Add basic functionality

Signed-off-by: Angus Salkeld <asalkeld@redhat.com>

1 files changed, 276 insertions, 0 deletions

diff --git a/ceilometerclient/common/http.py b/ceilometerclient/common/http.py
new file mode 100644
index 0000000..2c61536
--- /dev/null
+++ b/ceilometerclient/common/http.py
@@ -0,0 +1,276 @@
+# Copyright 2012 OpenStack LLC.
+# All Rights Reserved.
+#
+#    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 copy
+import httplib
+import logging
+import os
+import socket
+import StringIO
+import urlparse
+
+try:
+    import ssl
+except ImportError:
+    #TODO(bcwaldon): Handle this failure more gracefully
+    pass
+
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
+# Python 2.5 compat fix
+if not hasattr(urlparse, 'parse_qsl'):
+    import cgi
+    urlparse.parse_qsl = cgi.parse_qsl
+
+
+from ceilometerclient import exc
+
+
+LOG = logging.getLogger(__name__)
+USER_AGENT = 'python-ceilometerclient'
+CHUNKSIZE = 1024 * 64  # 64kB
+
+
+class HTTPClient(object):
+
+    def __init__(self, endpoint, **kwargs):
+        self.endpoint = endpoint
+        self.auth_token = kwargs.get('token')
+        self.connection_params = self.get_connection_params(endpoint, **kwargs)
+
+    @staticmethod
+    def get_connection_params(endpoint, **kwargs):
+        parts = urlparse.urlparse(endpoint)
+
+        _args = (parts.hostname, parts.port, parts.path)
+        _kwargs = {'timeout': float(kwargs.get('timeout', 600))}
+
+        if parts.scheme == 'https':
+            _class = VerifiedHTTPSConnection
+            _kwargs['ca_file'] = kwargs.get('ca_file', None)
+            _kwargs['cert_file'] = kwargs.get('cert_file', None)
+            _kwargs['key_file'] = kwargs.get('key_file', None)
+            _kwargs['insecure'] = kwargs.get('insecure', False)
+        elif parts.scheme == 'http':
+            _class = httplib.HTTPConnection
+        else:
+            msg = 'Unsupported scheme: %s' % parts.scheme
+            raise exc.InvalidEndpoint(msg)
+
+        return (_class, _args, _kwargs)
+
+    def get_connection(self):
+        _class = self.connection_params[0]
+        try:
+            return _class(*self.connection_params[1],
+                          **self.connection_params[2])
+        except httplib.InvalidURL:
+            raise exc.InvalidEndpoint()
+
+    def log_curl_request(self, method, url, kwargs):
+        curl = ['curl -i -X %s' % method]
+
+        for (key, value) in kwargs['headers'].items():
+            header = '-H \'%s: %s\'' % (key, value)
+            curl.append(header)
+
+        conn_params_fmt = [
+            ('key_file', '--key %s'),
+            ('cert_file', '--cert %s'),
+            ('ca_file', '--cacert %s'),
+        ]
+        for (key, fmt) in conn_params_fmt:
+            value = self.connection_params[2].get(key)
+            if value:
+                curl.append(fmt % value)
+
+        if self.connection_params[2].get('insecure'):
+            curl.append('-k')
+
+        if 'body' in kwargs:
+            curl.append('-d \'%s\'' % kwargs['body'])
+
+        curl.append('%s%s' % (self.endpoint, url))
+        LOG.debug(' '.join(curl))
+
+    @staticmethod
+    def log_http_response(resp, body=None):
+        status = (resp.version / 10.0, resp.status, resp.reason)
+        dump = ['\nHTTP/%.1f %s %s' % status]
+        dump.extend(['%s: %s' % (k, v) for k, v in resp.getheaders()])
+        dump.append('')
+        if body:
+            dump.extend([body, ''])
+        LOG.debug('\n'.join(dump))
+
+    def _http_request(self, url, method, **kwargs):
+        """ Send an http request with the specified characteristics.
+
+        Wrapper around httplib.HTTP(S)Connection.request to handle tasks such
+        as setting headers and error handling.
+        """
+        # Copy the kwargs so we can reuse the original in case of redirects
+        kwargs['headers'] = copy.deepcopy(kwargs.get('headers', {}))
+        kwargs['headers'].setdefault('User-Agent', USER_AGENT)
+        if self.auth_token:
+            kwargs['headers'].setdefault('X-Auth-Token', self.auth_token)
+
+        self.log_curl_request(method, url, kwargs)
+        conn = self.get_connection()
+
+        try:
+            conn_params = self.connection_params[1][2]
+            conn_url = os.path.normpath('%s/%s' % (conn_params, url))
+            conn.request(method, conn_url, **kwargs)
+            resp = conn.getresponse()
+        except socket.gaierror as e:
+            message = "Error finding address for %(url)s: %(e)s" % locals()
+            raise exc.InvalidEndpoint(message=message)
+        except (socket.error, socket.timeout) as e:
+            endpoint = self.endpoint
+            message = "Error communicating with %(endpoint)s %(e)s" % locals()
+            raise exc.CommunicationError(message=message)
+
+        body_iter = ResponseBodyIterator(resp)
+
+        # Read body into string if it isn't obviously image data
+        if resp.getheader('content-type', None) != 'application/octet-stream':
+            body_str = ''.join([chunk for chunk in body_iter])
+            self.log_http_response(resp, body_str)
+            body_iter = StringIO.StringIO(body_str)
+        else:
+            self.log_http_response(resp)
+
+        if 400 <= resp.status < 600:
+            LOG.warn("Request returned failure status.")
+            raise exc.from_response(resp)
+        elif resp.status in (301, 302, 305):
+            # Redirected. Reissue the request to the new location.
+            return self._http_request(resp['location'], method, **kwargs)
+        elif resp.status == 300:
+            raise exc.from_response(resp)
+
+        return resp, body_iter
+
+    def json_request(self, method, url, **kwargs):
+        kwargs.setdefault('headers', {})
+        kwargs['headers'].setdefault('Content-Type', 'application/json')
+        kwargs['headers'].setdefault('Accept', 'application/json')
+
+        if 'body' in kwargs:
+            kwargs['body'] = json.dumps(kwargs['body'])
+
+        resp, body_iter = self._http_request(url, method, **kwargs)
+
+        if 'application/json' in resp.getheader('content-type', None):
+            body = ''.join([chunk for chunk in body_iter])
+            try:
+                body = json.loads(body)
+            except ValueError:
+                LOG.error('Could not decode response body as JSON')
+        else:
+            body = None
+
+        return resp, body
+
+    def raw_request(self, method, url, **kwargs):
+        kwargs.setdefault('headers', {})
+        kwargs['headers'].setdefault('Content-Type',
+                                     'application/octet-stream')
+        return self._http_request(url, method, **kwargs)
+
+
+class VerifiedHTTPSConnection(httplib.HTTPSConnection):
+    """httplib-compatibile connection using client-side SSL authentication
+
+    :see http://code.activestate.com/recipes/
+            577548-https-httplib-client-connection-with-certificate-v/
+    """
+
+    def __init__(self, host, port, key_file=None, cert_file=None,
+                 ca_file=None, timeout=None, insecure=False):
+        httplib.HTTPSConnection.__init__(self, host, port, key_file=key_file,
+                                         cert_file=cert_file)
+        self.key_file = key_file
+        self.cert_file = cert_file
+        if ca_file is not None:
+            self.ca_file = ca_file
+        else:
+            self.ca_file = self.get_system_ca_file()
+        self.timeout = timeout
+        self.insecure = insecure
+
+    def connect(self):
+        """
+        Connect to a host on a given (SSL) port.
+        If ca_file is pointing somewhere, use it to check Server Certificate.
+
+        Redefined/copied and extended from httplib.py:1105 (Python 2.6.x).
+        This is needed to pass cert_reqs=ssl.CERT_REQUIRED as parameter to
+        ssl.wrap_socket(), which forces SSL to check server certificate against
+        our client certificate.
+        """
+        sock = socket.create_connection((self.host, self.port), self.timeout)
+
+        if self._tunnel_host:
+            self.sock = sock
+            self._tunnel()
+
+        if self.insecure is True:
+            kwargs = {'cert_reqs': ssl.CERT_NONE}
+        else:
+            kwargs = {'cert_reqs': ssl.CERT_REQUIRED, 'ca_certs': self.ca_file}
+
+        if self.cert_file:
+            kwargs['certfile'] = self.cert_file
+            if self.key_file:
+                kwargs['keyfile'] = self.key_file
+
+        self.sock = ssl.wrap_socket(sock, **kwargs)
+
+    @staticmethod
+    def get_system_ca_file():
+        """"Return path to system default CA file"""
+        # Standard CA file locations for Debian/Ubuntu, RedHat/Fedora,
+        # Suse, FreeBSD/OpenBSD
+        ca_path = ['/etc/ssl/certs/ca-certificates.crt',
+                   '/etc/pki/tls/certs/ca-bundle.crt',
+                   '/etc/ssl/ca-bundle.pem',
+                   '/etc/ssl/cert.pem']
+        for ca in ca_path:
+            if os.path.exists(ca):
+                return ca
+        return None
+
+
+class ResponseBodyIterator(object):
+    """A class that acts as an iterator over an HTTP response."""
+
+    def __init__(self, resp):
+        self.resp = resp
+
+    def __iter__(self):
+        while True:
+            yield self.next()
+
+    def next(self):
+        chunk = self.resp.read(CHUNKSIZE)
+        if chunk:
+            return chunk
+        else:
+            raise StopIteration()