This commit changes how we locate the next migration height by including
the scenario where `lnd@v0.15.0` is active. In the new version, we will
see a mixed of new and old logs under the same open channel bucket.
Hence, we need to alter how we locate the next un-migrated height.
This commit adds the migration that's used to convert the old revocation
logs into the new format. The migration is fault-tolerant, meaning the
process can be interrupted and the migration will pick up what's left
when running again. We also cap how many records to be processed in each
db transaction to prevent OOM.
This commit adds supporting functions that will be used in the unit
test. The testing data are also added as hard-coded. We choose to copy
the most of the testing data from our itest results such that a) they
are "real" data that can be used to calculate scripts and b) we preserve
the result generated by the current code so a future change won't affect
our test.
This commit adds several utility functions to assist the migration. In
particular, an updateLocator is added to gives us the next un-migration
position in our buckets. This locator helps us to continue the job
in case of an interrupted migration. It also serves as an indicator on
whether the migration is finished or not.
This commit adds relevant code from the revocation_log.go and the
package lnwallet. The code is needed to migrate the data, and we choose
to copy the code instead of importing to preserve the version such that
a future change won't affect current migration. An alternative would be
tagging each of the packages imported.
