Docker support

checks.d/docker.py

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+import urllib2
+import urllib
+import httplib
+import socket
+import os
+from urlparse import urlsplit, urljoin
+from util import json, headers
+from checks import AgentCheck
+
+
+LXC_METRICS = [
+    {
+        "cgroup": "memory",
+        "file": "lxc/{0}/memory.stat",
+        "metrics": {
+            "active_anon": ("docker.mem.active_anon", "gauge"),
+            "active_file": ("docker.mem.active_file", "gauge"),
+            "cache": ("docker.mem.cache", "gauge"),
+            "hierarchical_memory_limit": ("docker.mem.hierarchical_memory_limit", "gauge"),
+            "hierarchical_memsw_limit": ("docker.mem.hierarchical_memsw_limit", "gauge"),
+            "inactive_anon": ("docker.mem.inactive_anon", "gauge"),
+            "inactive_file": ("docker.mem.inactive_file", "gauge"),
+            "mapped_file": ("docker.mem.mapped_file", "gauge"),
+            "pgfault": ("docker.mem.pgfault", "gauge"),
+            "pgmajfault": ("docker.mem.pgmajfault", "gauge"),
+            "pgpgin": ("docker.mem.pgpgin", "gauge"),
+            "pgpgout": ("docker.mem.pgpgout", "gauge"),
+            "rss": ("docker.mem.rss", "gauge"),
+            "swap": ("docker.mem.swap", "gauge"),
+            "unevictable": ("docker.mem.unevictable", "gauge"),
+            "total_active_anon": ("docker.mem.total_active_anon", "gauge"),
+            "total_active_file": ("docker.mem.total_active_file", "gauge"),
+            "total_cache": ("docker.mem.total_cache", "gauge"),
+            "total_inactive_anon": ("docker.mem.total_inactive_anon", "gauge"),
+            "total_inactive_file": ("docker.mem.total_inactive_file", "gauge"),
+            "total_mapped_file": ("docker.mem.total_mapped_file", "gauge"),
+            "total_pgfault": ("docker.mem.total_pgfault", "gauge"),
+            "total_pgmajfault": ("docker.mem.total_pgmajfault", "gauge"),
+            "total_pgpgin": ("docker.mem.total_pgpgin", "gauge"),
+            "total_pgpgout": ("docker.mem.total_pgpgout", "gauge"),
+            "total_rss": ("docker.mem.total_rss", "gauge"),
+            "total_swap": ("docker.mem.total_swap", "gauge"),
+            "total_unevictable": ("docker.mem.total_unevictable", "gauge"),
+        }
+    },
+    {
+        "cgroup": "cpuacct",
+        "file": "lxc/{0}/cpuacct.stat",
+        "metrics": {
+            "user": ("docker.cpu.user", "gauge"),
+            "system": ("docker.cpu.system", "gauge"),
+        },
+    },
+]
+
+DOCKER_METRICS = {
+    "SizeRw": ("docker.disk.size", "gauge"),
+}
+
+DOCKER_TAGS = [
+    "ID",
+    "Name",
+    "Created",
+    "Driver",
+    "Path",
+]
+
+DOCKER_CONFIG_TAGS = [
+    "Hostname",
+    "Image"
+]
+
+
+
+class UnixHTTPConnection(httplib.HTTPConnection, object):
+    """Class used in conjuction with UnixSocketHandler to make urllib2
+    compatible with Unix sockets."""
+    def __init__(self, unix_socket):
+        self._unix_socket = unix_socket
+
+    def connect(self):
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(self._unix_socket)
+        self.sock = sock
+
+    def __call__(self, *args, **kwargs):
+        httplib.HTTPConnection.__init__(self, *args, **kwargs)
+        return self
+
+
+class UnixSocketHandler(urllib2.AbstractHTTPHandler):
+    """Class that makes Unix sockets work with urllib2 without any additional
+    dependencies."""
+    def unix_open(self, req):
+        full_path = "%s%s" % urlsplit(req.get_full_url())[1:3]
+        path = os.path.sep
+        for part in full_path.split("/"):
+            path = os.path.join(path, part)
+            if not os.path.exists(path):
+                break
+            unix_socket = path
+        # add a host or else urllib2 complains
+        url = req.get_full_url().replace(unix_socket, "/localhost")
+        new_req = urllib2.Request(url, req.get_data(), dict(req.header_items()))
+        new_req.timeout = req.timeout
+        return self.do_open(UnixHTTPConnection(unix_socket), new_req)
+
+    unix_request = urllib2.AbstractHTTPHandler.do_request_
+
+
+class Docker(AgentCheck):
+    def __init__(self, *args, **kwargs):
+        super(Docker, self).__init__(*args, **kwargs)
+        urllib2.install_opener(urllib2.build_opener(UnixSocketHandler()))
+        self._mounpoints = {}
+        for metric in LXC_METRICS:
+            self._mounpoints[metric["cgroup"]] = self._find_cgroup(metric["cgroup"])
+
+    def check(self, instance):
+        tags = instance.get("tags") or []
+
+        for container in self._get_containers(instance):
+            container_details = self._get_container(instance, container["Id"])
+            container_tags = list(tags)
+            for key in DOCKER_TAGS:
+                container_tags.append("%s:%s" % (key.lower(), container_details[key]))
+            for key, (dd_key, metric_type) in DOCKER_METRICS.items():
+                if key in container:
+                    getattr(self, metric_type)(dd_key, int(container[key]), tags=container_tags)
+            for metric in LXC_METRICS:
+                mountpoint = self._mounpoints[metric["cgroup"]]
+                stat_file = os.path.join(mountpoint, metric["file"].format(container["Id"]))
+                stats = self._parse_cgroup_file(stat_file)
+                for key, (dd_key, metric_type) in metric["metrics"].items():
+                    if key in stats:
+                        getattr(self, metric_type)(dd_key, int(stats[key]), tags=container_tags)
+
+    def _get_containers(self, instance):
+        """Gets the list of running containers in Docker."""
+        return self._get_json("%(url)s/containers/json" % instance, params={"size": 1})
+
+    def _get_container(self, instance, cid):
+        """Get container information from Docker, gived a container Id."""
+        return self._get_json("%s/containers/%s/json" % (instance["url"], cid))
+
+    def _get_json(self, uri, params=None):
+        """Utility method to get and parse JSON streams."""
+        if params:
+            uri = "%s?%s" % (uri, urllib.urlencode(params))
+        req = urllib2.Request(uri, None)
+        request = urllib2.urlopen(req)
+        response = request.read()
+        return json.loads(response)
+
+    def _find_cgroup(self, hierarchy):
+        """Finds the mount point for a specified cgroup hierarchy. Works with
+        old style and new style mounts."""
+        try:
+            fp = open("/proc/mounts")
+            mounts = map(lambda x: x.split(), fp.read().splitlines())
+        finally:
+            fp.close()
+        cgroup_mounts = filter(lambda x: x[2] == "cgroup", mounts)
+        # Old cgroup style
+        if len(cgroup_mounts) == 1:
+            return cgroup_mounts[0][1]
+        for _, mountpoint, _, opts, _, _ in cgroup_mounts:
+            if hierarchy in opts:
+                return mountpoint
+
+    def _parse_cgroup_file(self, file_):
+        """Parses a cgroup pseudo file for key/values."""
+        try:
+            fp = open(file_)
+            return dict(map(lambda x: x.split(), fp.read().splitlines()))
+        finally:
+            fp.close()

conf.d/docker.yaml.example

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+init_config:
+
+instances:
+    - url: "unix://var/run/docker.sock"