More update: I started producing a plugin template repo that people can clone to build their own plugins along with a comprehensive README.md:
https://github.com/janl/my-first-couchdb-plugin
The idea is to move the README to the CouchDB docs eventually and ship
the plugin template with CouchDB, so people can get started easily.
Best
Jan
--
On Aug 3, 2013, at 17:53 , Simon Metson <[email protected]> wrote:
> :)
>
>
> On Saturday, 3 August 2013 at 14:21, Jan Lehnardt wrote:
>
>> Couldn’t help but implement it. It’s in the branch now.
>>
>> Jan
>> --
>>
>> On Aug 3, 2013, at 08:12 , Simon Metson <[email protected]> wrote:
>>
>>> Sounds good to me.
>>>
>>>
>>> On Saturday, 3 August 2013 at 00:56, Jan Lehnardt wrote:
>>>
>>>>
>>>> On Aug 3, 2013, at 00:02 , Russell Branca <[email protected]
>>>> (mailto:[email protected])> wrote:
>>>>
>>>>> This is fantastic, Jan! Glad to see this coming along.
>>>>>
>>>>> One of the goals with Fauxton has always been to make it easy for plugins
>>>>> to extend the interface and provide new functionality. I've been toying
>>>>> with the idea of having a _fauxton db that plugins install to as docs with
>>>>> attachments, but that's for a different thread. The general idea here is
>>>>> that a plugin will be able to extend Fauxton by adding a new page with
>>>>> it's
>>>>> own functionality, or hook into existing pages to extend other areas.
>>>>>
>>>>> For instance, you could have a couchdb-lucene plugin that hooks into the
>>>>> databases list and allows you to add interfaces for building full text
>>>>> indexes and searching on existing indexes. Or you could have a dedicated
>>>>> page for Geocouch, or whatever.
>>>>>
>>>>> The functionality is there, but it's still a bit of a manual process, so
>>>>> we'll need to make it more dynamic and smooth out the rough edges.
>>>>>
>>>>> I'm very excited to see progress being made on plugins, great work!
>>>>
>>>> Thanks, I’m glad you like this! :)
>>>>
>>>> Another way to get the Fauxton plugin loaded would be to extend the
>>>> /_plugins API endpoint, so Fauxton could request GET
>>>> /_plugins/<pluginname>/
>>>> and it would serve <couchdblibdir>/plugins/<pluginname/priv/www which is
>>>> just a place for Fauxton-enabled plugins.
>>>>
>>>> Fauxton would walk /_config/plugins/ to get to a list of plugins.
>>>>
>>>> In fact that should be pretty simple to set up.
>>>>
>>>> For now I am trying to avoid having a custom database for this, mostly
>>>> because I don’t think there are many advantages (e.g. replication of
>>>> plugins?) and code complexity. These priorities might change in the
>>>> future, but for now I am happy to get this working at all :)
>>>>
>>>> If you are okay with the above plan of serving plugin HTML/JS/CSS from
>>>> /_plugins/<pluginname>, I’m happy to add this to the branch.
>>>>
>>>> Best
>>>> Jan
>>>> --
>>>>
>>>>
>>>>
>>>>>
>>>>>
>>>>> -Russell
>>>>>
>>>>>
>>>>> On Fri, Aug 2, 2013 at 2:17 PM, Jan Lehnardt <[email protected]
>>>>> (mailto:[email protected])> wrote:
>>>>>
>>>>>> And a few more (from COUCHDB-1867):
>>>>>>
>>>>>> - Add uninstall, incl. Futon UI.
>>>>>> - Only install a plugin if the source and target CouchDB version matches.
>>>>>> - Rebase against master.
>>>>>>
>>>>>> * * *
>>>>>>
>>>>>> This concludes my list for a Minimally Viable Plugin feature. (See the
>>>>>> original email or README.md (http://README.md)* for the roadmap)
>>>>>>
>>>>>> I’d appreciate some more reviews & feedback**, but other than that, I’d
>>>>>> be
>>>>>> happy to ship this as an experimental feature in any next release.
>>>>>>
>>>>>> *
>>>>>> https://github.com/janl/couchdb/blob/1867-feature-plugins/src/couch_plugins/README.md#roadmap
>>>>>> **
>>>>>> https://github.com/janl/couchdb/compare/apache:master...1867-feature-plugins
>>>>>>
>>>>>>
>>>>>> Best
>>>>>> Jan
>>>>>> --
>>>>>>
>>>>>> On Aug 1, 2013, at 19:34 , Jan Lehnardt <[email protected]
>>>>>> (mailto:[email protected])> wrote:
>>>>>>
>>>>>>> A few updates:
>>>>>>>
>>>>>>> By Bob Ippolito / @etrepum:
>>>>>>> - Plugins are now installed in libdir (instead of /tmp).
>>>>>>> - Config loading is now done with proper .ini files.
>>>>>>> - Various cleanups and code review (Thanks!).
>>>>>>>
>>>>>>> Mine (most suggested by Bob):
>>>>>>> - `plugins.html` now shows you if a plugin is already installed.
>>>>>>> and which version, if it doesn’t match the installable one.
>>>>>>> - The Install button now disables after an installation.
>>>>>>> - Plugins are now registered with couch_config as
>>>>>>> /_config/plugins/name = version
>>>>>>> - Updated `couch-config` to print --erlang-version and --erl-bin
>>>>>>> - Updated the geocouch plugin to use the new options in
>>>>>>> `couch-config`.
>>>>>>> - Added Bob Ippolito’s couchperuser plugin to Futon.
>>>>>>>
>>>>>>>
>>>>>>> Best
>>>>>>> Jan
>>>>>>> --
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Jul 31, 2013, at 19:07 , Jan Lehnardt <[email protected]
>>>>>>> (mailto:[email protected])> wrote:
>>>>>>>
>>>>>>>> Heya,
>>>>>>>>
>>>>>>>> I couldn’t help myself thinking about plugin stuff and ended up
>>>>>>>> whipping up a proof of concept.
>>>>>>>>
>>>>>>>> Here’s a <1 minute demo video:
>>>>>>>>
>>>>>>>> https://dl.dropboxusercontent.com/u/82149/couchdb-plugins-demo.mov
>>>>>>>>
>>>>>>>> Alternative encoding:
>>>>>>>>
>>>>>>>> https://dl.dropboxusercontent.com/u/82149/couchdb-plugins-demo.m4v)
>>>>>>>>
>>>>>>>>
>>>>>>>> In my head the whole plugin idea is a very wide area, but I was so
>>>>>>>> intrigued by the idea of getting something running with a click on a
>>>>>>>> button in Futon. So I looked for a minimally viable plugin system.
>>>>>>>>
>>>>>>>>
>>>>>>>> ## Design principles
>>>>>>>>
>>>>>>>> It took me a day to put this all together and this was only possible
>>>>>>>> because I took a lot of shortcuts. I believe they are all viable for a
>>>>>>>> first iteration of a plugins system:
>>>>>>>>
>>>>>>>> 1. Install with one click on a button in Futon (or HTTP call)
>>>>>>>> 2. Only pure Erlang plugins are allowed.
>>>>>>>> 3. The plugin author must provide a binary package for each Erlang
>>>>>>>> (and,
>>>>>>>> later, each CouchDB version).
>>>>>>>> 4. Complete trust-based system. You trust me to not do any nasty things
>>>>>>>> when you click on the install button. No crypto, no nothing. Only
>>>>>>>> people who can commit to Futon can release new versions of plugins.
>>>>>>>> 5. Minimal user-friendlyness: won’t install plugins that don’t match
>>>>>>>> the current Erlang version, gives semi-sensible error messages
>>>>>>>> (wrapped in a HTTP 500 response :)
>>>>>>>> 6. Require a pretty strict format for binary releases.
>>>>>>>>
>>>>>>>>
>>>>>>>> ## Roadmap
>>>>>>>>
>>>>>>>> Here’s a list of things this first iterations does and doesn’t do:
>>>>>>>>
>>>>>>>> - Pure Erlang plugins only. No C-dependencies, no JavaScript, no
>>>>>> nothing.
>>>>>>>> - No C-dependencies.
>>>>>>>> - Install a plugin via Futon (or HTTP call). Admin only.
>>>>>>>> - A hardcoded list of plugins in Futon.
>>>>>>>> - Loads a pre-packaged, pre-compiled .tar.gz file from a URL.
>>>>>>>> - Only installs if Erlang version matches.
>>>>>>>> - No security checking of binaries.
>>>>>>>> - No identity checking of binaries.
>>>>>>>>
>>>>>>>> Here are a few things I want to add before I call it MVP*:
>>>>>>>>
>>>>>>>> - Uninstall a plugin via Futon (or HTTP call). Admin only.
>>>>>>>> - Only installs if CouchDB version matches.
>>>>>>>> - Binaries must be published on *.apache.org (http://apache.org).
>>>>>>>> - Register installed plugins in the config system.
>>>>>>>> - Make sure plugins start with the next restart of CouchDB.
>>>>>>>> - Show when a particular plugin is installed.
>>>>>>>>
>>>>>>>> *MVP hopefully means you agree we can ship this with a few warnings
>>>>>>>> so people can get a hang of it.
>>>>>>>>
>>>>>>>> Here is a rough list of features squared against future milestones:
>>>>>>>>
>>>>>>>> Milestone 2: Be creator friendly
>>>>>>>> - Make it easy to build a CouchDB plugin by providing one or more easy
>>>>>>>> to start templates.
>>>>>>>> - Make it easy to publish new plugins and new versions of existing
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> plugins.
>>>>>>>> - Make it easy to supply packages for multiple Erlang & CouchDB
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> versions.
>>>>>>>>
>>>>>>>> Milestone 3: Public registry
>>>>>>>> - Instead of hardcoding a list of plugins into Futon/Fauxton, we load
>>>>>>>> a list of applicable plugins from a central (and configurable)
>>>>>>>> plugins repository.
>>>>>>>> - This allows plugin authors to publish new plugins and new versions
>>>>>>>> of existing plugins independently.
>>>>>>>>
>>>>>>>> Milestone 4: Other Languages
>>>>>>>> - Figure out how to handle C-dependencies for Erlang plugins.
>>>>>>>> - Figure out how to allow other language plugins
>>>>>>>> (c.f. non-JS query servers)
>>>>>>>>
>>>>>>>> Milestone X: Later
>>>>>>>> - Add some account/identity/maybe crypto-web-of-trust system for
>>>>>>>> authors to publish “legit” plugins.
>>>>>>>> - Sign & verify individual releases.
>>>>>>>>
>>>>>>>> A few more things that can happen concurrently depending on what
>>>>>>>> plugins require:
>>>>>>>> - Integrate Erlang/JS tests in the installation
>>>>>>>> - Integrate docs
>>>>>>>>
>>>>>>>>
>>>>>>>> ## How it works
>>>>>>>>
>>>>>>>> This plugin system lives in `src/couch_plugins` and is a tiny CouchDB
>>>>>>>> module.
>>>>>>>>
>>>>>>>> It exposes one new API endpoint `/_plugins` that an admin user can
>>>>>>>> POST to.
>>>>>>>>
>>>>>>>> The additional Futon page lives at /_utils/plugins.html it is
>>>>>>>> hardcoded.
>>>>>>>>
>>>>>>>> Futon (or you) post an object to `/_plugins` with four properties:
>>>>>>>>
>>>>>>>> {
>>>>>>>> "name": "geocouch", // name of the plugin, must be unique
>>>>>>>> "url": "http://people.apache.org/~jan";, // “base URL” for plugin
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> releases (see below)
>>>>>>>> "version": "couchdb1.2.x_v0.3.0-11-gd83ba22", // whatever version
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> internal to the plugin
>>>>>>>> "checksums": {
>>>>>>>> "R15B03": "ZetgdHj2bY2w37buulWVf3USOZs=" // base64’d sha hash
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> over the binary
>>>>>>>> }
>>>>>>>> }
>>>>>>>>
>>>>>>>> `couch_plugins` then attempts to download a .tar.gz from this
>>>>>>>> location:
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> http://people.apache.org/~jan/geocouch-couchdb1.2.x_v0.3.0-12-g4ea0bea-R15B03.tar.gz
>>>>>>>>
>>>>>>>> It should be obvious how the URL is constructed from the POST data.
>>>>>>>> (This url is live, feel free to play around with this tarball).
>>>>>>>>
>>>>>>>> Next it calculates the sha hash for the downloaded .tar.gz file and
>>>>>>>> matches it against the correct version in the `checksums` parameter.
>>>>>>>>
>>>>>>>> If that succeeds, we unpack the .tar.gz file (currently in `/tmp`,
>>>>>>>> need to find a better place for this) and adds the extracted directory
>>>>>>>> to the Erlang code path
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> (`code:add_path("/tmp/couchdb_plugins/geocouch-couchdb1.2.x_v0.3.0-12-g4ea0bea-R15B03/ebin")`)
>>>>>>>> and loads the included application (`application:load(geocouch)`).
>>>>>>>>
>>>>>>>> Then it looks into the `./config` directory that lives next to `ebin/`
>>>>>>>> in the plugin directory for a file `config.erlt` (“erl-terms”). with a
>>>>>>>> list of configuration parameters to load. We parse the file and set
>>>>>>>> the config directives one by one.
>>>>>>>>
>>>>>>>> If that all goes to plan, we report success back to the HTTP caller.
>>>>>>>>
>>>>>>>> That’s it! :)
>>>>>>>>
>>>>>>>> It’s deceptively simple, probably does a few things very wrong and
>>>>>>>> leaves a few things open (see above).
>>>>>>>>
>>>>>>>> One open question I’d like an answer for is finding a good location to
>>>>>>>> unpack & install the plugin files that isn’t `tmp`. If the answer is
>>>>>>>> different for a pre-BigCouch/rcouch-merge and post-BigCouch/rcouch-
>>>>>>>> merge world, I’d love to know :)
>>>>>>>>
>>>>>>>>
>>>>>>>> ## Code
>>>>>>>>
>>>>>>>> The main branch for this is 1867-feature-plugins:
>>>>>>>>
>>>>>>>> ASF:
>>>>>> https://git-wip-us.apache.org/repos/asf?p=couchdb.git;a=log;h=refs/heads/1867-feature-plugins
>>>>>>>> GitHub: https://github.com/janl/couchdb/compare/1867-feature-plugins
>>>>>>>>
>>>>>>>> I created a branch on GeoCouch that adds a few lines to its `Makefile`
>>>>>>>> that shows how a binary package is built:
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> https://github.com/janl/geocouch/compare/couchbase:couchdb1.3.x...couchdb1.3.x-plugins
>>>>>>>>
>>>>>>>> * * *
>>>>>>>>
>>>>>>>> I hope you like this :) Please comment and improve heavily!
>>>>>>>>
>>>>>>>> Let me know if you have any questions :)
>>>>>>>>
>>>>>>>> If you have any criticism, please phrase it in a way that we can use
>>>>>>>> to improve this, thanks!
>>>>>>>>
>>>>>>>> Best,
>>>>>>>> Jan
>>>>>>>> --
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
>
>
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