Implement a new error handling library based on pkg/errors. It provides
stack saving on wrapping and exports some function to add stack saving
also to external errors.
It also implements custom zerolog error formatting without adding too
much verbosity by just printing the chain error file:line without a full
stack trace of every error.
* Add a --detailed-errors options to print error with they full chain
* Wrap all error returns. Use errors.WithStack to wrap without adding a
new messsage and error.Wrap[f] to add a message.
* Add golangci-lint wrapcheck to check that external packages errors are
wrapped. This won't check that internal packages error are wrapped.
But we want also to ensure this case so we'll have to find something
else to check also these.
Replace https://github.com/satori/go.uuid with maintained version at
https://github.com/gofrs/uuid
Since the new version uuid.NewV4 returns an error when failing to read
from the random source reader we use uuid.Must to panic on error since
it's considered an unrecoverable error.
In future, if needed, we could handle the error instead of panicking.
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.
* Rename to datamanager since it handles a complete "database" backed by an
objectstorage and etcd
* Don't write every single entry as a single file but group them in a single
file. In future improve this to split the data in multiple files of a max size.
Simone Gotti