- Add context switch to kube config loader

- Refactor kube config loader to be able to test it
- Add test for kube config loader

examples/example4.py

@@ -0,0 +1,62 @@
+# Copyright 2016 The Kubernetes 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.
+
+import os
+
+from kubernetes import client, config
+from kubernetes.client import configuration
+
+
+def main():
+    config_file = os.environ["HOME"] + '/.kube/config'
+    contexts, active_context = config.list_kube_config_contexts(config_file)
+    if not contexts:
+        print("Cannot find any context in kube-config file.")
+        return
+    contexts = [context['name'] for context in contexts]
+    active_context = active_context['name']
+    for i, context in enumerate(contexts):
+        format_str = "%d. %s"
+        if context == active_context:
+            format_str = "* " + format_str
+        print(format_str % (i, context))
+    context = input("Enter context number: ")
+    context = int(context)
+    if context not in range(len(contexts)):
+        print(
+            "Number out of range. Using default context %s." %
+            active_context)
+        context_name = active_context
+    else:
+        context_name = contexts[context]
+
+    # Configs can be set in Configuration class directly or using helper
+    # utility
+    config.load_kube_config(os.environ["HOME"] + '/.kube/config', context_name)
+
+    print("Active host is %s" % configuration.host)
+
+    v1 = client.CoreV1Api()
+    print("Listing pods with their IPs:")
+    ret = v1.list_pod_for_all_namespaces(watch=False)
+    for item in ret.items:
+        print(
+            "%s\t%s\t%s" %
+            (item.status.pod_ip,
+             item.metadata.namespace,
+             item.metadata.name))
+
+
+if __name__ == '__main__':
+    main()

kubernetes/config/__init__.py

@@ -14,4 +14,5 @@
 
 from .config_exception import ConfigException
 from .incluster_config import load_incluster_config
+from .kube_config import list_kube_config_contexts
 from .kube_config import load_kube_config