Allow optional dependencies between components

src/tribler-core/tribler_core/components/base.py

@@ -94,12 +94,6 @@ async def start(self, failfast=True):
     async def shutdown(self):
         await gather(*[create_task(component.stop()) for component in self.components.values()])
 
-    def get(self, interface: Type[T]) -> T:
-        imp = self.components.get(interface)
-        if imp is None:
-            raise ComponentError(f"{interface.__name__} implementation not found in {self}")
-        return imp
-
     def __enter__(self):
         Session._stack.append(self)
 
@@ -140,19 +134,28 @@ def make_implementation(cls: Type[T], config, enable) -> T:
         assert False, f"Abstract classmethod make_implementation not implemented in class {cls.__name__}"
 
     @classmethod
-    def _find_implementation(cls: Type[T]) -> T:
+    def _find_implementation(cls: Type[T], required=True) -> T:
         session = Session.current()
-        return session.get(cls)
+        imp = session.components.get(cls)
+        if imp is None:
+            if required:
+                raise ComponentError(f"{cls.__name__} implementation not found in {session}")
+            imp = cls.make_implementation(session.config, enable=False)  # dummy implementation
+            session.register(cls, imp)
+            imp.started.set()
+        return imp
 
     @classmethod
-    def imp(cls: Type[T]) -> T:
-        return cls._find_implementation()
+    def imp(cls: Type[T], required=True) -> T:
+        return cls._find_implementation(required=required)
 
     async def start(self):
         try:
             await self.run()
         except Exception as e:
-            print(f'\n*** Exception in {self.__class__.__name__}.start(): {type(e).__name__}:{e}\n')
+            # Writing to stderr is for the case when logger is not configured properly (as my happen in local tests,
+            # for example) to avoid silent suppression of the important exceptions
+            sys.stderr.write(f'\nException in {self.__class__.__name__}.start(): {type(e).__name__}:{e}\n')
             self.logger.exception(f'Exception in {self.__class__.__name__}.start(): {type(e).__name__}:{e}')
             self.failed = True
             self.started.set()
@@ -175,8 +178,8 @@ async def run(self):
     async def shutdown(self):
         pass
 
-    async def use(self, dependency: Type[T]) -> T:
-        dep = dependency.imp()
+    async def use(self, dependency: Type[T], required=True) -> T:
+        dep = dependency.imp(required=required)
         await dep.started.wait()
         if dep.failed:
             raise ComponentError(f'Component {self.__class__.__name__} has failed dependency {dep.__class__.__name__}')

src/tribler-core/tribler_core/components/implementation/bandwidth_accounting.py

@@ -18,8 +18,8 @@ class BandwidthAccountingComponentImp(BandwidthAccountingComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
-        await self.use(UpgradeComponent)
+        await self.use(ReporterComponent, required=False)
+        await self.use(UpgradeComponent, required=False)
         config = self.session.config
 
         ipv8_component = await self.use(Ipv8Component)

src/tribler-core/tribler_core/components/implementation/gigachannel.py

@@ -19,7 +19,7 @@ class GigaChannelComponentImp(GigaChannelComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
         notifier = self.session.notifier

src/tribler-core/tribler_core/components/implementation/gigachannel_manager.py

@@ -11,7 +11,7 @@ class GigachannelManagerComponentImp(GigachannelManagerComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
         notifier = self.session.notifier

src/tribler-core/tribler_core/components/implementation/ipv8.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 from ipv8.bootstrapping.dispersy.bootstrapper import DispersyBootstrapper
 from ipv8.configuration import ConfigBuilder, DISPERSY_BOOTSTRAPPER
 from ipv8.dht.churn import PingChurn
@@ -24,15 +26,16 @@
 
 class Ipv8ComponentImp(Ipv8Component):
     task_manager: TaskManager
-    rest_manager: RESTManager
+    rest_manager: Optional[RESTManager]
 
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
 
-        rest_component = await self.use(RESTComponent)
-        rest_manager = self.rest_manager = rest_component.rest_manager
+        rest_component = await self.use(RESTComponent, required=False)
+        rest_manager = self.rest_manager = rest_component.rest_manager if rest_component.enabled else None
+
         self.task_manager = TaskManager()
 
         port = config.ipv8.port
@@ -76,7 +79,8 @@ async def run(self):
                         config.ipv8.walk_interval,
                         config.ipv8.walk_scaling_upper_limit).start(self.task_manager)
 
-        rest_manager.get_endpoint('statistics').ipv8 = ipv8
+        if rest_manager:
+            rest_manager.get_endpoint('statistics').ipv8 = ipv8
 
         self.peer_discovery_community = self.dht_discovery_community = None
 
@@ -93,9 +97,10 @@ async def run(self):
         endpoints_to_init = ['/asyncio', '/attestation', '/dht', '/identity',
                              '/isolation', '/network', '/noblockdht', '/overlays']
 
-        for path, endpoint in rest_manager.get_endpoint('ipv8').endpoints.items():
-            if path in endpoints_to_init:
-                endpoint.initialize(ipv8)
+        if rest_manager:
+            for path, endpoint in rest_manager.get_endpoint('ipv8').endpoints.items():
+                if path in endpoints_to_init:
+                    endpoint.initialize(ipv8)
 
     def make_bootstrapper(self) -> DispersyBootstrapper:
         args = DISPERSY_BOOTSTRAPPER['init']
@@ -124,7 +129,8 @@ def init_dht_discovery_community(self):
         self.dht_discovery_community = community
 
     async def shutdown(self):
-        self.rest_manager.get_endpoint('statistics').ipv8 = None
+        if self.rest_manager:
+            self.rest_manager.get_endpoint('statistics').ipv8 = None
         await self.release(RESTComponent)
 
         await self.unused.wait()

src/tribler-core/tribler_core/components/implementation/libtorrent.py

@@ -15,8 +15,8 @@ class LibtorrentComponentImp(LibtorrentComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
-        await self.use(UpgradeComponent)
+        await self.use(ReporterComponent, required=False)
+        await self.use(UpgradeComponent, required=False)
         socks_ports = (await self.use(SocksServersComponent)).socks_ports
         masterkey = await self.use(MasterKeyComponent)
 

src/tribler-core/tribler_core/components/implementation/metadata_store.py

@@ -14,8 +14,8 @@ class MetadataStoreComponentImp(MetadataStoreComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
-        await self.use(UpgradeComponent)
+        await self.use(ReporterComponent, required=False)
+        await self.use(UpgradeComponent, required=False)
         rest_manager = self.rest_manager = (await self.use(RESTComponent)).rest_manager
 
         config = self.session.config

src/tribler-core/tribler_core/components/implementation/payout.py

@@ -1,6 +1,3 @@
-from ipv8.dht.routing import RoutingTable
-from ipv8.messaging.interfaces.udp.endpoint import UDPv4Address
-
 from tribler_common.simpledefs import NTFY
 
 from tribler_core.components.interfaces.bandwidth_accounting import BandwidthAccountingComponent
@@ -14,7 +11,7 @@
 
 class PayoutComponentImp(PayoutComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
 

src/tribler-core/tribler_core/components/implementation/popularity.py

@@ -13,7 +13,7 @@
 
 class PopularityComponentImp(PopularityComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
         ipv8_component = await self.use(Ipv8Component)

src/tribler-core/tribler_core/components/implementation/resource_monitor.py

@@ -8,8 +8,8 @@
 
 class ResourceMonitorComponentImp(ResourceMonitorComponent):
     async def run(self):
-        await self.use(ReporterComponent)
-        await self.use(UpgradeComponent)
+        await self.use(ReporterComponent, required=False)
+        await self.use(UpgradeComponent, required=False)
         tunnel_community = (await self.use(TunnelsComponent)).community
 
         config = self.session.config

src/tribler-core/tribler_core/components/implementation/restapi.py

@@ -10,7 +10,7 @@
 class RESTComponentImp(RESTComponent):
 
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
         session = self.session
         config = session.config
         notifier = session.notifier

src/tribler-core/tribler_core/components/implementation/socks_configurator.py

@@ -7,7 +7,7 @@
 
 class SocksServersComponentImp(SocksServersComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
         self.socks_servers = []
         self.socks_ports = []
         # Start the SOCKS5 servers

src/tribler-core/tribler_core/components/implementation/torrent_checker.py

@@ -15,7 +15,7 @@ class TorrentCheckerComponentImp(TorrentCheckerComponent):
     rest_manager: RESTManager
 
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
 

src/tribler-core/tribler_core/components/implementation/tunnels.py

@@ -17,18 +17,25 @@
 
 class TunnelsComponentImp(TunnelsComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
 
         config = self.session.config
         ipv8_component = await self.use(Ipv8Component)
         ipv8 = ipv8_component.ipv8
         peer = ipv8_component.peer
         dht_discovery_community = ipv8_component.dht_discovery_community
 
-        bandwidth_community = (await self.use(BandwidthAccountingComponent)).community
-        download_manager = (await self.use(LibtorrentComponent)).download_manager
-        rest_manager = (await self.use(RESTComponent)).rest_manager
-        socks_servers = (await self.use(SocksServersComponent)).socks_servers
+        bandwidth_component = await self.use(BandwidthAccountingComponent, required=False)
+        bandwidth_community = bandwidth_component.community if bandwidth_component.enabled else None
+
+        download_component = await self.use(LibtorrentComponent, required=False)
+        download_manager = download_component.download_manager if download_component.enabled else None
+
+        rest_component = await self.use(RESTComponent, required=False)
+        rest_manager = rest_component.rest_manager if rest_component.enabled else None
+
+        socks_servers_component = await self.use(SocksServersComponent, required=False)
+        socks_servers = socks_servers_component.socks_servers if socks_servers_component.enabled else None
 
         settings = TunnelSettings()
         settings.min_circuits = config.tunnel_community.min_circuits
@@ -56,8 +63,10 @@ async def run(self):
 
         self.community = community
 
-        rest_manager.get_endpoint('downloads').tunnel_community = community
-        rest_manager.get_endpoint('ipv8').endpoints['/tunnel'].initialize(ipv8)
+        if rest_component.enabled:
+            rest_manager.get_endpoint('ipv8').endpoints['/tunnel'].initialize(ipv8)
+            if download_component.enabled:
+                rest_manager.get_endpoint('downloads').tunnel_community = community
 
     async def shutdown(self):
         await self.community.unload()

src/tribler-core/tribler_core/components/implementation/upgrade.py

@@ -9,7 +9,7 @@
 
 class UpgradeComponentImp(UpgradeComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
         config = self.session.config
         notifier = self.session.notifier
         masterkey = await self.use(MasterKeyComponent)

src/tribler-core/tribler_core/components/implementation/version_check.py

@@ -6,8 +6,8 @@
 
 class VersionCheckComponentImp(VersionCheckComponent):
     async def run(self):
-        await self.use(ReporterComponent)
-        await self.use(UpgradeComponent)
+        await self.use(ReporterComponent, required=False)
+        await self.use(UpgradeComponent, required=False)
 
         notifier = self.session.notifier
 

src/tribler-core/tribler_core/components/implementation/watch_folder.py

@@ -9,7 +9,7 @@
 
 class WatchFolderComponentImp(WatchFolderComponent):
     async def run(self):
-        await self.use(ReporterComponent)
+        await self.use(ReporterComponent, required=False)
         config = self.session.config
         notifier = self.session.notifier
         download_manager = (await self.use(LibtorrentComponent)).download_manager