Special remote programs that use GETCONFIG/SETCONFIG are recommended
to implement it.
The description is not yet used, but will be useful later when adding a way
to make initremote list all accepted configs.
configParser now takes a RemoteConfig parameter. Normally, that's not
needed, because configParser returns a parter, it does not parse it
itself. But, it's needed to look at externaltype and work out what
external remote program to run for LISTCONFIGS.
Note that, while externalUUID is changed to a Maybe UUID, checkExportSupported
used to use NoUUID. The code that now checks for Nothing used to behave
in some undefined way if the external program made requests that
triggered it.
Also, note that in externalSetup, once it generates external,
it parses the RemoteConfig strictly. That generates a
ParsedRemoteConfig, which is thrown away. The reason it's ok to throw
that away, is that, if the strict parse succeeded, the result must be
the same as the earlier, lenient parse.
initremote of an external special remote now runs the program three
times. First for LISTCONFIGS, then EXPORTSUPPORTED, and again
LISTCONFIGS+INITREMOTE. It would not be hard to eliminate at least
one of those, and it should be possible to only run the program once.
This code worked as intended, but only by accident, because of this
instance:
instance Monoid b => Monoid (x -> b) where mempty = const (mempty :: b)
Let's be explicit that we throw away the error message.
The benefit here is that external special remotes will need a
LISTCONFIGS request and response to generate their config parser,
and this avoids it being done for all the ones that don't have any
configs.
Note that, a config parser could in theory fail to parse if there are no
configs (none currently do), but a parse failure is already thrown away
when generating the remote list because it's too late. Such problems
have to be caught at initremote/enableremote time, not here.
Not yet added anything to the protocol to get a list of remote config
fields; any fields will be accepted and are available for the external
remote to use as before.
There is one minor behavior change.. Before, GETCONFIG could be passed a
field such as type, externaltype, encryption, etc, and would get the
value of that. Now, GETCONFIG only works on fields that don't have a
defined meaning to git-annex, so are passed through to the external
remote. This seems unlikely to affect any external special remotes in
practice.
preferreddir can be used with any special remote, so its parser needs to
be included in the commonFieldParsers.
initremote with uuid= changed to delete that field, so it does not
need to be included in commonFieldParsers. Note that, existing remotes
initialized before this change will have the field in remote.log.
This will not cause problems parsing, because the value will be
Accepted.
Grepping for 'Accepted "' found these, and I'm pretty sure this is all of
them.
Using field functions consistently avoids possibility of typos and also
helps ensure that all fields are added to RemoteConfigParsers (as long
as I have remembered to add them when writing the functions).
Avoids parse error when the fields are added to RemoteConfig at setup
time and it then gets parsed, also at setup time. After setup time, such
internally added fields are not a problem, because they're Accepted. So
it may not be necessary in all cases to list such internally added
fields, but I think it's a good idea to always do so.
Needed so Remote.External can query the external program for its
configs. When the external program does not support the query,
the passthrough option will make all input fields be available.
Use of Typeable means the type checker can't catch this kind of mistake,
the error is deferred to runtime.
testremote now passes on a directory special remote
Remote now contains a ParsedRemoteConfig. The parsing happens when the
Remote is constructed, rather than when individual configs are used.
This is more efficient, and it lets initremote/enableremote
reject configs that have unknown fields or unparsable values.
It also allows for improved type safety, as shown in
Remote.Helper.Encryptable where things that used to match on string
configs now match on data types.
This is a work in progress, it does not build yet.
The main risk in this conversion is forgetting to add a field to
RemoteConfigParser. That will prevent using that field with
initremote/enableremote, and will prevent remotes that already are set
up from seeing that configuration. So will need to check carefully that
every field that getRemoteConfigValue is called on has been added to
RemoteConfigParser.
(One such case I need to remember is that credPairRemoteField needs to be
included in the RemoteConfigParser.)
