app/vmauth: allow using regexps in url_map paths

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1112

app/vmauth/README.md

@@ -65,13 +65,13 @@ users:
 
 
   # A single user for querying and inserting data:
-  # - Requests to http://vmauth:8427/api/v1/query or http://vmauth:8427/api/v1/query_range
-  #   are routed to http://vmselect:8481/select/42/prometheus.
+  # - Requests to http://vmauth:8427/api/v1/query, http://vmauth:8427/api/v1/query_range
+  #   and http://vmauth:8427/api/v1/label/<label_name>/values are routed to http://vmselect:8481/select/42/prometheus.
   #   For example, http://vmauth:8427/api/v1/query is routed to http://vmselect:8480/select/42/prometheus/api/v1/query
   # - Requests to http://vmauth:8427/api/v1/write are routed to http://vminsert:8480/insert/42/prometheus/api/v1/write
 - username: "foobar"
   url_map:
-  - src_paths: ["/api/v1/query", "/api/v1/query_range"]
+  - src_paths: ["/api/v1/query", "/api/v1/query_range", "/api/v1/label/[^/]+/values"]
     url_prefix: "http://vmselect:8481/select/42/prometheus"
   - src_paths: ["/api/v1/write"]
     url_prefix: "http://vminsert:8480/insert/42/prometheus"

app/vmauth/auth_config.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/url"
+	"regexp"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -38,8 +39,47 @@ type UserInfo struct {
 
 // URLMap is a mapping from source paths to target urls.
 type URLMap struct {
-	SrcPaths  []string `yaml:"src_paths"`
-	URLPrefix string   `yaml:"url_prefix"`
+	SrcPaths  []*SrcPath `yaml:"src_paths"`
+	URLPrefix string     `yaml:"url_prefix"`
+}
+
+// SrcPath represents an src path
+type SrcPath struct {
+	sOriginal string
+	re        *regexp.Regexp
+}
+
+func (sp *SrcPath) match(s string) bool {
+	prefix, ok := sp.re.LiteralPrefix()
+	if ok {
+		// Fast path - literal match
+		return s == prefix
+	}
+	if !strings.HasPrefix(s, prefix) {
+		return false
+	}
+	return sp.re.MatchString(s)
+}
+
+// UnmarshalYAML implements yaml.Unmarshaler
+func (sp *SrcPath) UnmarshalYAML(f func(interface{}) error) error {
+	var s string
+	if err := f(&s); err != nil {
+		return err
+	}
+	sAnchored := "^(?:" + s + ")$"
+	re, err := regexp.Compile(sAnchored)
+	if err != nil {
+		return fmt.Errorf("cannot build regexp from %q: %w", s, err)
+	}
+	sp.sOriginal = s
+	sp.re = re
+	return nil
+}
+
+// MarshalYAML implements yaml.Marshaler.
+func (sp *SrcPath) MarshalYAML() (interface{}, error) {
+	return sp.sOriginal, nil
 }
 
 func initAuthConfig() {
@@ -127,11 +167,6 @@ func parseAuthConfig(data []byte) (map[string]*UserInfo, error) {
 			if len(e.SrcPaths) == 0 {
 				return nil, fmt.Errorf("missing `src_paths`")
 			}
-			for _, path := range e.SrcPaths {
-				if !strings.HasPrefix(path, "/") {
-					return nil, fmt.Errorf("`src_path`=%q must start with `/`", path)
-				}
-			}
 			urlPrefix, err := sanitizeURLPrefix(e.URLPrefix)
 			if err != nil {
 				return nil, err

app/vmauth/auth_config_test.go

@@ -1,8 +1,12 @@
 package main
 
 import (
-	"reflect"
+	"bytes"
+	"fmt"
+	"regexp"
 	"testing"
+
+	"gopkg.in/yaml.v2"
 )
 
 func TestParseAuthConfigFailure(t *testing.T) {
@@ -79,12 +83,12 @@ users:
   - url_prefix: http://foobar
 `)
 
-	// src_path not starting with `/`
+	// Invalid regexp in src_path.
 	f(`
 users:
 - username: a
   url_map:
-  - src_paths: [foobar]
+  - src_paths: ['fo[obar']
     url_prefix: http://foobar
 `)
 }
@@ -97,8 +101,8 @@ func TestParseAuthConfigSuccess(t *testing.T) {
 			t.Fatalf("unexpected error: %s", err)
 		}
 		removeMetrics(m)
-		if !reflect.DeepEqual(m, expectedAuthConfig) {
-			t.Fatalf("unexpected auth config\ngot\n%v\nwant\n%v", m, expectedAuthConfig)
+		if err := areEqualConfigs(m, expectedAuthConfig); err != nil {
+			t.Fatal(err)
 		}
 	}
 
@@ -139,7 +143,7 @@ users:
 users:
 - username: foo
   url_map:
-  - src_paths: ["/api/v1/query","/api/v1/query_range"]
+  - src_paths: ["/api/v1/query","/api/v1/query_range","/api/v1/label/[^./]+/.+"]
     url_prefix: http://vmselect/select/0/prometheus
   - src_paths: ["/api/v1/write"]
     url_prefix: http://vminsert/insert/0/prometheus
@@ -148,11 +152,11 @@ users:
 			Username: "foo",
 			URLMap: []URLMap{
 				{
-					SrcPaths:  []string{"/api/v1/query", "/api/v1/query_range"},
+					SrcPaths:  getSrcPaths([]string{"/api/v1/query", "/api/v1/query_range", "/api/v1/label/[^./]+/.+"}),
 					URLPrefix: "http://vmselect/select/0/prometheus",
 				},
 				{
-					SrcPaths:  []string{"/api/v1/write"},
+					SrcPaths:  getSrcPaths([]string{"/api/v1/write"}),
 					URLPrefix: "http://vminsert/insert/0/prometheus",
 				},
 			},
@@ -160,8 +164,34 @@ users:
 	})
 }
 
+func getSrcPaths(paths []string) []*SrcPath {
+	var sps []*SrcPath
+	for _, path := range paths {
+		sps = append(sps, &SrcPath{
+			sOriginal: path,
+			re:        regexp.MustCompile("^(?:" + path + ")$"),
+		})
+	}
+	return sps
+}
+
 func removeMetrics(m map[string]*UserInfo) {
 	for _, info := range m {
 		info.requests = nil
 	}
 }
+
+func areEqualConfigs(a, b map[string]*UserInfo) error {
+	aData, err := yaml.Marshal(a)
+	if err != nil {
+		return fmt.Errorf("cannot marshal a: %w", err)
+	}
+	bData, err := yaml.Marshal(b)
+	if err != nil {
+		return fmt.Errorf("cannot marshal b: %w", err)
+	}
+	if !bytes.Equal(aData, bData) {
+		return fmt.Errorf("unexpected configs;\ngot\n%s\nwant\n%s", aData, bData)
+	}
+	return nil
+}

app/vmauth/target_url.go

@@ -18,8 +18,8 @@ func createTargetURL(ui *UserInfo, uOrig *url.URL) (string, error) {
 		u.Path = "/" + u.Path
 	}
 	for _, e := range ui.URLMap {
-		for _, path := range e.SrcPaths {
-			if u.Path == path {
+		for _, sp := range e.SrcPaths {
+			if sp.match(u.Path) {
 				return e.URLPrefix + u.RequestURI(), nil
 			}
 		}

app/vmauth/target_url_test.go

@@ -44,11 +44,11 @@ func TestCreateTargetURLSuccess(t *testing.T) {
 	ui := &UserInfo{
 		URLMap: []URLMap{
 			{
-				SrcPaths:  []string{"/api/v1/query"},
+				SrcPaths:  getSrcPaths([]string{"/api/v1/query"}),
 				URLPrefix: "http://vmselect/0/prometheus",
 			},
 			{
-				SrcPaths:  []string{"/api/v1/write"},
+				SrcPaths:  getSrcPaths([]string{"/api/v1/write"}),
 				URLPrefix: "http://vminsert/0/prometheus",
 			},
 		},
@@ -57,6 +57,26 @@ func TestCreateTargetURLSuccess(t *testing.T) {
 	f(ui, "/api/v1/query?query=up", "http://vmselect/0/prometheus/api/v1/query?query=up")
 	f(ui, "/api/v1/write", "http://vminsert/0/prometheus/api/v1/write")
 	f(ui, "/api/v1/query_range", "http://default-server/api/v1/query_range")
+
+	// Complex routing regexp paths in `url_map`
+	ui = &UserInfo{
+		URLMap: []URLMap{
+			{
+				SrcPaths:  getSrcPaths([]string{"/api/v1/query(_range)?", "/api/v1/label/[^/]+/values"}),
+				URLPrefix: "http://vmselect/0/prometheus",
+			},
+			{
+				SrcPaths:  getSrcPaths([]string{"/api/v1/write"}),
+				URLPrefix: "http://vminsert/0/prometheus",
+			},
+		},
+		URLPrefix: "http://default-server",
+	}
+	f(ui, "/api/v1/query?query=up", "http://vmselect/0/prometheus/api/v1/query?query=up")
+	f(ui, "/api/v1/query_range?query=up", "http://vmselect/0/prometheus/api/v1/query_range?query=up")
+	f(ui, "/api/v1/label/foo/values", "http://vmselect/0/prometheus/api/v1/label/foo/values")
+	f(ui, "/api/v1/write", "http://vminsert/0/prometheus/api/v1/write")
+	f(ui, "/api/v1/foo/bar", "http://default-server/api/v1/foo/bar")
 }
 
 func TestCreateTargetURLFailure(t *testing.T) {
@@ -78,7 +98,7 @@ func TestCreateTargetURLFailure(t *testing.T) {
 	f(&UserInfo{
 		URLMap: []URLMap{
 			{
-				SrcPaths:  []string{"/api/v1/query"},
+				SrcPaths:  getSrcPaths([]string{"/api/v1/query"}),
 				URLPrefix: "http://foobar/baz",
 			},
 		},

docs/CHANGELOG.md

@@ -7,6 +7,7 @@
   - `histogram_stdvar(buckets)` - returns standard variance for the given buckets.
   - `histogram_stddev(buckets)` - returns standard deviation for the given buckets.
 * FEATURE: vmagent: add ability to replicate scrape targets among `vmagent` instances in the cluster with `-promscrape.cluster.replicationFactor` command-line flag. See [these docs](https://victoriametrics.github.io/vmagent.html#scraping-big-number-of-targets).
+* FEATURE: vmauth: allow using regexp paths in `url_map`. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1112) for details.
 
 * BUGFIX: vmagent: reduce memory usage when Kubernetes service discovery is used in big number of distinct jobs by sharing the cache. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1113
 

docs/vmauth.md

@@ -65,13 +65,13 @@ users:
 
 
   # A single user for querying and inserting data:
-  # - Requests to http://vmauth:8427/api/v1/query or http://vmauth:8427/api/v1/query_range
-  #   are routed to http://vmselect:8481/select/42/prometheus.
+  # - Requests to http://vmauth:8427/api/v1/query, http://vmauth:8427/api/v1/query_range
+  #   and http://vmauth:8427/api/v1/label/<label_name>/values are routed to http://vmselect:8481/select/42/prometheus.
   #   For example, http://vmauth:8427/api/v1/query is routed to http://vmselect:8480/select/42/prometheus/api/v1/query
   # - Requests to http://vmauth:8427/api/v1/write are routed to http://vminsert:8480/insert/42/prometheus/api/v1/write
 - username: "foobar"
   url_map:
-  - src_paths: ["/api/v1/query", "/api/v1/query_range"]
+  - src_paths: ["/api/v1/query", "/api/v1/query_range", "/api/v1/label/[^/]+/values"]
     url_prefix: "http://vmselect:8481/select/42/prometheus"
   - src_paths: ["/api/v1/write"]
     url_prefix: "http://vminsert:8480/insert/42/prometheus"