Merge pull request #19 from tomplus/feat/tail

tail.py

README.md

@@ -1,6 +1,5 @@
 # Kubernetes Python Client
 
-![Status - under heavy development](https://img.shields.io/badge/status-%20under%20heavy%20development-red.svg)
 [![Build Status](https://travis-ci.org/tomplus/kubernetes_asyncio.svg?branch=master)](https://travis-ci.org/tomplus/kubernetes_asyncio)
 [![PyPI version](https://badge.fury.io/py/kubernetes_asyncio.svg)](https://badge.fury.io/py/kubernetes_asyncio)
 [![codecov](https://codecov.io/gh/tomplus/kubernetes_asyncio/branch/master/graph/badge.svg)](https://codecov.io/gh/tomplus/kubernetes_asyncio)
@@ -10,6 +9,8 @@ Asynchronous (AsyncIO) client library for the [Kubernetes](http://kubernetes.io/
 
 This library is created in the same way as official https://github.com/kubernetes-client/python but uses asynchronous version of swagger-codegen.
 
+My motivation: https://github.com/kubernetes-client/python/pull/324
+
 ## Installation
 
 From [PyPi](https://pypi.python.org/pypi/kubernetes_asyncio/) directly:
@@ -48,4 +49,5 @@ if __name__ == '__main__':
     loop.close()
 ```
 
-More examples you can find in `examples/` folder.
+More complicated examples, like asynchronous multiple watch or tail logs from pods,
+you can find in `examples/` folder.

examples/tail.py

@@ -0,0 +1,78 @@
+#
+# Script to print logs from container in PODs.
+#
+# Usage:
+#       python tail.py <namespace> <prefix for pods' name> [-n LINES] [-f]
+#
+# Example:
+#       python tail.py kube-system kube-dns -f
+#
+#       It will be streaming logs from all containers from PODs which name ~ "^kube-dns.*"
+#
+
+import argparse
+import asyncio
+
+from kubernetes_asyncio import client, config
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Tail for pods')
+    parser.add_argument('namespace', help="k8s namespace")
+    parser.add_argument('pod', help="pod name or prefix")
+    parser.add_argument('-f', '--follow', action='store_true',
+                        help="output appended data as the file grows")
+    parser.add_argument('-n', '--lines', default=10,
+                        help='show the last LINES lines')
+    return parser.parse_args()
+
+
+async def print_pod_log(pod, namespace, container, lines, follow):
+    v1 = client.CoreV1Api()
+    if not follow:
+        resp = await v1.read_namespaced_pod_log(pod,
+                                                namespace,
+                                                container=container,
+                                                tail_lines=lines)
+        print(resp)
+    else:
+        resp = await v1.read_namespaced_pod_log(pod,
+                                                namespace,
+                                                container=container,
+                                                tail_lines=lines,
+                                                follow=True, _preload_content=False)
+        while True:
+            line = await resp.content.readline()
+            if not line:
+                break
+            print(line.decode('utf-8'), end="")
+
+
+async def main():
+    args = parse_args()
+
+    config.load_kube_config()
+
+    v1 = client.CoreV1Api()
+    ret = await v1.list_namespaced_pod(args.namespace)
+    cmd = []
+    for pod in ret.items:
+        if pod.metadata.name.startswith(args.pod):
+            for container in pod.spec.containers:
+                cmd.append(print_pod_log(pod.metadata.name,
+                                         args.namespace,
+                                         container.name,
+                                         args.lines,
+                                         args.follow))
+
+    if cmd == []:
+        print('No matching PODs !')
+        return
+
+    await asyncio.wait(cmd)
+
+
+if __name__ == '__main__':
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(main())
+    loop.close()