Implement keep-alive flag

CHANGELOG

@@ -1,3 +1,5 @@
+- 0.2.1
+	* Implement --keep-alive flag
 - 0.2.0
 	* Dependency upgrades
 - 0.1.0

eth_monitor/runnable/sync.py

@@ -105,6 +105,7 @@ config.add(args.offset, '_SYNC_OFFSET', True)
 config.add(args.skip_history, '_NO_HISTORY', True)
 config.add(args.single, '_SINGLE', True)
 config.add(args.head, '_HEAD', True)
+config.add(args.keep_alive, '_KEEP_ALIVE', True)
 override(config, 'renderer', env=os.environ, args=args)
 override(config, 'filter', env=os.environ, args=args)
 logg.debug('loaded config:\n{}'.format(config))
@@ -237,7 +238,7 @@ def setup_cache_filter(rules_filter=None):
     return CacheFilter(rules_filter=rules_filter)
 
 
-def setup_backend_resume(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False):
+def setup_backend_resume(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False, keep_alive=False):
     syncers = []
     syncer_backends = FileBackend.resume(chain_spec, block_offset, base_dir=state_dir)
     if len(syncer_backends) == 0:
@@ -258,42 +259,55 @@ def setup_backend_resume(chain_spec, block_offset, block_limit, state_dir, callb
         syncers.append(HistorySyncer(syncer_backend, chain_interface, block_callback=callback)) #RuledFilter.block_callback))
 
     syncer_backend = FileBackend.live(chain_spec, block_offset+1, base_dir=state_dir)
-    syncers.append(HeadSyncer(syncer_backend, chain_interface, block_callback=callback))
+
+    if len(syncers) == 0 or keep_alive:
+        head_syncer_backend = FileBackend.live(chain_spec, block_offset, base_dir=state_dir)
+        syncers.append(HeadSyncer(head_syncer_backend, chain_interface, block_callback=callback))
+
     return syncers  
 
 
-def setup_backend_single(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False):
-    logg.debug('block limit {}'.format(block_limit))
+def setup_backend_single(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False, keep_alive=False):
+    logg.info('block limit {} offset {} syncoffset {}'.format(block_limit, block_offset, sync_offset))
     syncer_backend = FileBackend.initial(chain_spec, block_limit, start_block_height=sync_offset, base_dir=state_dir)
+    syncers = []
     syncer = HistorySyncer(syncer_backend, chain_interface, block_callback=callback)
-    return [syncer]
+    syncers.append(syncer)
+    if keep_alive:
+        logg.info('i have keep alive')
+        head_syncer_backend = FileBackend.live(chain_spec, block_offset, base_dir=state_dir)
+        syncers.append(HeadSyncer(head_syncer_backend, chain_interface, block_callback=callback))
+    return syncers
 
 
-def setup_backend_head(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False):
+def setup_backend_head(chain_spec, block_offset, block_limit, state_dir, callback, chain_interface, sync_offset=0, skip_history=False, keep_alive=True):
     syncer_backend = FileBackend.live(chain_spec, block_offset, base_dir=state_dir)
     syncer = HeadSyncer(syncer_backend, chain_interface, block_callback=callback)
     return [syncer]
 
 
 def main():
+    keep_alive = False
     session_block_offset = 0
     if args.head:
         session_block_offset = -1
+        keep_alive = True
     else:
         session_block_offset = args.offset
 
+    o = block_latest()
+    r = rpc.do(o)
+    block_offset = int(strip_0x(r), 16) + 1
+    logg.info('network block height is {}'.format(block_offset))
+
     block_limit = 0
     if args.until > 0:
         if not args.head and args.until <= block_offset:
             raise ValueError('sync termination block number must be later than offset ({} >= {})'.format(block_offset, args.until))
         block_limit = args.until
-
-
-
-    o = block_latest()
-    r = rpc.do(o)
-    block_offset = int(strip_0x(r), 16) + 1
-    logg.info('network block height is {}'.format(block_offset))
+    elif config.true('_KEEP_ALIVE'):
+        keep_alive=True
+        block_limit = block_offset
 
     if session_block_offset == -1:
         session_block_offset = block_offset
@@ -357,6 +371,7 @@ def main():
                 chain_interface,
                 sync_offset=config.get('_SYNC_OFFSET'),
                 skip_history=config.true('_NO_HISTORY'),
+                keep_alive=keep_alive,
                 )
 
     out_filter = OutFilter(chain_spec, rules_filter=address_rules, renderers=renderers_mods)

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = eth-monitor
-version = 0.2.0
+version = 0.2.1
 description = Monitor and cache transactions using match filters
 author = Louis Holbrook
 author_email = dev@holbrook.no