bitbake: server: Rework the server API so process and xmlrpc servers coexist

This changes the way bitbake server works quite radically. Now, the
server is always a process based server with the option of starting
an XMLRPC listener on a specific inferface/port.

Behind the scenes this is done with a "bitbake.sock" file alongside
the bitbake.lock file. If we can obtain the lock, we know we need
to start a server. The server always listens on the socket and UIs
can then connect to this. UIs connect by sending a set of three file
descriptors over the domain socket, one for sending commands, one for
receiving command results and the other for receiving events.

These changes meant we can throw away all the horrid server abstraction
code, the plugable transport option to bitbake and the code becomes
much more readable and debuggable. It also likely removes a ton of
ways you could hang the UI/cooker in weird ways due to all the race
conditions that existed with previous processes.

Changes:

 * The foreground option for bitbake-server was dropped. Just tail
   the log if you really want this, the codepaths were complicated enough
   without adding one for this.
 * BBSERVER="autodetect" was dropped. The server will autostart and
   autoconnect in process mode. You have to specify an xmlrpc server
   address since that can't be autodetected. I can't see a use case
   for autodetect now.
 * The transport/servetype option to bitbake was dropped.
 * A BB_SERVER_TIMEOUT variable is added which allows the server
   to stay resident for a period of time after the last client
   disconnects before unloading. This is used if the -T/--idle-timeout
   option is not passed to bitbake.

This change is invasive and may well introduce new issues however I
believe the codebase is in a much better position for further
development and debugging.

(Bitbake rev: 72a3dbe13a23588e24c0baca6d58c35cdeba3f63)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 154 insertions, 0 deletions

diff --git a/bitbake/lib/bb/server/xmlrpcclient.py b/bitbake/lib/bb/server/xmlrpcclient.py
new file mode 100644
index 0000000000..4661a9e5a0
--- /dev/null
+++ b/bitbake/lib/bb/server/xmlrpcclient.py
@@ -0,0 +1,154 @@
+#
+# BitBake XMLRPC Client Interface
+#
+# Copyright (C) 2006 - 2007  Michael 'Mickey' Lauer
+# Copyright (C) 2006 - 2008  Richard Purdie
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import os
+import sys
+
+import socket
+import http.client
+import xmlrpc.client
+
+import bb
+from bb.ui import uievent
+
+class BBTransport(xmlrpc.client.Transport):
+    def __init__(self, timeout):
+        self.timeout = timeout
+        self.connection_token = None
+        xmlrpc.client.Transport.__init__(self)
+
+    # Modified from default to pass timeout to HTTPConnection
+    def make_connection(self, host):
+        #return an existing connection if possible.  This allows
+        #HTTP/1.1 keep-alive.
+        if self._connection and host == self._connection[0]:
+            return self._connection[1]
+
+        # create a HTTP connection object from a host descriptor
+        chost, self._extra_headers, x509 = self.get_host_info(host)
+        #store the host argument along with the connection object
+        self._connection = host, http.client.HTTPConnection(chost, timeout=self.timeout)
+        return self._connection[1]
+
+    def set_connection_token(self, token):
+        self.connection_token = token
+
+    def send_content(self, h, body):
+        if self.connection_token:
+            h.putheader("Bitbake-token", self.connection_token)
+        xmlrpc.client.Transport.send_content(self, h, body)
+
+def _create_server(host, port, timeout = 60):
+    t = BBTransport(timeout)
+    s = xmlrpc.client.ServerProxy("http://%s:%d/" % (host, port), transport=t, allow_none=True, use_builtin_types=True)
+    return s, t
+
+def check_connection(remote, timeout):
+    try:
+        host, port = remote.split(":")
+        port = int(port)
+    except Exception as e:
+        bb.warn("Failed to read remote definition (%s)" % str(e))
+        raise e
+
+    server, _transport = _create_server(host, port, timeout)
+    try:
+        ret, err =  server.runCommand(['getVariable', 'TOPDIR'])
+        if err or not ret:
+            return False
+    except ConnectionError:
+        return False
+    return True
+
+class BitBakeXMLRPCServerConnection(object):
+    def __init__(self, host, port, clientinfo=("localhost", 0), observer_only = False, featureset = None):
+        self.connection, self.transport = _create_server(host, port)
+        self.clientinfo = clientinfo
+        self.observer_only = observer_only
+        if featureset:
+            self.featureset = featureset
+        else:
+            self.featureset = []
+
+        self.events = uievent.BBUIEventQueue(self.connection, self.clientinfo)
+
+        _, error = self.connection.runCommand(["setFeatures", self.featureset])
+        if error:
+            # disconnect the client, we can't make the setFeature work
+            self.connection.removeClient()
+            # no need to log it here, the error shall be sent to the client
+            raise BaseException(error)
+
+    def connect(self, token = None):
+        if token is None:
+            if self.observer_only:
+                token = "observer"
+            else:
+                token = self.connection.addClient()
+
+        if token is None:
+            return None
+
+        self.transport.set_connection_token(token)
+        return self
+
+    def removeClient(self):
+        if not self.observer_only:
+            self.connection.removeClient()
+
+    def terminate(self):
+        # Don't wait for server indefinitely
+        socket.setdefaulttimeout(2)
+        try:
+            self.events.system_quit()
+        except:
+            pass
+        try:
+            self.connection.removeClient()
+        except:
+            pass
+
+def connectXMLRPC(remote, featureset, observer_only = False, token = None):
+    # The format of "remote" must be "server:port"
+    try:
+        [host, port] = remote.split(":")
+        port = int(port)
+    except Exception as e:
+        bb.warn("Failed to parse remote definition %s (%s)" % (remote, str(e)))
+        raise e
+
+    # We need our IP for the server connection. We get the IP
+    # by trying to connect with the server
+    try:
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.connect((host, port))
+        ip = s.getsockname()[0]
+        s.close()
+    except Exception as e:
+        bb.warn("Could not create socket for %s:%s (%s)" % (host, port, str(e)))
+        raise e
+    try:
+        connection = BitBakeXMLRPCServerConnection(host, port, (ip, 0), observer_only, featureset)
+        return connection.connect(token)
+    except Exception as e:
+        bb.warn("Could not connect to server at %s:%s (%s)" % (host, port, str(e)))
+        raise e
+
+
+