I believe this closes#297 as well.
I have been working on adding testing of migrations and it requires acquiring
the lock in mysql multiple times to go up and down. After nailing this down to
GET_LOCK returning a failure for every subsequent GET_LOCK call after the
first, I decided it was time to rtfm and lo and behold:
https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_release-lock
RELEASE_LOCK will not work if called from a different thread than GET_LOCK.
The simplest solution using the golang database/sql pkg appears to be to just
get a single conn to use for every operation. since migrations are happening
sequentially, I don't think this will be a performance hit (possible
improvement). now calling Lock() and Unlock() multiple times will work;
prior to this patch, every call to RELEASE_LOCK would fail. this required
minimal changes to use the *sql.Conn methods instead of the *sql.DB methods.
other changes:
* upped time out to 10s on GET_LOCK, 1s timeout can too easily leave us in a
state where we think we have the lock but it has timed out (during the
operation).
* fixes SetVersion which was not using the tx it was intending to, and fixed a
bug where the transaction could have been left open since Rollback or Commit
may never have been called.
I added a test but it does not seem to come up in the previous patch, at least
easily, I tried some shenanigans. At least, this behavior should be fixed with
this patch and hopefully the test / comment is advisory enough.
thank you for maintaining this library, it has been relatively easy to
integrate with and most stuff works (pg works great :)
cockroach-go made a backwards-incompatible change to their transaction
function signatures, which was causing the cockroach instrumentation
to fail.
Updates the signature to match the cockraoch-go change.
Adds a readme to the cockroachdb database package, following the
postgres readme style.
Also adds the ability to force acquisition of the migration lock
via a connect URL parameter/WithInstance config, to allow for fixing
cases where an implementation error causes the schema lock to not
be released.
Lastly, tweaks the CLI readme to include information on building a
CLI for databases other than postgres.
Adds the ability to specify a series of commands to run as part
of the docker image execution, and allows for retrieving a mapping
of an exposed via the port bound within the container.
Adds support for CockroachDB. Cockroach uses the postges wire
protocol and has a large amount of common SQL functionality shared
with Postgres, so much of the postgres code was able to be copied
and modified.
Since the protocol is used in determining the driver, and the
Postgres protocol is also used by Cockroach, new connect string
prefixes were added: cockroach:// cockroachdb:// and
crdb-postgres://. These fake protocol strings are replaced in
the connect function with the correct `postgres://` protocol.
TODO: Tests needed (Cockroach has a docker image, so this shouldn't
be too hard)
