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Contact is a language and interactive shell for Riak.
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What is it?

Contact is a language and interactive shell for Riak.


Intro to Contact Screencast


This is a prototype and SHOULD NOT BE USED IN PRODUCTION.

See the TODO section below.


  1. An easy syntax for all Riak operations
  2. An easy way to incorporate text, JSON, XML, Javascript into a Contact script file without escape-character madness.
  3. A console that supports simple command completion and history.
  4. Extensible object output, conflict resolution and retrier with Javascript (via Mozilla Rhino)

Language Grammar

See: Contact.g4

Contact uses an Antlr 4 grammar under the hood for all lexical + semantic goodness.


Be sure you JAVA_HOME is set. You'll need at least JDK 1.6 and Apache Maven to build Contact.

At the console, type:

mvn package

Hello world

After you've built Contact, just type:



At a Contact console prompt, try one of:


help commands

help <commandname> ## TODO

(3/17/2013 - Only help commands is supported at the moment.)

Command line parameters

You can pass --help to contact for command line parameters.

$ ./contact --help
usage: contact
    --help                Print this list of commands
    --infile <filename>   Read input from file and exit
    --nocolor             Don't use color output
    --noconfig            Don't read ~/.contact.config
    --nosignals           Don't catch the Ctrl-C (INT) signal


To connect to a Riak instance, use the connect command:

connect "host:port";

where host is the host or IP address where an instsance of Riak is running, and port is the protocol buffers port # that Riak is listening on. Check the pb_port setting in app.config for the exact port to use.

To connect to multiple sources:

connect "" as $foo;
connect "" as $bar;

To use a given connection, you can supply an @ suffix on most commands:

using bucket "Foo" fetch "MyKey" @ $foo;

To see a list of connections, use the connections commands:

> connect "" as $foo;
Connecting to Riak @
> connect "" as $bar;
Connecting to Riak @
> connections;

If multiple connections are made, the default connection is undefined at the moment.


To exit the shell, type exit.

Canceling a command

Unless the --nosignals command line paramter is passed to contact, typing Control-C while a command is running will cancel the command. Otherwise, a Control-C will exit the shell normally.


Comments in a script can either be:

/* like this */


// like this


To fetch many objects from a single bucket, you can select a bucket with the use command:

use bucket "Foo";

Otherwise, all commands that require a bucket will need to be prefixed with:

using bucket "Foo" … 

To see the current bucket that you're using:

get bucket;

Use with default options

You can specify default options to use for fetch, store, delete and query2i. Any options you specify in a fetch, store, delete or query2i command will override these defaults. See documentation for corresponding commands for available options.

use bucket "Foo"
        with fetch options r = "1"

use bucket "Foo"
    with fetch options  r = "1"
    and  store options  w = "1", dw="1"
    and  delete options foo = "baz"
    and query2i options foo = "bar";

Fetching Data

To fetch a key named "MyKey" from bucket "Foo", use the following:

using bucket "Foo" fetch "MyKey";

Key and Bucket names are always in double quotes (for now).

To fetch many objects from a single bucket, you can select a bucket with the use command:

use bucket "Foo";
fetch "MyKey";
fetch "MyOtherKey";

To bind a Riak object to a Contact variable:

let myKey = fetch "MyKey";

Once you have a binding ("myKey" in the example above), you can refer to it from other Contact operations. (TODO: not much of a use right now)

Fetching with options

fetch "MyKey" 
    with options 
        r = 1,
        pr = 1;

Available fetch options:

  • r (Integer)
  • pr (Integer)
  • basic_quorum (Boolean)
  • notfound_ok (Boolean)
  • deletedvclock (Boolean)
  • head (Boolean)

Storing Data

To store plain text, json, or xml, you can use the following commands:

/* using "text" will set the content-type to text/plain */  
using bucket "Foo" 
    store "MyKey" 
    with text "This is text";

/* using "json" will set the content-type to application/json */
using bucket "Foo" 
    store "MyKey" 
    with json "{foo:bar}";

/* using "json" will set the content-type to application/xml */
using bucket "Foo" 
    store "MyKey" 
    with xml "<foo>bar</foo>";

/* you can also define your own content type */
store "MyKey" with content-type "text/csv" and "1,2,3,4";

Note, any double quotes appearing in the content string will need to be escaped. To store larger chunks of text, use the scissors delimiter:

// no escaping required!
using bucket "Foo" store "MyKey" with text 
This is "Free form text" and doesn't need any escaping!
// no escaping required!
using bucket "Foo" store "MyKey" with json
    "person": {
        "name": "Dave Parfitt",
        "city": "Buffalo",
        "state": "NY"
// no escaping required!
using bucket "Foo" store "MyKey" with xml
    <subject>This is a reminder</subject>
    <body>Go to the dentist!</body>

Storing with options

using bucket "Foo" 
    store "MyKey" 
        with text "This is text" 
        with options w = 1, pw = 2;

Available store options:

  • w (Integer)
  • pw (Integer)
  • dw (Integer)
  • return_body (Boolean)
  • if_not_modified (Boolean)
  • if_none_match (Boolean)

Storing data with secondary indexes

using bucket "Foo" 
    store "MyKey" 
        with index "twitter_bin" = "test" 
        and index "github_bin" = "test2" 
        and text "This is text";

store "MyKey" 
        with index "twitter_bin" = "test" 
        and index "github_bin" = "test2" 
        and text "This is text";

Deleting objects

using bucket "Foo" delete "MyKey";

delete "MyKey";

delete "MyKey" and options w="1";

Available delete options:

  • r (Integer)
  • w (Integer)
  • pr (Integer)
  • pw (Integer)
  • dw (Integer)
  • **vclock* not implemented at the moment*

Secondary Index Query

Query names and parameters must always appear in double quotes.

Setup sample data with these commands:

using bucket "Foo" 
store "First" 
with index "range_int" = "1" 
and text "This is text 1";

using bucket "Foo" 
store "Last" 
with index "range_int" = "2" 
and text "This is text 2";

Execute queries like this:

using bucket "Foo" query2i with index "range_int" and value "1";

or with use bucket:

use bucket "Foo";
query2i with index "range_int" and value "2";
query2i with index "range_int" from "1" to "2";

Secondary Index Query with Fetch

To fetch the results of all keys as the result of a 2i query, use the query2i and fetch command:

query2i and fetch with index "year_int" and value "2010";

See Contact Sample Data for an example 2i query with custom rendered JSON output.

Bucket Properties

To get a map of bucket properties, use:

using bucket "Foo" get properties;


use bucket "Foo";
get properties;
> using bucket "Foo" get properties;

{dw=null, basic_quorum=null, not_found_ok=null, small_vclock=null, young_vclock=null, w=null, backend=null, r=null, search=null, allow_siblings=false, name=Foo, last_write_wins=null, post_commit_hooks=[], n_val=3, pw=null, pre_commit_hooks=[], old_vclock=null, rw=null, pr=null}

To set bucket properties:

use bucket "Foo";
set properties n_val=2, allow_siblings=false;

At the moment, there are only 2 properties available via the Protocol Buffers interface:

  • allow_siblings (Boolean)
  • n_val (Integer)

All other properties coming soon to a theater near you.

Listing Buckets

Listing buckets should NOT be used on any production system

list buckets;

Listing Keys

Listing keys should NOT be used on any production system

using bucket "Foo" list keys;


use bucket "Foo";
list keys;

Counting Keys in a Bucket

using bucket "Foo" count keys;


use bucket "Foo";
count keys;


> using bucket "Google" count keys;
Counting keys for Google...
Bucket Google contains 1438 keys

Resolving conflicts

The default conflict resolver for Contact will pick a random sibling upon conflict detection. To change this behavior, you can specify you own resolver with Javascript:

use bucket "MyBucket" with resolver javascript ~%~
function(siblings) {
        if(siblings.size() > 1) {
          return siblings.toArray()[0];
        } else if(siblings.size() == 1) {
          out.println("no siblings");
          return siblings.iterator().next();
        } else {
           return null;

set properties allow_siblings=true;

store "Foo" with text "1000";
store "Foo" with text "2000";

Sample Data

See the Contact Sample Data repository for sample data that can be easily imported.

Customizable Actions and Output

Contact actions and output are customizable via the embedded Mozilla Rhino Javascript interpreter. Java objects are exposed as Javascript objects, and you have the ability to modify command parameters and output on the fly. Most actions come in pairs of pre/postcommand.

Here's an example of the default action for rendering the results of a fetch:

set action postfetch with javascript 
  if(riak_object != undefined) { println(riak_object.getValueAsString()); }

To see the code for an action:

get action postfetch;

For example, to print out the last modified date:

set action postfetch with javascript 
  if(riak_object != undefined) { println(riak_object.getLastModified()); }

Processing JSON

Here's a more in depth example that renderes sections of a JSON doc:

use bucket "Foo";

store "JsonTest1" with json
    "firstName": "John",
    "lastName": "Smith",
    "age": 25,
    "address": {
        "streetAddress": "21 2nd Street",
        "city": "New York",
        "state": "NY",
        "postalCode": 10021

store "JsonTest2" with json
    "firstName": "Dave",
    "lastName": "Parfitt",
    "age": 99,
    "address": {
        "streetAddress": "1000 Big Nosk drive",
        "city": "Buffalo",
        "state": "NY",
        "postalCode": 14222

set action postfetch with javascript 
if(riak_object != undefined) { 
    var v = riak_object.getValueAsString(); 
    var j = JSON.parse(v);
    println(j.firstName + " " + j.lastName);
    println("   " + j.address.streetAddress);
    println("   " + +
                    ", " + j.address.state +
                    " " + j.address.postalCode);

fetch "JsonTest1";
fetch "JsonTest2";

displays output that looks like this:

John Smith
   21 2nd Street
   New York, NY 10021

Dave Parfitt
   1000 Big Nosk drive
   Buffalo, NY 14222

The key function in the postfetch action above is JSON.parse(v), which turns evaluates a string and returns a Javascript object.

Processing XML

Mozilla Rhino comes with E4X embedded, so you can make scripts such as:

use bucket "Users";

store "XMLTest1" with xml
        <line1>21 2nd Street</line1>
        <line2>Apt 3k</line2>
        <state>New York</state>
        <line1>21 3nd Street</line1>
        <line2>Apt 3d</line2>
        <state>New York</state>

set action postfetch with javascript 
if(riak_object != undefined) {
    var v = riak_object.getValueAsString();
    var users = new XML(v)

fetch "XMLTest1";

Available actions

All scripts have out and err available to them for writing.

In addition, the 2 following convenience functions are setup for you:

var print = function(s) { out.print(s); };
var println = function(s) { out.println(s); };

Loading Scripts

To load an entire script file, simply execute the load script command:

    load script "filename.js";

To execute arbitrary Javascript:

    script "println('hello world');";

    // OR

    script ~%~
        println("hello world!");

Batch mode

Pass in the --infile <filename> parameter to contact to process a file containing Contact commands. Contact will exit upon completion.


If you want to run some code upon startup, you can create a file called ~/.contact.config with any Contact code you want.

For example, if you always connect to the same host, you can add this to the .contact.config file:

connect "";

Basic Types

  • Strings: "This is a string"
  • Integers: 1000
  • Floats: Not implemented
  • Boolean: false, true
  • Here documents
Any text between the "scissor delimeters" most likely won't need to be escaped. 
This means you can paste a full XML or JSON document here, and you don't 
have to worry about escaping quotes! Of course, you'll need to escape the scissor delimiter with: \~%~


  • Riak admin commands
  • runtime config changes of a Riak node
  • per bucket actions, action cleanup
  • platform support/testing on Linux + Windows
  • connection settings/pooling/grouping
  • conflict resolution needs some cleanup
  • link walking
  • user meta for store
  • general code cleanup
  • MR -> probably not going to address, as whatever I come up with will probably kill your cluster.
  • Riak Search (Yokozuna integration)
  • Fix tab completion
    • pasting text into the shell erroneously kicks off tab completion


  • v1: data io, basic admin, maybe search

  • v1.x: expressions


If you are a Riak + Java fan, I'm looking for devs to help out.

Fork this repo, create a feature branch using something like this:

git checkout -b branch_name

and submit a pull request.

Please send me an email (dparfitt at basho dot com) and let me know if you want to work on any features.

Only friendly pull requests accepted.


© 2014 Dave Parfitt

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