The exposed AddNode, AddEdge and UpdateEdge methods of the Builder are
currently synchronous since even though they pass messages to the
network handler which spins off the handling in a goroutine, the public
methods still wait for a response from the handling before returning.
The only part that is actually done asynchronously is the topology
notifications.
We previously tried to simplify things in [this
commit](d757b3bcfc)
but we soon realised that there was a reason for sending the messages to
the central/synchronous network handler first: it was to ensure
consistency for topology clients: ie, the ordering between when there is
a new topology client or if it is cancelled needs to be consistent and
handled synchronously with new network updates. So for example, if a new
update comes in right after a topology client cancels its subscription,
then it should _not_ be notified. Similariy for new subscriptions. So
this commit was reverted soon after.
We can, however, still simplify things as is done in this commit by
noting that _only topology subscriptions and notifications_ need to be
handled separately. The actual network updates do not need to. So that
is what is done here.
This refactor will make moving the topology subscription logic to a new
subsystem later on much easier.
This commit restricts the graph CRUD interface such that one can only
add a proof to a channel announcement and not update any other fields.
This pattern is better suited for SQL land too.
This commit is a pure refactor. We move the transaction validation
(existence, spentness, correctness) from the `graph.Builder` to the
gossiper since this is where all protocol level checks should happen.
All tests involved are also updated/moved.
In preparation for an upcoming commit which will move all channel
funding tx validation to the gossiper, we first move the helper method
which helps build the expected funding transaction script based on the
fields in the channel announcement. We will still want this script later
on in the builder for updating the ChainView though, and so we pass this
field along with the ChannelEdgeInfo. With this change, we can remove
the TapscriptRoot field from the ChannelEdgeInfo since the only reason
it was there was so that the builder could reconstruct the full funding
script.
This is in preparation for the commit where we move across all the
funding tx validation so that we can test that we are correctly updating
the zombie index.
The `graph.Builder`'s `addZombieEdge` method is currently called during
funding transaction validation for the case where the funding tx is not
found. In preparation for moving this code to the gossiper, we export
the method and add it to the ChannelGraphSource interface so that the
gossiper will be able to call it later on.
In preparation for moving funding transaction validiation from the
Builder to the Gossiper in later commit, we first convert these graph
Error Codes to normal error variables. This will help make the later
commit a pure code move.
The point of the `graph.Builder`'s `networkHandler` goroutine is to
ensure that certain requests are handled in a synchronous fashion.
However, any requests received on the `networkUpdates` channel, are
currently immediately handled in a goroutine which calls
`handleNetworkUpdate` which calls `processUpdate` before doing topology
notifications. In other words, there is no reason for these
`networkUpdates` to be handled in the `networkHandler` since they are
always handled asynchronously anyways. This design is most likely due to
the fact that originally the gossiper and graph builder code lived in
the same system and so the pattern was copied across.
So in this commit, we just remove the complexity. The only part we need
to spin off in a goroutine is the topology notifications.
In this commit, we remove the `processUpdate` method which handles each
announement type (node, channel, channel update) in a separate switch
case. Each of these cases currently has a non-trivial amount of code.
This commit creates separate methods for each message type we want to
handle instead. This removes a level of indentation and will make things
easier to review when we start editing the code for each handler.
This omits calls to InitJobDependencies, SignalDependants, and
WaitForDependants. These changes have been made here because
the router / builder code does not actually need job dependency
management. Calls to the builder code (i.e. AddNode, AddEdge,
UpdateEdge) are all blocking in the gossiper. This, combined
with the fact that child jobs are run after parent jobs in the
gossiper, means that the calls to the router will happen in the
proper dependency order.
Find and replace all nolint instances refering to the `lll` linter and
replace with `ll` which is the name of our custom version of the `lll`
linter which can be used to ignore log lines during linting.
The next commit will do the configuration of the custom linter and
disable the default one.
and the same for ChannelStateDB.FetchChannel. Most of the calls to these
methods provide a `nil` Tx anyways. The only place that currently
provides a non-nil tx is in the `localchans.Manager`. It takes the
transaction provided to the `ForAllOutgoingChannels` callback and passes
it to it's `updateEdge` method. Note, however, that the
`ForAllOutgoingChannels` call is a call to the graph db and the call to
`updateEdge` is a call to the `ChannelStateDB`. There is no reason that
these two calls need to happen under the same transaction as they are
reading from two completely disjoint databases. And so in the effort to
completely split untangle the relationship between the two databases, we
now dont use the same transaction for these two calls.
All the structs defined in the `channeldb/models` package are graph
related. So once we move all the graph CRUD code to the graph package,
it makes sense to have the schema structs there too. So this just moves
the `models` package over to `graph/db/models`.
This commit is a large refactor that moves over various responsibilities
from the ChannelRouter to the graph.Builder. These include all graph
related tasks such as:
- graph pruning
- validation of new network updates & persisting new updates
- notifying topology update clients of any changes.
This is a large commit but:
- many of the files are purely moved from `routing` to `graph`
- the business logic put in the graph Builder is copied exactly as is
from the ChannelRouter with one exception:
- The ChannelRouter just needs to be able to call the Builder's
`ApplyChannelUpdate` method. So this is now exported and provided to
the ChannelRouter as a config option.
- The trickiest part was just moving over the test code since quite a
bit had to be duplicated.
This is preparation for an upcoming commit that will move over various
responsibilities from the ChannelRouter to the graph Builder. So that
that commit can be a pure code-move commit, the template for the new
sub-system is added up front here.
