devserver: Better accounting of limited update responses.
This is a revision of the dedupe mechanism used for limiting the number
of updates that a client can get from a devserver (a feature that was
originally added to compensate for the lack of a true rule-based
handling of update requests). The way it is currently implemented
sometimes results in a situation where a client receives a "no update"
response instead of the expected "update available" response.
With this change, the devserver only decrements the allowed updates
counter when it receives an event notification from the client that the
download of an update has actually started. Unlike the update request,
whose handling may time out and lead to retransmits, this event is
a unique indication that a client has actually consumed the update. As
before, this accounting is done within a critical section, to prevent
race conditions.
This also takes care of another TODO item: when the devserver receives
a non-update ping, it will correctly return an ack (instead of a "no
update" response, as it currently does).
Finally, this prepends an underscore to internal constant names in
autoupdate_lib.
BUG=chromium:348097
TEST=None
Change-Id: I3cf5a7554e6cbc08df4df4cdadb2706c1747f9ba
Reviewed-on: https://chromium-review.googlesource.com/196314
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/autoupdate_lib.py b/autoupdate_lib.py
index a61d5e5..2e7a08b 100644
--- a/autoupdate_lib.py
+++ b/autoupdate_lib.py
@@ -10,11 +10,29 @@
from xml.dom import minidom
-APP_ID = '87efface-864d-49a5-9bb3-4b050a7c227a'
+# Update events and result codes.
+EVENT_TYPE_UNKNOWN = 0
+EVENT_TYPE_DOWNLOAD_COMPLETE = 1
+EVENT_TYPE_INSTALL_COMPLETE = 2
+EVENT_TYPE_UPDATE_COMPLETE = 3
+EVENT_TYPE_UPDATE_DOWNLOAD_STARTED = 13
+EVENT_TYPE_UPDATE_DOWNLOAD_FINISHED = 14
+
+EVENT_RESULT_ERROR = 0
+EVENT_RESULT_SUCCESS = 1
+EVENT_RESULT_SUCCESS_REBOOT = 2
+EVENT_RESULT_UPDATE_DEFERRED = 9
+
+
+# A default app_id value.
+_APP_ID = '87efface-864d-49a5-9bb3-4b050a7c227a'
+
# Responses for the various Omaha protocols indexed by the protocol version.
-UPDATE_RESPONSE = {}
-UPDATE_RESPONSE['2.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+#
+# Update available responses:
+_UPDATE_RESPONSE = {}
+_UPDATE_RESPONSE['2.0'] = """<?xml version="1.0" encoding="UTF-8"?>
<gupdate xmlns="http://www.google.com/update2/response" protocol="2.0">
<daystart elapsed_seconds="%(time_elapsed)s"/>
<app appid="{%(appid)s}" status="ok">
@@ -30,11 +48,8 @@
status="ok"
%(extra_attr)s/>
</app>
- </gupdate>
- """
-
-
-UPDATE_RESPONSE['3.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+ </gupdate>"""
+_UPDATE_RESPONSE['3.0'] = """<?xml version="1.0" encoding="UTF-8"?>
<response protocol="3.0">
<daystart elapsed_seconds="%(time_elapsed)s"/>
<app appid="{%(appid)s}" status="ok">
@@ -59,33 +74,46 @@
</manifest>
</updatecheck>
</app>
- </response>
- """
+ </response>"""
-
-# Responses for the various Omaha protocols indexed by the protocol version
-# when there's no update to be served.
-NO_UPDATE_RESPONSE = {}
-NO_UPDATE_RESPONSE['2.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+# No update responses:
+_NO_UPDATE_RESPONSE = {}
+_NO_UPDATE_RESPONSE['2.0'] = """<?xml version="1.0" encoding="UTF-8"?>
<gupdate xmlns="http://www.google.com/update2/response" protocol="2.0">
<daystart elapsed_seconds="%(time_elapsed)s"/>
<app appid="{%(appid)s}" status="ok">
<ping status="ok"/>
<updatecheck status="noupdate"/>
</app>
- </gupdate>
- """
-
-
-NO_UPDATE_RESPONSE['3.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+ </gupdate>"""
+_NO_UPDATE_RESPONSE['3.0'] = """<?xml version="1.0" encoding="UTF-8"?>
<response protocol="3.0">
<daystart elapsed_seconds="%(time_elapsed)s"/>
<app appid="{%(appid)s}" status="ok">
<ping status="ok"/>
<updatecheck status="noupdate"/>
</app>
- </response>
- """
+ </response>"""
+
+
+# Non-update event responses:
+_EVENT_RESPONSE = {}
+_EVENT_RESPONSE['2.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+ <gupdate xmlns="http://www.google.com/update2/response" protocol="2.0">
+ <daystart elapsed_seconds="%(time_elapsed)s"/>
+ <app appid="{%(appid)s}" status="ok">
+ <ping status="ok"/>
+ <event status="ok"/>
+ </app>
+ </gupdate>"""
+_EVENT_RESPONSE['3.0'] = """<?xml version="1.0" encoding="UTF-8"?>
+ <response protocol="3.0">
+ <daystart elapsed_seconds="%(time_elapsed)s"/>
+ <app appid="{%(appid)s}" status="ok">
+ <ping status="ok"/>
+ <event status="ok"/>
+ </app>
+ </response>"""
class UnknownProtocolRequestedException(Exception):
@@ -101,7 +129,7 @@
def GetCommonResponseValues():
"""Returns a dictionary of default values for the response."""
response_values = {}
- response_values['appid'] = APP_ID
+ response_values['appid'] = _APP_ID
response_values['time_elapsed'] = GetSecondsSinceMidnight()
return response_values
@@ -113,6 +141,7 @@
response_dict: Canned response messages indexed by protocol.
protocol: client's protocol version from the request Xml.
response_values: Values to be substituted in the canned response.
+
Returns:
Xml string to be passed back to client.
"""
@@ -136,6 +165,7 @@
public_key: the public key to transmit to the client or None if no key.
protocol: client's protocol version from the request Xml.
critical_update: whether this is a critical update.
+
Returns:
Xml string to be passed back to client.
"""
@@ -164,7 +194,7 @@
extra_attributes.append('PublicKeyRsa="%s"' % public_key)
response_values['extra_attr'] = ' '.join(extra_attributes)
- return GetSubstitutedResponse(UPDATE_RESPONSE, protocol, response_values)
+ return GetSubstitutedResponse(_UPDATE_RESPONSE, protocol, response_values)
def GetNoUpdateResponse(protocol):
@@ -172,21 +202,37 @@
Args:
protocol: client's protocol version from the request Xml.
+
Returns:
Xml string to be passed back to client.
"""
response_values = GetCommonResponseValues()
- return GetSubstitutedResponse(NO_UPDATE_RESPONSE, protocol, response_values)
+ return GetSubstitutedResponse(_NO_UPDATE_RESPONSE, protocol, response_values)
+
+
+def GetEventResponse(protocol):
+ """Returns a protocol-specific response to a client event notification.
+
+ Args:
+ protocol: client's protocol version from the request Xml.
+
+ Returns:
+ Xml string to be passed back to client.
+ """
+ response_values = GetCommonResponseValues()
+ return GetSubstitutedResponse(_EVENT_RESPONSE, protocol, response_values)
def ParseUpdateRequest(request_string):
"""Returns a tuple containing information parsed from an update request.
Args:
- request_dom: an xml string containing the update request.
+ request_string: an xml string containing the update request.
+
Returns:
Tuple consisting of protocol string, app element, event element, and
update_check element.
+
Raises UnknownProtocolRequestedException if we do not understand the
protocol.
"""