The custom RPC middleware logic that we are going to add in the next
commits will need to log under their own sub logger so we add one with a
new subsystem name.
With the new condition and checker in place, we can give the end user
the ability to add such a custom caveat to a baked macaroon.
There won't be an RPC counterpart for this operation since all first party
caveats currently are only added on the client side.
Fixes#4383 by adding a new SafeCopyMacaroon function that correctly
clones all caveats and prevents modifications on the copy from affecting
the original.
The way the macaroon bakery library lnd uses works is that one has to
register a Checker method for each caveat name that should be supported.
Since we want to allow fully customizable custom caveats we add another
layer of naming to the caveat by splitting the condition of the "outer"
caveat into two pieces, the custom caveat name and the actual custom
caveat condition.
The custom Checker function only checks that the format is correct and
that there is a handler available for a custom condition. It does not
check the condition itself, however. If the passed in acceptor signals
acceptance of a custom caveat then the bakery accepts the macaroon as a
whole (given its signature, standard caveats and permissions are all
correct) and assumes that another component down the line will make sure
the actual custom condition of a caveat is valid.
This fixes a flake I've seen in the wild lately:
```
--- FAIL: TestBlockDifferenceFix (0.01s)
router_test.go:4335: height should have been updated to 5, instead got 4
FAIL
FAIL github.com/lightningnetwork/lnd/routing 3.865s
FAIL
```
We wrap things in an assertion loop to ensure that timing quirks don't
cause the test to fail sporadically.
This commit adds the part of the changes made in this PR:
https://github.com/lightningnetwork/lnd/pull/1783. The origin PR is
quite outdated, instead of rebasing it the relevant changes are taken
out and put into this commit.
This commit adds a check to the returned error from calling retryCheck
such that when the max number of attempts is reached, the health check
will quit.
This commit adds a missing return statement to pingHandler. This
prevents a nil pointer dereference panic from happening if an error is
returned from RegisterBlockEpochNtfn.
