hashserv: Chunkify large messages

The hash equivalence client and server can occasionally send messages
that are too large for the server to fit in the receive buffer (64 KB).
To prevent this, support is added to the protocol to "chunkify" the
stream and break it up into manageable pieces that the server can each
side can back together.

Ideally, this would be negotiated by the client and server, but it's
currently hard coded to 32 KB to prevent the round-trip delay.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit e27a28c1e40e886ee68ba4b99b537ffc9c3577d4)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 72 insertions, 33 deletions

diff --git a/lib/hashserv/server.py b/lib/hashserv/server.py
index cc7e48233..81050715e 100644
--- a/lib/hashserv/server.py
+++ b/lib/hashserv/server.py
@@ -13,6 +13,7 @@ import os
 import signal
 import socket
 import time
+from . import chunkify, DEFAULT_MAX_CHUNK
 
 logger = logging.getLogger('hashserv.server')
 
@@ -107,12 +108,29 @@ class Stats(object):
         return {k: getattr(self, k) for k in ('num', 'total_time', 'max_time', 'average', 'stdev')}
 
 
+class ClientError(Exception):
+    pass
+
 class ServerClient(object):
+    FAST_QUERY = 'SELECT taskhash, method, unihash FROM tasks_v2 WHERE method=:method AND taskhash=:taskhash ORDER BY created ASC LIMIT 1'
+    ALL_QUERY =  'SELECT *                         FROM tasks_v2 WHERE method=:method AND taskhash=:taskhash ORDER BY created ASC LIMIT 1'
+
     def __init__(self, reader, writer, db, request_stats):
         self.reader = reader
         self.writer = writer
         self.db = db
         self.request_stats = request_stats
+        self.max_chunk = DEFAULT_MAX_CHUNK
+
+        self.handlers = {
+            'get': self.handle_get,
+            'report': self.handle_report,
+            'report-equiv': self.handle_equivreport,
+            'get-stream': self.handle_get_stream,
+            'get-stats': self.handle_get_stats,
+            'reset-stats': self.handle_reset_stats,
+            'chunk-stream': self.handle_chunk,
+        }
 
     async def process_requests(self):
         try:
@@ -125,7 +143,11 @@ class ServerClient(object):
                 return
 
             (proto_name, proto_version) = protocol.decode('utf-8').rstrip().split()
-            if proto_name != 'OEHASHEQUIV' or proto_version != '1.0':
+            if proto_name != 'OEHASHEQUIV':
+                return
+
+            proto_version = tuple(int(v) for v in proto_version.split('.'))
+            if proto_version < (1, 0) or proto_version > (1, 1):
                 return
 
             # Read headers. Currently, no headers are implemented, so look for
@@ -140,40 +162,34 @@ class ServerClient(object):
                     break
 
             # Handle messages
-            handlers = {
-                'get': self.handle_get,
-                'report': self.handle_report,
-                'report-equiv': self.handle_equivreport,
-                'get-stream': self.handle_get_stream,
-                'get-stats': self.handle_get_stats,
-                'reset-stats': self.handle_reset_stats,
-            }
-
             while True:
                 d = await self.read_message()
                 if d is None:
                     break
-
-                for k in handlers.keys():
-                    if k in d:
-                        logger.debug('Handling %s' % k)
-                        if 'stream' in k:
-                            await handlers[k](d[k])
-                        else:
-                            with self.request_stats.start_sample() as self.request_sample, \
-                                    self.request_sample.measure():
-                                await handlers[k](d[k])
-                        break
-                else:
-                    logger.warning("Unrecognized command %r" % d)
-                    break
-
+                await self.dispatch_message(d)
                 await self.writer.drain()
+        except ClientError as e:
+            logger.error(str(e))
         finally:
             self.writer.close()
 
+    async def dispatch_message(self, msg):
+        for k in self.handlers.keys():
+            if k in msg:
+                logger.debug('Handling %s' % k)
+                if 'stream' in k:
+                    await self.handlers[k](msg[k])
+                else:
+                    with self.request_stats.start_sample() as self.request_sample, \
+                            self.request_sample.measure():
+                        await self.handlers[k](msg[k])
+                return
+
+        raise ClientError("Unrecognized command %r" % msg)
+
     def write_message(self, msg):
-        self.writer.write(('%s\n' % json.dumps(msg)).encode('utf-8'))
+        for c in chunkify(json.dumps(msg), self.max_chunk):
+            self.writer.write(c.encode('utf-8'))
 
     async def read_message(self):
         l = await self.reader.readline()
@@ -191,14 +207,38 @@ class ServerClient(object):
             logger.error('Bad message from client: %r' % message)
             raise e
 
+    async def handle_chunk(self, request):
+        lines = []
+        try:
+            while True:
+                l = await self.reader.readline()
+                l = l.rstrip(b"\n").decode("utf-8")
+                if not l:
+                    break
+                lines.append(l)
+
+            msg = json.loads(''.join(lines))
+        except (json.JSONDecodeError, UnicodeDecodeError) as e:
+            logger.error('Bad message from client: %r' % message)
+            raise e
+
+        if 'chunk-stream' in msg:
+            raise ClientError("Nested chunks are not allowed")
+
+        await self.dispatch_message(msg)
+
     async def handle_get(self, request):
         method = request['method']
         taskhash = request['taskhash']
 
-        row = self.query_equivalent(method, taskhash)
+        if request.get('all', False):
+            row = self.query_equivalent(method, taskhash, self.ALL_QUERY)
+        else:
+            row = self.query_equivalent(method, taskhash, self.FAST_QUERY)
+
         if row is not None:
             logger.debug('Found equivalent task %s -> %s', (row['taskhash'], row['unihash']))
-            d = {k: row[k] for k in ('taskhash', 'method', 'unihash')}
+            d = {k: row[k] for k in row.keys()}
 
             self.write_message(d)
         else:
@@ -228,7 +268,7 @@ class ServerClient(object):
 
                 (method, taskhash) = l.split()
                 #logger.debug('Looking up %s %s' % (method, taskhash))
-                row = self.query_equivalent(method, taskhash)
+                row = self.query_equivalent(method, taskhash, self.FAST_QUERY)
                 if row is not None:
                     msg = ('%s\n' % row['unihash']).encode('utf-8')
                     #logger.debug('Found equivalent task %s -> %s', (row['taskhash'], row['unihash']))
@@ -328,7 +368,7 @@ class ServerClient(object):
             # Fetch the unihash that will be reported for the taskhash. If the
             # unihash matches, it means this row was inserted (or the mapping
             # was already valid)
-            row = self.query_equivalent(data['method'], data['taskhash'])
+            row = self.query_equivalent(data['method'], data['taskhash'], self.FAST_QUERY)
 
             if row['unihash'] == data['unihash']:
                 logger.info('Adding taskhash equivalence for %s with unihash %s',
@@ -354,12 +394,11 @@ class ServerClient(object):
         self.request_stats.reset()
         self.write_message(d)
 
-    def query_equivalent(self, method, taskhash):
+    def query_equivalent(self, method, taskhash, query):
         # This is part of the inner loop and must be as fast as possible
         try:
             cursor = self.db.cursor()
-            cursor.execute('SELECT taskhash, method, unihash FROM tasks_v2 WHERE method=:method AND taskhash=:taskhash ORDER BY created ASC LIMIT 1',
-                           {'method': method, 'taskhash': taskhash})
+            cursor.execute(query, {'method': method, 'taskhash': taskhash})
             return cursor.fetchone()
         except:
             cursor.close()