Service environment (#23443)

* fix fileutils.TestFindFile on MacOS

* introduce model.ExternalServiceEnvironment

* pick license public key from external service env

* pick Stripe public key from external service env

* pick Rudder key from external service env

* configure Sentry DSN from external service env

* always log external_service_environment, Unsetenv

* clear faked BuildEnv, improve logging

* strip out unset GOTAGS

* fix Sentry tests

* simplify to just ServiceEnvironment

* relocate ServiceEnvironment in client config

* initialize CWS URLs based on service environment

* unset rudder key for boards dev

* harden service environment to avoid accidental production

* fix TestSentry again

* fix DEFAULT -> ENTERPRISE

* s/dev/test when naming playbooks rudder key

* simplify boards rudder key switch

* use uniform rudderKey variable names

* retain compatibility with existing pipeline

* reduce to just production/test

* unit test with valid test license

* simplify Playbooks telemetry initialization

* restore dev service environment

* emit ServiceEnvironment when running e2e tests

server/public/model/service_environment_test.go

@@ -0,0 +1,47 @@
+package model_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/mattermost/mattermost-server/server/public/model"
+	"github.com/stretchr/testify/require"
+)
+
+// TestGetServiceEnvironment verifies the semantics of the MM_SERVICEENVIRONMENT environment
+// variable when explicitly configured as well as when left undefined or empty.
+//
+// To guard against accidental use of production keys (especially telemetry), all development and
+// testing defaults to the test service environment, making it impossible to test the production
+// semantics at the unit test level. Validating the default, enterprise service environment is left
+// to smoketests before releasing.
+func TestGetServiceEnvironment(t *testing.T) {
+	t.Run("no env defaults to test (without production tag)", func(t *testing.T) {
+		require.Equal(t, model.ServiceEnvironmentTest, model.GetServiceEnvironment())
+	})
+	t.Run("empty string defaults to test (without production tag)", func(t *testing.T) {
+		os.Setenv("MM_SERVICEENVIRONMENT", "")
+		defer os.Unsetenv("MM_SERVICEENVIRONMENT")
+		require.Equal(t, model.ServiceEnvironmentTest, model.GetServiceEnvironment())
+	})
+	t.Run("production", func(t *testing.T) {
+		os.Setenv("MM_SERVICEENVIRONMENT", "production")
+		defer os.Unsetenv("MM_SERVICEENVIRONMENT")
+		require.Equal(t, model.ServiceEnvironmentProduction, model.GetServiceEnvironment())
+	})
+	t.Run("test", func(t *testing.T) {
+		os.Setenv("MM_SERVICEENVIRONMENT", "test")
+		defer os.Unsetenv("MM_SERVICEENVIRONMENT")
+		require.Equal(t, model.ServiceEnvironmentTest, model.GetServiceEnvironment())
+	})
+	t.Run("dev", func(t *testing.T) {
+		os.Setenv("MM_SERVICEENVIRONMENT", "dev")
+		defer os.Unsetenv("MM_SERVICEENVIRONMENT")
+		require.Equal(t, model.ServiceEnvironmentDev, model.GetServiceEnvironment())
+	})
+	t.Run("whitespace and case insensitive", func(t *testing.T) {
+		os.Setenv("MM_SERVICEENVIRONMENT", "   Test  ")
+		defer os.Unsetenv("MM_SERVICEENVIRONMENT")
+		require.Equal(t, model.ServiceEnvironmentTest, model.GetServiceEnvironment())
+	})
+}