Implement configstore maintenance mode and export/import.
When configstore is set in maintenance mode it'll start only the maintenance and
export/import handlers.
Setting maintenance mode will set a key in etcd so all the configstore instances
will detect it and enter in maintenance mode. This is done asyncronously so it
could take some time (future improvements will add some api to show all the
configstore states)
Export is always available and will export the datamanager contents.
Import is available only during maintenance, given a datamanager export will
import it and reset etcd to this import state.
Use the go sql context functions (ExecContext, QueryContext etc...)
The context is saved inside Tx so the library users should only pass it one time
to the db.Do function.
In runservice readdb Run method we could end with a deadlock if two of the
goroutines that call HandleEvents.* try to write to the errCh at the same
time before the errCh is read. If this happens one of the two will be blocked on
writing to the channel but the read won't happen since it'll blocked by
wg.Wait().
Fix this doing:
* use a buffered channel large as the number of executed goroutines.
* create a new errCh at every loop (so we'll ignore later errors after the first
one)
Note: we could also use a non blocking send to avoid this situation but we
should also start the wg.Wait before the goroutines or earlier errors could be
lost causing another kind of hang.
* Don't make cors enabled on all (*) by default.
* Handle related web.allowedOrigins options
* Only the gateway api should be called by a browser so setup the cors handler
only on it
* Override the provided remotesource id with the current one (it could not be
provided or provided with a different id but the remotesource ref is the way to
get the current remote source).
* When changing remotesource name check that a remote source with the new name
does not already exist.
Don't put datamanager base dirs inside the root of the ost but use a base path.
Let's do it now before releasing since this is a breaking change that requires
moving the ost data to the new path
Currently we aren't setting a basepath and it wasn't always correctly handled.
Fix missing basepath handling and improve tests to also use a non empty
basepath.
ErrInternal is an internal error that should be provided to the user (http api
will return a 500 with the error message)
It'll be used for any kind of error that are not auth or bad requests (like
errors to communicate to another service)
split data files in multiple files of a max size (default 10Mib)
In this way every data snapshot will change only the datafiles that have some
changes instead of the whole single file.
Don't create an ErrFromRemote wrapping the returned error but
wrap the ErrFromRemote
Also use xerrors Is/As to get the underlying error to return to api clients
while maintaining context for logging
Just a raw replace of "github.com/pkg/errors".
Next steps will improve errors (like remote errors, api errors, not exist errors
etc...) to leverage its functionalities
rename the previous posix storage to posixflat and make it currently not user
selectable (since I'm not sure it's really worth using it).
The new posix storage uses the filesystem without any escaping so it's not a
real flat namespace.
This isn't a real issue since also minio is not a flat namespace and we are so
forced to use it like a hierarchycal filesystem.
Simone Gotti