheus.Labels{"name": "baz"}).Set(1.1)
+	counter.With(prometheus.Labels{"name": "qux"}).Inc()
+
+	tmpfile, err := ioutil.TempFile("", "prom_registry_test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(tmpfile.Name())
+
+	if err := prometheus.WriteToTextfile(tmpfile.Name(), registry); err != nil {
+		t.Fatal(err)
+	}
+
+	fileBytes, err := ioutil.ReadFile(tmpfile.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	fileContents := string(fileBytes)
+
+	if fileContents != expectedOut {
+		t.Error("file contents didn't match unexpected")
+	}
+}

prometheus/summary.go

@@ -168,7 +168,7 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {