adds query params support for vmauth urlPrefix (#1226)

* adds query params support for vmauth urlPrefix

* Update app/vmauth/example_config.yml

* Update app/vmauth/example_config.yml

Co-authored-by: Aliaksandr Valialkin <valyala@gmail.com>

app/vmauth/example_config.yml

@@ -11,6 +11,14 @@ users:
   password: "***"
   url_prefix: "http://localhost:8428"
 
+  # The user for querying local single-node VictoriaMetrics with extra_label team=dev.
+  # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
+  # will be routed to http://localhost:8428 with extra_label=team=dev query arg.
+  # For example, http://vmauth:8427/api/v1/query is routed to http://localhost:8428/api/v1/query?extra_label=team=dev
+- username: "local-single-node"
+  password: "***"
+  url_prefix: "http://localhost:8428?extra_label=team=dev"
+
   # The user for querying account 123 in VictoriaMetrics cluster
   # See https://victoriametrics.github.io/Cluster-VictoriaMetrics.html#url-format
   # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
@@ -28,4 +36,3 @@ users:
 - username: "cluster-insert-account-42"
   password: "***"
   url_prefix: "http://vminsert:8480/insert/42/prometheus"
-

app/vmauth/target_url.go

@@ -7,6 +7,32 @@ import (
 	"strings"
 )
 
+func mergeURLs(uiURL string, requestURI *url.URL) (string, error) {
+	prefixURL, err := url.Parse(uiURL)
+	if err != nil {
+		return "", fmt.Errorf("BUG - cannot parse userInfo url: %q, err: %w", uiURL, err)
+	}
+	prefixURL.Path += requestURI.Path
+	requestParams := requestURI.Query()
+	// fast path
+	if len(requestParams) == 0 {
+		return prefixURL.String(), nil
+	}
+	// merge query parameters from requests.
+	userInfoParams := prefixURL.Query()
+	for k, v := range requestParams {
+		// skip clashed query params from original request
+		if exist := userInfoParams.Get(k); len(exist) > 0 {
+			continue
+		}
+		for i := range v {
+			userInfoParams.Add(k, v[i])
+		}
+	}
+	prefixURL.RawQuery = userInfoParams.Encode()
+	return prefixURL.String(), nil
+}
+
 func createTargetURL(ui *UserInfo, uOrig *url.URL) (string, error) {
 	u, err := url.Parse(uOrig.String())
 	if err != nil {
@@ -20,12 +46,12 @@ func createTargetURL(ui *UserInfo, uOrig *url.URL) (string, error) {
 	for _, e := range ui.URLMap {
 		for _, sp := range e.SrcPaths {
 			if sp.match(u.Path) {
-				return e.URLPrefix + u.RequestURI(), nil
+				return mergeURLs(e.URLPrefix, u)
 			}
 		}
 	}
 	if len(ui.URLPrefix) > 0 {
-		return ui.URLPrefix + u.RequestURI(), nil
+		return mergeURLs(ui.URLPrefix, u)
 	}
 	return "", fmt.Errorf("missing route for %q", u)
 }

app/vmauth/target_url_test.go

@@ -38,7 +38,7 @@ func TestCreateTargetURLSuccess(t *testing.T) {
 	}, "/../../aaa", "https://sss:3894/x/y/aaa")
 	f(&UserInfo{
 		URLPrefix: "https://sss:3894/x/y",
-	}, "/./asd/../../aaa?a=d&s=s/../d", "https://sss:3894/x/y/aaa?a=d&s=s/../d")
+	}, "/./asd/../../aaa?a=d&s=s/../d", "https://sss:3894/x/y/aaa?a=d&s=s%2F..%2Fd")
 
 	// Complex routing with `url_map`
 	ui := &UserInfo{
@@ -77,6 +77,13 @@ func TestCreateTargetURLSuccess(t *testing.T) {
 	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")
+	f(&UserInfo{
+		URLPrefix: "http://foo.bar?extra_label=team=dev",
+	}, "/api/v1/query", "http://foo.bar/api/v1/query?extra_label=team=dev")
+	f(&UserInfo{
+		URLPrefix: "http://foo.bar?extra_label=team=mobile",
+	}, "/api/v1/query?extra_label=team=dev", "http://foo.bar/api/v1/query?extra_label=team%3Dmobile")
+
 }
 
 func TestCreateTargetURLFailure(t *testing.T) {