Crate polkadot_overseer

Overseer

overseer implements the Overseer architecture described in the implementers’ guide. For the motivations behind implementing the overseer itself you should check out that guide, documentation in this crate will be mostly discussing technical stuff.

An Overseer is something that allows spawning/stopping and overseeing asynchronous tasks as well as establishing a well-defined and easy to use protocol that the tasks can use to communicate with each other. It is desired that this protocol is the only way tasks communicate with each other, however at this moment there are no foolproof guards against other ways of communication.

The Overseer is instantiated with a pre-defined set of Subsystems that share the same behavior from Overseer’s point of view.

                             +-----------------------------+
                             |         Overseer            |
                             +-----------------------------+

            ................|  Overseer "holds" these and uses |..............
            .                  them to (re)start things                      .
            .                                                                .
            .  +-------------------+                +---------------------+  .
            .  |   Subsystem1      |                |   Subsystem2        |  .
            .  +-------------------+                +---------------------+  .
            .           |                                       |            .
            ..................................................................
                        |                                       |
                      start()                                 start()
                        V                                       V
            ..................| Overseer "runs" these |.......................
            .  +--------------------+               +---------------------+  .
            .  | SubsystemInstance1 |               | SubsystemInstance2  |  .
            .  +--------------------+               +---------------------+  .
            ..................................................................

Re-exports

• pub use self::metrics::Metrics as OverseerMetrics;
• pub use self::dummy::DummySubsystem;
• pub use polkadot_node_metrics::metrics::prometheus;
• pub use orchestra as gen;

Modules

• dummy
  A dummy subsystem, mostly useful for placeholders and tests.
• messages
  The exclusive home of all generated dummy messages (if any at all)
• metrics
  Prometheus metrics related to the overseer and its channels.

Structs

• ActivatedLeaf
  Activated leaf.
• ActiveLeavesUpdate
  Changes in the set of active leaves: the parachain heads which we care to work on.
• BlockInfo
  An event telling the Overseer on the particular block that has been imported or finalized.
• ChannelsOut
  Collection of channels to the individual subsystems.
• Handle
  A handle used to communicate with the Overseer.
• HighPriority
  High priority.
• MessagePacket
  A wrapping type for messages.
• Metronome
  Create a stream of ticks with a defined cycle duration.
• Missing
  Type marker for the uninitialized field of the orchestra builder. PhantomData is used for type hinting when creating uninitialized builder, e.g. to avoid specifying the generics when instantiating the FooBuilder when calling Foo::builder()
• NormalPriority
  Normal priority.
• OrchestratedSubsystem
  A subsystem that the orchestrator orchestrates.
• Overseer
  The orchestra.
• OverseerBuilder
  Builder pattern to create compile time safe construction path.
• OverseerConnector
  External connector.
• OverseerSender
  Connector to send messages towards all subsystems, while tracking the which signals where already received.
• OverseerSubsystemContext
  A context type that is given to the Subsystem upon spawning. It can be used by Subsystem to communicate with other Subsystems or to spawn it’s SubsystemJobs.
• SignalsReceived
  Watermark to track the received signals.
• SpawnGlue
  Glue to connect trait orchestra::Spawner and SpawnNamed from substrate.
• SubsystemInstance
  A running instance of some Subsystem.
• SubsystemMeterReadouts
  Set of readouts of the Meters of a subsystem.
• SubsystemMeters
  Collection of meters related to a subsystem.

Enums

• AllMessages
  Generated message type wrapper over all possible messages used by any subsystem.
• ApprovalDistributionOutgoingMessages
• ApprovalVotingOutgoingMessages
• ApprovalVotingParallelOutgoingMessages
• AvailabilityDistributionOutgoingMessages
• AvailabilityRecoveryOutgoingMessages
• AvailabilityStoreOutgoingMessages
• BitfieldDistributionOutgoingMessages
• BitfieldSigningOutgoingMessages
• CandidateBackingOutgoingMessages
• CandidateValidationOutgoingMessages
• ChainApiOutgoingMessages
• ChainSelectionOutgoingMessages
• CollationGenerationOutgoingMessages
• CollatorProtocolOutgoingMessages
• DisputeCoordinatorOutgoingMessages
• DisputeDistributionOutgoingMessages
• Event
  An event from outside the overseer scope, such as the substrate framework or user interaction.
• ExternalRequest
  Some request from outer world.
• FromOrchestra
  A message type that a subsystem receives from an orchestra. It wraps signals from an orchestra and messages that are circulating between subsystems.
• GossipSupportOutgoingMessages
• Init
  Type for the initialized field of the orchestra builder
• NetworkBridgeRxOutgoingMessages
• NetworkBridgeTxOutgoingMessages
• OverseerError
  An error type that describes faults that may happen
• OverseerSignal
  Signals sent by an overseer to a subsystem.
• PriorityLevel
  Priority of messages sending to the individual subsystems. Only for the bounded channel sender.
• ProspectiveParachainsOutgoingMessages
• ProvisionerOutgoingMessages
• PvfCheckerOutgoingMessages
• RuntimeApiOutgoingMessages
• StatementDistributionOutgoingMessages
• SubsystemError
  An error type that describes faults that may happen
• ToOrchestra
  A type of messages that are sent from a Subsystem to the declared orchestra.
• TrySendError
  A bounded channel error when trying to send a message (transparently wraps the inner error type)

Traits

• ApprovalDistributionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ApprovalDistributionSenderTrait
  A abstracting trait for usage with subsystems.
• ApprovalVotingContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ApprovalVotingParallelContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ApprovalVotingParallelSenderTrait
  A abstracting trait for usage with subsystems.
• ApprovalVotingSenderTrait
  A abstracting trait for usage with subsystems.
• AssociateOutgoing
  Binds a generated type covering all declared outgoing messages, which implements #generated_outgoing: From<M> for all annotated types of a particular subsystem.
• AvailabilityDistributionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• AvailabilityDistributionSenderTrait
  A abstracting trait for usage with subsystems.
• AvailabilityRecoveryContextTrait
  Accumulative trait for a particular subsystem wrapper.
• AvailabilityRecoverySenderTrait
  A abstracting trait for usage with subsystems.
• AvailabilityStoreContextTrait
  Accumulative trait for a particular subsystem wrapper.
• AvailabilityStoreSenderTrait
  A abstracting trait for usage with subsystems.
• BitfieldDistributionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• BitfieldDistributionSenderTrait
  A abstracting trait for usage with subsystems.
• BitfieldSigningContextTrait
  Accumulative trait for a particular subsystem wrapper.
• BitfieldSigningSenderTrait
  A abstracting trait for usage with subsystems.
• CandidateBackingContextTrait
  Accumulative trait for a particular subsystem wrapper.
• CandidateBackingSenderTrait
  A abstracting trait for usage with subsystems.
• CandidateValidationContextTrait
  Accumulative trait for a particular subsystem wrapper.
• CandidateValidationSenderTrait
  A abstracting trait for usage with subsystems.
• ChainApiBackend
  Offers header utilities.
• ChainApiContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ChainApiSenderTrait
  A abstracting trait for usage with subsystems.
• ChainSelectionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ChainSelectionSenderTrait
  A abstracting trait for usage with subsystems.
• CollationGenerationContextTrait
  Accumulative trait for a particular subsystem wrapper.
• CollationGenerationSenderTrait
  A abstracting trait for usage with subsystems.
• CollatorProtocolContextTrait
  Accumulative trait for a particular subsystem wrapper.
• CollatorProtocolSenderTrait
  A abstracting trait for usage with subsystems.
• DisputeCoordinatorContextTrait
  Accumulative trait for a particular subsystem wrapper.
• DisputeCoordinatorSenderTrait
  A abstracting trait for usage with subsystems.
• DisputeDistributionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• DisputeDistributionSenderTrait
  A abstracting trait for usage with subsystems.
• GossipSupportContextTrait
  Accumulative trait for a particular subsystem wrapper.
• GossipSupportSenderTrait
  A abstracting trait for usage with subsystems.
• HeadSupportsParachains
  Whether a header supports parachain consensus or not.
• MapSubsystem
  A helper trait to map a subsystem to smth. else.
• MetricsTrait
  Subsystem- or job-specific Prometheus metrics.
• NetworkBridgeRxContextTrait
  Accumulative trait for a particular subsystem wrapper.
• NetworkBridgeRxSenderTrait
  A abstracting trait for usage with subsystems.
• NetworkBridgeTxContextTrait
  Accumulative trait for a particular subsystem wrapper.
• NetworkBridgeTxSenderTrait
  A abstracting trait for usage with subsystems.
• Priority
  Describes the priority of the message.
• ProspectiveParachainsContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ProspectiveParachainsSenderTrait
  A abstracting trait for usage with subsystems.
• ProvisionerContextTrait
  Accumulative trait for a particular subsystem wrapper.
• ProvisionerSenderTrait
  A abstracting trait for usage with subsystems.
• PvfCheckerContextTrait
  Accumulative trait for a particular subsystem wrapper.
• PvfCheckerSenderTrait
  A abstracting trait for usage with subsystems.
• RuntimeApiContextTrait
  Accumulative trait for a particular subsystem wrapper.
• RuntimeApiSenderTrait
  A abstracting trait for usage with subsystems.
• RuntimeApiSubsystemClient
  Exposes all runtime calls that are used by the runtime API subsystem.
• Spawner
  A spawner
• StatementDistributionContextTrait
  Accumulative trait for a particular subsystem wrapper.
• StatementDistributionSenderTrait
  A abstracting trait for usage with subsystems.
• Subsystem
  A trait that describes the Subsystems that can run on the Orchestra.
• SubsystemContext
  A context type that is given to the Subsystem upon spawning. It can be used by Subsystem to communicate with other Subsystems or spawn jobs.
• SubsystemSender
  Sender end of a channel to interface with a subsystem.
• TaskKind
  Task kind to launch.
• TimeoutExt
  Extends Future to allow time-limited futures.

Functions

• forward_events
  Glues together the Overseer and BlockchainEvents by forwarding import and finality notifications into the OverseerHandle.
• spawn
  Spawn task of kind self using spawner S.
• spawn_metronome_metrics
  Spawn the metrics metronome task.

Type Aliases

• InitializedOverseerBuilder
  Type used to represent a builder where all fields are initialized and the orchestra could be constructed.
• OverseerHandle
  Handle for an orchestra.
• SubsystemIncomingMessages
  Incoming messages from both the bounded and unbounded channel.
• SubsystemResult
  Ease the use of subsystem errors.
• UnpinHandle
  Keeps the state of a specific block pinned in memory while the handle is alive.

Attribute Macros

• contextbounds
• gen
• orchestra
• subsystem