Add ability to override config variables with env variables (#32554)

* Add ability to override config variables with env variables

* Inline checkForOverrides

* Update pkg/plugins/backendplugin/manager/plugin_settings.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/plugins/backendplugin/manager/plugin_settings.go

@@ -2,6 +2,7 @@ package manager
 
 import (
 	"fmt"
+	"os"
 	"strings"
 
 	"github.com/grafana/grafana/pkg/setting"
@@ -10,9 +11,14 @@ import (
 type pluginSettings map[string]string
 
 func (ps pluginSettings) ToEnv(prefix string, hostEnv []string) []string {
-	env := []string{}
+	var env []string
 	for k, v := range ps {
-		env = append(env, fmt.Sprintf("%s_%s=%s", prefix, strings.ToUpper(k), v))
+		key := fmt.Sprintf("%s_%s", prefix, strings.ToUpper(k))
+		if value := os.Getenv(key); value != "" {
+			v = value
+		}
+
+		env = append(env, fmt.Sprintf("%s=%s", key, v))
 	}
 
 	env = append(env, hostEnv...)

pkg/plugins/backendplugin/manager/plugin_settings_test.go

@@ -1,6 +1,7 @@
 package manager
 
 import (
+	"os"
 	"sort"
 	"testing"
 
@@ -41,5 +42,55 @@ func TestPluginSettings(t *testing.T) {
 			require.Len(t, env, 3)
 			require.EqualValues(t, []string{"GF_PLUGIN_KEY1=value1", "GF_PLUGIN_KEY2=value2", "GF_VERSION=6.7.0"}, env)
 		})
+
+		t.Run("Should override config variable with environment variable ", func(t *testing.T) {
+			_ = os.Setenv("GF_PLUGIN_KEY1", "sth")
+			t.Cleanup(func() {
+				_ = os.Unsetenv("GF_PLUGIN_KEY1")
+			})
+
+			ps := getPluginSettings("plugin", cfg)
+			env := ps.ToEnv("GF_PLUGIN", []string{"GF_VERSION=6.7.0"})
+			sort.Strings(env)
+			require.Len(t, env, 3)
+			require.EqualValues(t, []string{"GF_PLUGIN_KEY1=sth", "GF_PLUGIN_KEY2=value2", "GF_VERSION=6.7.0"}, env)
+		})
+
+		t.Run("Config variable doesn't match env variable ", func(t *testing.T) {
+			_ = os.Setenv("GF_PLUGIN_KEY3", "value3")
+			t.Cleanup(func() {
+				_ = os.Unsetenv("GF_PLUGIN_KEY3")
+			})
+
+			ps := getPluginSettings("plugin", cfg)
+			env := ps.ToEnv("GF_PLUGIN", []string{"GF_VERSION=6.7.0"})
+			sort.Strings(env)
+			require.Len(t, env, 3)
+			require.EqualValues(t, []string{"GF_PLUGIN_KEY1=value1", "GF_PLUGIN_KEY2=value2", "GF_VERSION=6.7.0"}, env)
+		})
+
+		t.Run("Should override missing config variable with environment variable ", func(t *testing.T) {
+			cfg := &setting.Cfg{
+				PluginSettings: setting.PluginSettings{
+					"plugin": map[string]string{
+						"key1": "value1",
+						"key2": "",
+					},
+				},
+			}
+
+			ps := getPluginSettings("plugin", cfg)
+			require.Len(t, ps, 2)
+
+			_ = os.Setenv("GF_PLUGIN_KEY2", "sth")
+			t.Cleanup(func() {
+				_ = os.Unsetenv("GF_PLUGIN_KEY1")
+			})
+
+			env := ps.ToEnv("GF_PLUGIN", []string{"GF_VERSION=6.7.0"})
+			sort.Strings(env)
+			require.Len(t, env, 3)
+			require.EqualValues(t, []string{"GF_PLUGIN_KEY1=value1", "GF_PLUGIN_KEY2=sth", "GF_VERSION=6.7.0"}, env)
+		})
 	})
 }