This change encodes a bunch of invariants in the type system,
and adds explicit failure states for:
* a closed oneshot,
* bugs in the initialization code.
Use `ServiceExt::oneshot` to perform state requests.
Explain that `ServiceExt::call_all` calls `poll_ready` internally.
Document a state service invariant imposed by `ServiceExt::call_all`.
* Rewrite GetData handling to match the zcashd implementation
`zcashd` silently ignores missing blocks, but sends found transactions
followed by a `NotFound` message:
e7b425298f/src/main.cpp (L5497)
This is significantly different to the behaviour expected by the old
Zebra connection state machine, which expected `NotFound` for blocks.
Also change Zebra's GetData responses to peer request so they ignore
missing blocks.
* Stop hanging on incomplete transaction or block responses
Instead, if the peer sends an unexpected block, unexpected transaction,
or NotFound message:
1. end the request, and return a partial response containing any items
that were successfully received
2. if none of the expected blocks or transactions were received, return
an error, and close the connection
* implement inbound `FindBlocks`
* Handle inbound peer FindHeaders requests
* handle request before having any chain tip
* Split `find_chain_hashes` into smaller functions
Add a `max_len` argument to support `FindHeaders` requests.
Rewrite the hash collection code to use heights, so we can handle the
`stop` hash and "no intersection" cases correctly.
* Split state height functions into "any chain" and "best chain"
* Rename the best chain block method to `best_block`
* Move fmt utilities to zebra_chain::fmt
* Summarise Debug for some Message variants
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
The Inbound service only needs the network setup for some requests, but
it can service other requests without it. Making it return
Poll::Pending until the network setup finishes means that initial
network connections may view the Inbound service as overloaded and
attempt to load-shed.
The original version of this commit ran into
https://github.com/rust-lang/rust/issues/64552
again. Thanks to @yaahc for suggesting a workaround (using futures combinators
to avoid writing an async block).
Remove the seed command entirely, and make the behavior it provided
(responding to `Request::Peers`) part of the ordinary functioning of the
start command.
The new `Inbound` service should be expanded to handle all request
types.
teor
Jane Lusby
Alfredo Garcia
Henry de Valence