CouchDB Ruby Query Server

by Matthew Lyon matt@flowerpowered.com

This is a ruby version of the CouchDB Query server. It will let you write your map and reduce functions in ruby (instead of javascript, erlang, or what have you) and eventually all your couchapp functions as well.

It is still very much a work in progress, please don't use it for anything in production yet.

Usage

In one of your CouchDB config files, add this:

[query_servers]
ruby = /path/to/ruby /path/to/bin/couchdb_view_server

If you want to just use environment ruby you can leave /path/to/ruby out.

Your design documents should look something like this:

{
    "_id": "_design/foos",
    "language": "ruby",
    "views": {
        "foos": {
            "map": "lambda{|doc| emit(doc['foo'], nil) }"
        }
    }
}

If you are going to allow people you may not necessarily trust "admin-level" access to your CouchDB install, such that they may create design documents and therefore upload their own code, you may sandbox user code with the --safe flag like so:

[query_servers]
ruby = /path/to/ruby -- /path/to/bin/couchdb_view_server --safe

All code is eval'd and run under a $SAFE level of 4 in this mode. If running in safe mode, it is preferred to run under Ruby 1.9, which has a vastly improved "trust/untrusted" model for security of objects.

Notes

Does not yet run on Ruby 1.8.6, as it requires instance_exec. Will most likely just steal Rails' implementation.

TODO

• improve safe mode support by redefining Kernel#sleep to raise.

Maybe/Someday TODO Wishlist

• implement Object#instance_exec so this can run on Ruby 1.8.6
• implement some sort of proper template system for show/list. Would likely go with Mustache. OTOH, there's nothing stopping you from doing this inside show/list yourself.

Changelog

0.8 2010-04-11

• implement log and throw methods across all proc runners
• make the design doc available to all design doc functions (basically, everything except map and reduce) (thanks, jchris)
• fixed a problem in list functions where returning a send function crashed (thanks jchris)

0.2 2010-03-25

• round out support for all function types, including validate_doc_update, update, show and list.

0.1.2 2010-03-14

• fix for multiple reduce functions being run simultaneously

0.1.1 2010-03-14

• README updates, gem version bump

0.1 2010-03-14

• Offer a "safe" flag to provide a locked-down sandbox for user code inside $SAFE level 4.

0.1pre 2 2010-03-13

• Consolidate a lot of the "in-place, get it working" code for map/reduce to the View module.

0.1pre 1 2010-03-07

• Basic implementation of map/reduce working.