Add namespaces in knative/pkg

system/clock.go

@@ -0,0 +1,32 @@
+/*
+Copyright 2019 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package system
+
+import (
+	"time"
+)
+
+// Mockable interface for time based testing
+type Clock interface {
+	Now() time.Time
+}
+
+type RealClock struct{}
+
+func (RealClock) Now() time.Time {
+	return time.Now()
+}

system/names.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2019 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package system
+
+import (
+	"fmt"
+	"os"
+)
+
+const (
+	NamespaceEnvKey = "SYSTEM_NAMESPACE"
+)
+
+// Namespace holds the K8s namespace where our serving system
+// components run.
+func Namespace() string {
+	if ns := os.Getenv(NamespaceEnvKey); ns != "" {
+		return ns
+	}
+
+	panic(fmt.Sprintf(`The environment variable %q is not set
+
+If this is a process running on Kubernetes, then it should be using the downward
+API to initialize this variable via:
+
+  env:
+  - name: %s
+    valueFrom:
+      fieldRef:
+        fieldPath: metadata.namespace
+
+If this is a Go unit test consuming system.Namespace() then it should add the
+following import:
+
+import (
+	_ "github.com/knative/pkg/system/testing"
+)`, NamespaceEnvKey, NamespaceEnvKey))
+}

system/testing/names.go

@@ -0,0 +1,27 @@
+/*
+Copyright 2019 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testing
+
+import (
+	"os"
+
+	"github.com/knative/pkg/system"
+)
+
+func init() {
+	os.Setenv(system.NamespaceEnvKey, "knative-testing")
+}