Add initial HTTP API tests.

This covers the /query (instant query) endpoint for now. Others to
follow.

web/api/api.go

@@ -19,11 +19,13 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/prometheus/prometheus/storage/local"
+	"github.com/prometheus/prometheus/utility"
 	"github.com/prometheus/prometheus/web/httputils"
 )
 
 // MetricsService manages the /api HTTP endpoint.
 type MetricsService struct {
+	nower   utility.Time
 	Storage local.Storage
 }
 

web/api/api_test.go

@@ -0,0 +1,144 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import (
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"regexp"
+	"testing"
+	"time"
+
+	clientmodel "github.com/prometheus/client_golang/model"
+
+	"github.com/prometheus/prometheus/storage/local"
+	"github.com/prometheus/prometheus/utility"
+)
+
+type testInstantProvider struct {
+	now time.Time
+}
+
+func (p testInstantProvider) Now() time.Time {
+	return p.now
+}
+
+// This is a bit annoying. On one hand, we have to choose a current timestamp
+// because the storage doesn't have a mocked-out time yet and would otherwise
+// immediately throw away "old" samples. On the other hand, we have to make
+// sure that the float value survives the parsing and re-formatting in the
+// query layer precisely without any change. Thus we round to seconds and then
+// add known-good digits after the decimal point which behave well in
+// parsing/re-formatting.
+var testTimestamp = clientmodel.TimestampFromTime(time.Now().Round(time.Second)).Add(124 * time.Millisecond)
+
+var testNower = utility.Time{
+	Provider: testInstantProvider{
+		now: testTimestamp.Time(),
+	},
+}
+
+func TestQuery(t *testing.T) {
+	scenarios := []struct {
+		// URL query string.
+		queryStr string
+		// Expected HTTP response status code.
+		status int
+		// Regex to match against response body.
+		bodyRe string
+	}{
+		{
+			queryStr: "",
+			status:   http.StatusOK,
+			bodyRe:   "syntax error",
+		},
+		{
+			queryStr: "expr=testmetric",
+			status:   http.StatusOK,
+			bodyRe:   `{"type":"vector","value":\[\{"metric":{"__name__":"testmetric"},"value":"0","timestamp":\d+\.\d+}\],"version":1\}`,
+		},
+		{
+			queryStr: "expr=testmetric&timestamp=" + testTimestamp.String(),
+			status:   http.StatusOK,
+			bodyRe:   `{"type":"vector","value":\[\{"metric":{"__name__":"testmetric"},"value":"0","timestamp":` + testTimestamp.String() + `}\],"version":1\}`,
+		},
+		{
+			queryStr: "expr=testmetric&timestamp=" + testTimestamp.Add(-time.Hour).String(),
+			status:   http.StatusOK,
+			bodyRe:   `{"type":"vector","value":\[\],"version":1\}`,
+		},
+		{
+			queryStr: "timestamp=invalid",
+			status:   http.StatusBadRequest,
+			bodyRe:   "invalid query timestamp",
+		},
+		{
+			queryStr: "expr=(badexpression",
+			status:   http.StatusOK,
+			bodyRe:   "syntax error",
+		},
+	}
+
+	storage, closer := local.NewTestStorage(t, 1)
+	defer closer.Close()
+	storage.Append(&clientmodel.Sample{
+		Metric: clientmodel.Metric{
+			clientmodel.MetricNameLabel: "testmetric",
+		},
+		Timestamp: testTimestamp,
+		Value:     0,
+	})
+	storage.WaitForIndexing()
+
+	api := MetricsService{
+		Storage: storage,
+	}
+	api.RegisterHandler()
+
+	server := httptest.NewServer(http.DefaultServeMux)
+	defer server.Close()
+
+	for i, s := range scenarios {
+		// Do query.
+		resp, err := http.Get(server.URL + "/api/query?" + s.queryStr)
+		if err != nil {
+			t.Fatalf("%d. Error querying API: %s", i, err)
+		}
+
+		// Check status code.
+		if resp.StatusCode != s.status {
+			t.Fatalf("%d. Unexpected status code; got %d, want %d", i, resp.StatusCode, s.status)
+		}
+
+		// Check response headers.
+		ct := resp.Header["Content-Type"]
+		if len(ct) != 1 {
+			t.Fatalf("%d. Unexpected number of 'Content-Type' headers; got %d, want 1", i, len(ct))
+		}
+		if ct[0] != "application/json" {
+			t.Fatalf("%d. Unexpected 'Content-Type' header; got %s; want %s", i, ct[0], "application/json")
+		}
+
+		// Check body.
+		b, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			t.Fatalf("%d. Error reading response body: %s", i, err)
+		}
+		re := regexp.MustCompile(s.bodyRe)
+		if !re.Match(b) {
+			t.Fatalf("%d. Body didn't match '%s'. Body: %s", i, s.bodyRe, string(b))
+		}
+	}
+}

web/api/query.go

@@ -29,6 +29,7 @@ import (
 	"github.com/prometheus/prometheus/rules"
 	"github.com/prometheus/prometheus/rules/ast"
 	"github.com/prometheus/prometheus/stats"
+	"github.com/prometheus/prometheus/utility"
 	"github.com/prometheus/prometheus/web/httputils"
 )
 
@@ -46,9 +47,9 @@ func httpJSONError(w http.ResponseWriter, err error, code int) {
 	fmt.Fprintln(w, ast.ErrorToJSON(err))
 }
 
-func parseTimestampOrNow(t string) (clientmodel.Timestamp, error) {
+func parseTimestampOrNow(t string, nower utility.Time) (clientmodel.Timestamp, error) {
 	if t == "" {
-		return clientmodel.Now(), nil
+		return clientmodel.TimestampFromTime(nower.Now()), nil
 	}
 
 	tFloat, err := strconv.ParseFloat(t, 64)
@@ -74,7 +75,7 @@ func (serv MetricsService) Query(w http.ResponseWriter, r *http.Request) {
 	params := httputils.GetQueryParams(r)
 	expr := params.Get("expr")
 
-	timestamp, err := parseTimestampOrNow(params.Get("timestamp"))
+	timestamp, err := parseTimestampOrNow(params.Get("timestamp"), serv.nower)
 	if err != nil {
 		httpJSONError(w, fmt.Errorf("invalid query timestamp %s", err), http.StatusBadRequest)
 		return
@@ -112,7 +113,7 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	end, err := parseTimestampOrNow(params.Get("end"))
+	end, err := parseTimestampOrNow(params.Get("end"), serv.nower)
 	if err != nil {
 		httpJSONError(w, fmt.Errorf("invalid query timestamp: %s", err), http.StatusBadRequest)
 		return
@@ -122,7 +123,7 @@ func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
 	// the current time as the end time. Instead, the "end" parameter should
 	// simply be omitted or set to an empty string for that case.
 	if end == 0 {
-		end = clientmodel.Now()
+		end = clientmodel.TimestampFromTime(serv.nower.Now())
 	}
 
 	exprNode, err := rules.LoadExprFromString(expr)

web/api/query_test.go

@@ -21,16 +21,16 @@ import (
 )
 
 func TestParseTimestampOrNow(t *testing.T) {
-	ts, err := parseTimestampOrNow("")
+	ts, err := parseTimestampOrNow("", testNower)
 	if err != nil {
 		t.Fatalf("err = %s; want nil", err)
 	}
-	now := clientmodel.Now()
-	if now.Sub(ts) > time.Second || now.Sub(ts) < 0 {
-		t.Fatalf("ts = %v; want %v <= ts <= %v", ts, now.Sub(ts), now)
+	now := clientmodel.TimestampFromTime(testNower.Now())
+	if !now.Equal(ts) {
+		t.Fatalf("ts = %v; want ts = %v", ts, now)
 	}
 
-	ts, err = parseTimestampOrNow("1426956073.12345")
+	ts, err = parseTimestampOrNow("1426956073.12345", testNower)
 	if err != nil {
 		t.Fatalf("err = %s; want nil", err)
 	}
@@ -39,7 +39,7 @@ func TestParseTimestampOrNow(t *testing.T) {
 		t.Fatalf("ts = %v; want %v", ts, expTS)
 	}
 
-	_, err = parseTimestampOrNow("123.45foo")
+	_, err = parseTimestampOrNow("123.45foo", testNower)
 	if err == nil {
 		t.Fatalf("err = nil; want %s", err)
 	}