Transport Auto Retry Listening

[jacobheun]

This has been brought up in several different issues across libp2p and js-ipfs. We need to be able to handle unstable listening of transports, and report that back to consumers of the libp2p api.

Goals

• Support intermittent availability of listening connections, such as for remote listening.
• Allow for automatic retry of connections when offline.
• Add hooks for developers to check connectivity status.

Needed Updates

• Update interface-transport to allow for multi address listening
• Update interface-transport to handle automatic retry of listening with jitter
  • Update interface-transport to take an option for overriding retry
  • Update interface-transport to take an option failure tolerance (error_all_failed, error_some_failed, always_retry)
• Update switch to use the new interface-transport api
• Update all transports to the new interface-transport api
• Update libp2p to expose the retry interface and necessary configurations

Scenarios

1. Websocket browser node starts offline

• The node starts and no listening connections are able to be made
• The websocket transport emits ERROR_ALL_LISTENERS_FAILED
  • Switch is configured to not fatally error on listener failures
  • Switch tracks the error state of each transport type (websocket in state Retry)
  • The state includes metadata for the retry logic (when is the next retry)
  • The websocket transport automatically retries after a TBD backoff interval
• After x attempts, websocket is able to listen
  • The websocket transport emits a state change of Listening
  • Switch updates the listening status of the websocket transport via its TransportManager
  • Switch emits the change in its listening status as it now has an active listener
• Libp2p emits its change in listening state

2. Wifi Connection Drops

TODO

3. Computer sleep

TODO

Notes

Transports

States

1. Closed - All listeners are closed
2. Connecting - Initial listening attempts are being made
3. Retry - Listening failed, retry will occur automatically and is manually triggerable
4. Retrying - Attempting to listen again
5. Listening - Listeners are active
6. Closing - Listeners are being closed

Reference Issues

ipfs/js-ipfs#1837
https://github.com/libp2p/interface-transport/issues/41
libp2p/js-libp2p-websocket-star#61

[maschad]

Closing as we would rather that nodes fail on start up if listeners fail to initialize and also transports with transient addresses can be tracked with the listener open/close events emitted on the Libp2p object.