EventWatcher: upgrade to be version independent of docker python module

This change also cleans up host entries for all docker containers
upon exit until run in the "one shot" mode (-o)

Change-Id: I5924512ab61c1f67e0d921c69e83f0708a34cf1e

1 files changed, 61 insertions, 31 deletions

diff --git a/hostsdns/event-watcher.py b/hostsdns/event-watcher.py
index 3446777..4158ba2 100755
--- a/hostsdns/event-watcher.py
+++ b/hostsdns/event-watcher.py
@@ -3,8 +3,22 @@
 import os, sys, json, re
 import docker
 import argparse
+import atexit
 
-parser = argparse.ArgumentParser( description="Manage host entries for docker containers")
+def get_name(cobj):
+    return re.sub('^/', '', cobj["Names"][0])
+
+def find_by_id(id):
+    for c in client.containers():
+        if c.has_key("Id") and c["Id"] == id:
+            return c
+
+def find_by_name(name):
+    for c in client.containers():
+        if "/%s" % name in c["Names"]:
+            return c
+
+parser = argparse.ArgumentParser(description="Manage host entries for docker containers")
 parser.add_argument('-n', '--native', help='run service on docker host', action='store_true' , dest='NATIVE_MODE')
 parser.add_argument('-o','-1', '--once', help='run once and exit (no continuous polling)', action='store_true', dest='ONCE_MODE')
 args = parser.parse_args()
@@ -16,30 +30,34 @@ else:
     print "Running in native mode... reading from /etc/hosts"
     HOSTS_FILE="/etc/hosts"
 
-if os.environ.get("DOCKER_HOST"):
-    client = docker.from_env()
-else:
-    try:
-        client = docker.DockerClient(base_url='unix://var/run/docker.sock')
-    except:
-        print "Sorry, I can't find a dockerd to connect to."
-        sys.exit(1)
+try:
+    # version dependent.  If it's pre 2.0, then we have to use the lower
+    # level APIClient class, but in version 1.x APIClient was the base
+    if int(docker.__version__.split('.')[0]) > 1:
+        client = docker.APIClient( base_url='unix://var/run/docker.sock')
+    else:
+        client = docker.from_env()
+except:
+    print "Sorry, I can't find a dockerd to connect to."
+    sys.exit(1)
 
 def get_ip(c):
     try:
-        networks = c.attrs.get("NetworkSettings").get("Networks")
+        networks = c["NetworkSettings"]["Networks"]
 
         for n in networks:
             ip = networks[n]["IPAddress"]
             if ip is not None:
                 return ip
-    except:
+
+    except Exception as e:
+        print e
         return None
 
 def get_aliases(c):
     aliases = []
     try:
-        envs = c.attrs.get("Config").get("Env")
+        envs = client.inspect_container(c)["Config"]["Env"]
 
         for e in envs:
             m = re.match('ALIAS=(?P<aliases>.*)', e)
@@ -48,32 +66,37 @@ def get_aliases(c):
                     aliases.append(a)
         return aliases
     except KeyError as e:
+        print e
         return None
 
 def event_remove(event):
-    container = client.containers.get(event.get("id"))
-    container_remove(container.name)
+    container = find_by_id(event["id"])
+    if container is not None:
+        container_remove(get_name(container))
 
 def event_add(event):
-    container = client.containers.get(event.get("id"))
-    container_add(container.name)
+    container = find_by_id(event["id"])
+    container_add(get_name(container))
 
 def container_add(name):
     try:
-        container = client.containers.get(name)
-    except:
+        container = find_by_name(name)
+    except Exception as e:
+        print e
         return
 
-    container_remove(container.name)
+    container_remove(name)
     ip = get_ip(container)
     if ip:
-        entry = "%s %s" % (ip, container.name)
+        entry = "%s %s" % (ip, name)
         aliases = get_aliases(container)
         if aliases:
             entry += " %s" % ' '.join(aliases)
 
         open(HOSTS_FILE, 'a').write(entry+'\n')
         print "Added: %s" % entry
+    else:
+        print "WHUPS!!!!  No IP found for %s" % name
 
 def container_remove(name):
     if name is None and len(name) > 0:
@@ -87,25 +110,32 @@ def container_remove(name):
         if re.match(entry, line) is None:
             outfile.write(line)
     outfile.close()
-
     print "removed entry for pattern %s" % name
 
+def cleanup():
+    for container in client.containers():
+        container_remove(get_name(container))
+if not args.ONCE_MODE:
+    atexit.register(cleanup)
 
 ### Let's start doing something useful.
 # first, we catch up with any existing containers that are already deployed.
-for container in client.containers.list():
-    container_add(container.name)
+for container in client.containers():
+    container_add(get_name(container))
 
 if args.ONCE_MODE:
     sys.exit(0)
 
 # calling events will basically poll forever, so after this we're
 #  essentially in not-quite-a-daemon mode
-for event_json in client.events():
-    print "SAW: %s" % str(event_json)
-    event = json.loads(str(event_json))
-
-    if event.get("status") == "start":
-        event_add(event)
-    elif event.get("status") == "kill":
-        event_remove(event)
+try:
+    for event_json in client.events():
+        print "SAW: %s" % str(event_json)
+        event = json.loads(str(event_json))
+
+        if event.get("status") == "start":
+            event_add(event)
+        elif event.get("status") in ["kill","destroy","die"]:
+            event_remove(event)
+except KeyboardInterrupt as ki:
+    print "Exiting."