Fix parsePostgresURL issue (grafana#1111)

* Fix parsePostgresURL issue

* Update Implementation and fix unit test

* Add nolint and fix unit test

* Update changelog

* move changelog entry to unreleased

Co-authored-by: Robert Fratto <[email protected]>

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Main (unreleased)
 
+- [BUGFIX] Fix panic when using postgres_exporter (@saputradharma)
+
 # v0.21.0 (2021-11-17)
 
 - [ENHANCEMENT] Update Cortex dependency to v1.10.0-92-g85c378182. (@rlankfo)

pkg/integrations/postgres_exporter/postgres_exporter.go

@@ -84,13 +84,24 @@ func parsePostgresURL(url string) (map[string]string, error) {
 
 	res := map[string]string{}
 
+	unescaper := strings.NewReplacer(`\'`, `'`, `\\`, `\`)
+
 	for _, keypair := range strings.Split(raw, " ") {
-		parts := strings.SplitN(keypair, "=", 1)
+		parts := strings.SplitN(keypair, "=", 2)
 		if len(parts) != 2 {
 			panic(fmt.Sprintf("unexpected keypair %s from pq", keypair))
 		}
 
-		res[parts[0]] = parts[1]
+		key := parts[0]
+		value := parts[1]
+
+		// Undo all the transformations ParseURL did: remove wrapping
+		// quotes and then unescape the escaped characters.
+		value = strings.TrimPrefix(value, "'")
+		value = strings.TrimSuffix(value, "'")
+		value = unescaper.Replace(value)
+
+		res[key] = value
 	}
 
 	return res, nil

pkg/integrations/postgres_exporter/postgres_exporter_test.go

@@ -0,0 +1,24 @@
+package postgres_exporter //nolint:golint
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_ParsePostgresURL(t *testing.T) {
+	dsn := "postgresql://linus:42secret@localhost:5432/postgres?sslmode=disable"
+	expected := map[string]string{
+		"dbname":   "postgres",
+		"host":     "localhost",
+		"password": "42secret",
+		"port":     "5432",
+		"sslmode":  "disable",
+		"user":     "linus",
+	}
+
+	actual, err := parsePostgresURL(dsn)
+	require.NoError(t, err)
+	require.Equal(t, actual, expected)
+
+}