Add ModifyIndex & X-Consul-Index to all responses about diplomat

[cablehead]

Hi 😄

I think the way to go is to first expose all of the available features Consul offers, with a Ruby centric API and then layer additional, more convenient APIs on top of that.

For python-consul, the approach I've taken is to return all the available JSON for calls that return JSON, and for X-Consul-Index, to return a tuple of (index, data) from all calls that support blocking reads.

e.g. kv.get returns:

    (index, {
        "CreateIndex": 100,
        "ModifyIndex": 200,
        "LockIndex": 200,
        "Key": "foo",
        "Flags": 0,
        "Value": "bar",
        "Session": "adf4238a-882b-9ddc-4a9d-5b6758e4159e"
    })

Returning a tuple is pretty Pythonic. I'm not sure what a more Ruby centric way would be?

This is a little verbose. e.g.

    index, data = c.kv.get('foo')
   # make use of data['Value']

Isn't nearly as nice as:

foo = Diplomat.get('foo')
# => "bar"

if all you want is a KV store. But it does allow you to use all of Consul's features. Particularly long polling to dynamically listen for updates, and it makes ModifyIndex available for cas updates.

Once the API is in place to expose the raw Consul features, additional more convenient APIs like Diplomat's current API can be layered on top.

[galthaus]

How about this?

Get signature:
get(key, scope=:first, options={})
Input:
options[:index] = string
options[:wait] = string time component
Return
options[:index] is modified on return to be the returned index.

This keeps get happy, doesn't change too much code, gives access to all values over time. The options seems to be the ruby-ish standard way to pass in info and deal with expansion. We could move in scope, but that would break existing things.

If you don't like the writing into an input focused structure, we could add a meta hash to return the requests meta data. Put index, last-contact, ...

I working on this now. I don't really care which I just need long polling. :-)

[johnhamelink]

@galthaus looks nice 👍

Looking forward to seeing that PR!

[johnhamelink]

Solved thanks to #11

[johnhamelink]

Released in version 0.2.2: https://rubygems.org/gems/diplomat/versions/0.2.2