This commit refactors `collectResultAsync` such that this method is now
only responsible for collecting results from the switch. The method
`decideNextStep` is expanded to process these results in the same
goroutine where we fetch the payment from db, to make sure the lifecycle
loop always have a consistent view of a given payment.
In a rare case when the critical log is triggered when using postgres as
db backend, the `payment` could be nil cause the server is shutting
down, causing the payment fetching to return an error. We now cache its
state before fetching it from the db.
With this commit we move the traffic shaper definition from the routing
package to the HTLC switch package as a preparation for being able to
use it there as well.
At the same time we rename it to AuxTrafficShaper to be more in line
with the other auxiliary components.
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.
In this commit we set up the payment loop context
according to user-provided parameters. The
`cancelable` parameter indicates whether the user
is able to interrupt the payment loop by cancelling
the server stream context. We'll additionally wrap
the context in a deadline if the user provided a
payment timeout.
We remove the timeout channel of the payment_lifecycle.go
and in favor of the deadline context.
This commit adds unit tests for `resumePayment`. In addition, the
`resumePayment` has been split into two parts so it's easier to be
tested, 1) sending the htlc, and 2) collecting results. As seen in the
new tests, this split largely reduces the complexity involved and makes
the unit test flow sequential.
This commit also makes full use of `mock.Mock` in the unit tests to
provide a more clear testing flow.
This commit adds a new interface method `TerminalInfo` and changes its
implementation to return an `*HTLCAttempt` so it includes the route for
a successful payment. Method `GetFailureReason` is now removed as its
returned value can be found in the above method.
This commit adds a new struct, `stateStep`, to decide the workflow
inside `resumePayment`.
It also refactors `collectResultAsync` introducing a new channel
`resultCollected`. This channel is used to signal the payment
lifecycle that an HTLC attempt result is ready to be processed.
This commit makes sure we only fail attempt inside `handleSwitchErr` to
ensure the orders in failing payment and attempts. It refactors
`collectResult` to return `attemptResult`, and expands `handleSwitchErr`
to also handle the case where the attemptID is not found.
This commit refactors the `resumePayment` method by adding the methods
`checkTimeout` and `requestRoute` so it's easier to understand the flow
and reason about the error handling.
This commit removes the method `launchShard` and splits its original
functionality into two steps - first create the attempt, second send the
attempt. This enables us to have finer control over "which error is
returned from which system and how to handle it".
This commit starts handling switch error inside `sendAttempt` when an
error is returned from sending the HTLC. To make sure the updated
`HTLCAttempt` is always returned to the callsite, `handleSwitchErr` now
also returns a `attemptResult`.
This commit removes the `launchOutcome` and `shardResult` and uses
`attemptResult` instead. This struct is also used in `failAttempt` so we
can future distinguish critical vs non-critical errors when handling
HTLC attempts.
`handleSwitchErr` is now responsible for failing the given HTLC attempt
after deciding to fail the payment or not. This is crucial as
previously, we might enter into a state where the payment's HTLC has
already been marked as failed, and while we are marking the payment as
failed, another HTLC attempt can be made at the same time, leading to
potential stuck payments.
This commit removes the unclear abstraction `shardHandler` that's used
in our payment lifecycle. As we'll see in the following commits,
`shardHandler` is an unnecessary layer and everything can be cleanly
managed inside `paymentLifecycle`.
This commit refactors the params used in lifecycle to prefer
`HTLCAttempt` over `HTLCAttemptInfo`. This change is needed as
`HTLCAttempt` also wraps settled and failure info, which is useful in
the following commits.
This commit turns `MPPayment` into an interface inside `routing`. Having
this interface gives us the benefit to write more granular unit tests
inside payment lifecycle. As seen from the modified unit tests, several
hacky ways of testing the `SendPayment` method is now replaced by a mock
over `MPPayment`.
This commit adds a new method, `NeedWaitAttempts`, to properly decide
whether we need to wait for the outcome of htlc attempts based on the
payment's current state.
This commit moves the struct `paymentState` used in `routing` into
`channeldb` and replaces it with `MPPaymentState`. In the following
commit we'd see the benefit, that we don't need to pass variables back
and forth between the two packages. More importantly, this state is put
closer to its origin, and is strictly updated whenever a payment is read
from disk. This approach is less error-prone comparing to the previous
one, which both the `payment` and `paymentState` need to be updated at
the same time to make sure the data stay consistant in a parallel
environment.
This commit moves the creations of hop and htlcAdd message from
`createNewPaymentAttempt` to `sendPaymentAttempt` to clean up the code
and further pave the way to decomposite the lifecycle.
