Change config regexes to full-string matches.

This anchors all regular expressions entered via the config to match a
full string vs. a substring.

THIS IS A BREAKING CHANGE!

Fixes part of https://github.com/prometheus/prometheus/issues/996

config/config.go

@@ -723,6 +723,29 @@ func (c *RelabelConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 // Regexp encapsulates a regexp.Regexp and makes it YAML marshallable.
 type Regexp struct {
 	regexp.Regexp
+	original string
+}
+
+// NewRegexp creates a new anchored Regexp and returns an error if the
+// passed-in regular expression does not compile.
+func NewRegexp(s string) (*Regexp, error) {
+	regex, err := regexp.Compile("^(?:" + s + ")$")
+	if err != nil {
+		return nil, err
+	}
+	return &Regexp{
+		Regexp:   *regex,
+		original: s,
+	}, nil
+}
+
+// MustNewRegexp works like NewRegexp, but panics if the regular expression does not compile.
+func MustNewRegexp(s string) *Regexp {
+	re, err := NewRegexp(s)
+	if err != nil {
+		panic(err)
+	}
+	return re
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -731,18 +754,18 @@ func (re *Regexp) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal(&s); err != nil {
 		return err
 	}
-	regex, err := regexp.Compile(s)
+	r, err := NewRegexp(s)
 	if err != nil {
 		return err
 	}
-	re.Regexp = *regex
+	*re = *r
 	return nil
 }
 
 // MarshalYAML implements the yaml.Marshaler interface.
 func (re *Regexp) MarshalYAML() (interface{}, error) {
 	if re != nil {
-		return re.String(), nil
+		return re.original, nil
 	}
 	return nil, nil
 }

config/config_test.go

@@ -17,7 +17,6 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"reflect"
-	"regexp"
 	"strings"
 	"testing"
 	"time"
@@ -86,7 +85,7 @@ var expectedConf = &Config{
 					SourceLabels: model.LabelNames{"job", "__meta_dns_srv_name"},
 					TargetLabel:  "job",
 					Separator:    ";",
-					Regex:        &Regexp{*regexp.MustCompile("(.*)some-[regex]$")},
+					Regex:        MustNewRegexp("(.*)some-[regex]"),
 					Replacement:  "foo-${1}",
 					Action:       RelabelReplace,
 				},
@@ -126,7 +125,7 @@ var expectedConf = &Config{
 			RelabelConfigs: []*RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"job"},
-					Regex:        &Regexp{*regexp.MustCompile("(.*)some-[regex]$")},
+					Regex:        MustNewRegexp("(.*)some-[regex]"),
 					Separator:    ";",
 					Action:       RelabelDrop,
 				},
@@ -139,7 +138,7 @@ var expectedConf = &Config{
 				},
 				{
 					SourceLabels: model.LabelNames{"__tmp_hash"},
-					Regex:        &Regexp{*regexp.MustCompile("^1$")},
+					Regex:        MustNewRegexp("1"),
 					Separator:    ";",
 					Action:       RelabelKeep,
 				},
@@ -147,7 +146,7 @@ var expectedConf = &Config{
 			MetricRelabelConfigs: []*RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"__name__"},
-					Regex:        &Regexp{*regexp.MustCompile("expensive_metric.*$")},
+					Regex:        MustNewRegexp("expensive_metric.*"),
 					Separator:    ";",
 					Action:       RelabelDrop,
 				},

config/testdata/conf.good.yml

@@ -40,7 +40,7 @@ scrape_configs:
 
   relabel_configs:
   - source_labels: [job, __meta_dns_srv_name]
-    regex:         (.*)some-[regex]$
+    regex:         (.*)some-[regex]
     target_label:  job
     replacement:   foo-${1}
     # action defaults to 'replace'
@@ -71,19 +71,19 @@ scrape_configs:
 
   relabel_configs:
   - source_labels: [job]
-    regex:         (.*)some-[regex]$
+    regex:         (.*)some-[regex]
     action:        drop
   - source_labels: [__address__]
     modulus:       8
     target_label:  __tmp_hash
     action:        hashmod
   - source_labels: [__tmp_hash]
-    regex:         ^1$
+    regex:         1
     action:        keep
 
   metric_relabel_configs:
   - source_labels: [__name__]
-    regex:         expensive_metric.*$
+    regex:         expensive_metric.*
     action:        drop
 
 - job_name: service-y

retrieval/relabel_test.go

@@ -15,7 +15,6 @@ package retrieval
 
 import (
 	"reflect"
-	"regexp"
 	"testing"
 
 	"github.com/prometheus/common/model"
@@ -38,7 +37,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("f(.*)")},
+					Regex:        config.MustNewRegexp("f(.*)"),
 					TargetLabel:  model.LabelName("d"),
 					Separator:    ";",
 					Replacement:  "ch${1}-ch${1}",
@@ -61,7 +60,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a", "b"},
-					Regex:        &config.Regexp{*regexp.MustCompile("^f(.*);(.*)r$")},
+					Regex:        config.MustNewRegexp("f(.*);(.*)r"),
 					TargetLabel:  model.LabelName("a"),
 					Separator:    ";",
 					Replacement:  "b${1}${2}m", // boobam
@@ -69,7 +68,7 @@ func TestRelabel(t *testing.T) {
 				},
 				{
 					SourceLabels: model.LabelNames{"c", "a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("(b).*b(.*)ba(.*)")},
+					Regex:        config.MustNewRegexp("(b).*b(.*)ba(.*)"),
 					TargetLabel:  model.LabelName("d"),
 					Separator:    ";",
 					Replacement:  "$1$2$2$3",
@@ -90,11 +89,11 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("o$")},
+					Regex:        config.MustNewRegexp(".*o.*"),
 					Action:       config.RelabelDrop,
 				}, {
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("f(.*)")},
+					Regex:        config.MustNewRegexp("f(.*)"),
 					TargetLabel:  model.LabelName("d"),
 					Separator:    ";",
 					Replacement:  "ch$1-ch$1",
@@ -110,7 +109,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("(b)")},
+					Regex:        config.MustNewRegexp(".*(b).*"),
 					TargetLabel:  model.LabelName("d"),
 					Separator:    ";",
 					Replacement:  "$1",
@@ -129,7 +128,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("no-match")},
+					Regex:        config.MustNewRegexp("no-match"),
 					Action:       config.RelabelDrop,
 				},
 			},
@@ -144,7 +143,22 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("no-match")},
+					Regex:        config.MustNewRegexp("f|o"),
+					Action:       config.RelabelDrop,
+				},
+			},
+			output: model.LabelSet{
+				"a": "foo",
+			},
+		},
+		{
+			input: model.LabelSet{
+				"a": "foo",
+			},
+			relabel: []*config.RelabelConfig{
+				{
+					SourceLabels: model.LabelNames{"a"},
+					Regex:        config.MustNewRegexp("no-match"),
 					Action:       config.RelabelKeep,
 				},
 			},
@@ -157,7 +171,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("^f")},
+					Regex:        config.MustNewRegexp("f.*"),
 					Action:       config.RelabelKeep,
 				},
 			},
@@ -173,7 +187,7 @@ func TestRelabel(t *testing.T) {
 			relabel: []*config.RelabelConfig{
 				{
 					SourceLabels: model.LabelNames{"a"},
-					Regex:        &config.Regexp{*regexp.MustCompile("^f")},
+					Regex:        config.MustNewRegexp("f"),
 					TargetLabel:  model.LabelName("b"),
 					Replacement:  "bar",
 					Action:       config.RelabelReplace,
@@ -213,7 +227,7 @@ func TestRelabel(t *testing.T) {
 			},
 			relabel: []*config.RelabelConfig{
 				{
-					Regex:       &config.Regexp{*regexp.MustCompile("^(b.*)")},
+					Regex:       config.MustNewRegexp("(b.*)"),
 					Replacement: "bar_${1}",
 					Action:      config.RelabelLabelMap,
 				},
@@ -235,7 +249,7 @@ func TestRelabel(t *testing.T) {
 			},
 			relabel: []*config.RelabelConfig{
 				{
-					Regex:       &config.Regexp{*regexp.MustCompile("^__meta_(my.*)")},
+					Regex:       config.MustNewRegexp("__meta_(my.*)"),
 					Replacement: "${1}",
 					Action:      config.RelabelLabelMap,
 				},

retrieval/target_test.go

@@ -23,7 +23,6 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"reflect"
-	"regexp"
 	"strings"
 	"testing"
 	"time"
@@ -181,12 +180,12 @@ func TestTargetScrapeMetricRelabelConfigs(t *testing.T) {
 	testTarget.metricRelabelConfigs = []*config.RelabelConfig{
 		{
 			SourceLabels: model.LabelNames{"__name__"},
-			Regex:        &config.Regexp{*regexp.MustCompile(".*drop.*")},
+			Regex:        config.MustNewRegexp(".*drop.*"),
 			Action:       config.RelabelDrop,
 		},
 		{
 			SourceLabels: model.LabelNames{"__name__"},
-			Regex:        &config.Regexp{*regexp.MustCompile(".*(relabel|up).*")},
+			Regex:        config.MustNewRegexp(".*(relabel|up).*"),
 			TargetLabel:  "foo",
 			Replacement:  "bar",
 			Action:       config.RelabelReplace,

retrieval/targetmanager_test.go

@@ -16,7 +16,6 @@ package retrieval
 import (
 	"net/url"
 	"reflect"
-	"regexp"
 	"testing"
 	"time"
 
@@ -219,7 +218,7 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 			{
 				// Copy out the URL parameter.
 				SourceLabels: model.LabelNames{"__param_testParam"},
-				Regex:        &config.Regexp{*regexp.MustCompile("^(.*)$")},
+				Regex:        config.MustNewRegexp("(.*)"),
 				TargetLabel:  "testParam",
 				Replacement:  "$1",
 				Action:       config.RelabelReplace,
@@ -255,7 +254,7 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 		RelabelConfigs: []*config.RelabelConfig{
 			{
 				SourceLabels: model.LabelNames{model.AddressLabel},
-				Regex:        &config.Regexp{*regexp.MustCompile(`^test\.(.*?):(.*)`)},
+				Regex:        config.MustNewRegexp(`test\.(.*?):(.*)`),
 				Replacement:  "foo.${1}:${2}",
 				TargetLabel:  model.AddressLabel,
 				Action:       config.RelabelReplace,
@@ -263,7 +262,7 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 			{
 				// Add a new label for example.* targets.
 				SourceLabels: model.LabelNames{model.AddressLabel, "boom", "foo"},
-				Regex:        &config.Regexp{*regexp.MustCompile("^example.*?-b([a-z-]+)r$")},
+				Regex:        config.MustNewRegexp("example.*?-b([a-z-]+)r"),
 				TargetLabel:  "new",
 				Replacement:  "$1",
 				Separator:    "-",
@@ -272,7 +271,7 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 			{
 				// Drop an existing label.
 				SourceLabels: model.LabelNames{"boom"},
-				Regex:        &config.Regexp{*regexp.MustCompile(".*")},
+				Regex:        config.MustNewRegexp(".*"),
 				TargetLabel:  "boom",
 				Replacement:  "",
 				Action:       config.RelabelReplace,