Add incluster config support

k8sutil/__init__.py

@@ -14,3 +14,5 @@
 
 from .kube_config import load_kube_config
 from .watch import Watch
+from .incluster_config import load_incluster_config
+from .incluster_config import ConfigException

k8sutil/incluster_config.py

@@ -0,0 +1,59 @@
+# 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 k8sclient import configuration
+
+
+_SERVICE_HOST_ENV_NAME = "KUBERNETES_SERVICE_HOST"
+_SERVICE_PORT_ENV_NAME = "KUBERNETES_SERVICE_PORT"
+_SERVICE_TOKEN_FILENAME = "/var/run/secrets/kubernetes.io/serviceaccount/token"
+_SERVICE_CERT_FILENAME = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
+
+
+class ConfigException(Exception):
+    pass
+
+
+def _join_host_port(host, port):
+    """Adapted golang's net.JoinHostPort"""
+    if ':' in host or '%' in host:
+        return "[%s]:%s" % (host, str(port))
+    return "%s:%s" % (host, str(port))
+
+
+def load_incluster_config():
+    """Use the service account kubernetes gives to pods to connect to kubernetes
+    cluster. It's intended for clients that expect to be running inside a pod
+    running on kubernetes. It will raise an exception if called from a process
+    not running in a kubernetes environment."""
+    if (_SERVICE_HOST_ENV_NAME not in os.environ or
+            _SERVICE_PORT_ENV_NAME not in os.environ):
+        raise ConfigException("Service host/port is not set.")
+
+    configuration.host = ("https://" +
+                          _join_host_port(os.environ[_SERVICE_HOST_ENV_NAME],
+                                          os.environ[_SERVICE_PORT_ENV_NAME]))
+
+    if not os.path.isfile(_SERVICE_TOKEN_FILENAME):
+        raise ConfigException("Service token file does not exists.")
+
+    with open(_SERVICE_TOKEN_FILENAME, 'r') as f:
+        configuration.api_key['authorization'] = "bearer " + f.read()
+
+    if not os.path.isfile(_SERVICE_CERT_FILENAME):
+        raise ConfigException("Service certification file does not exists.")
+
+    configuration.ssl_ca_cert = _SERVICE_CERT_FILENAME