Riak Intro at Munich Node.js
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This document discusses using Riak, a distributed key-value database, with Node.js. Riak uses HTTP as its interface and can store JSON data, making it a good fit for Node.js applications. The Riak client library for Node.js allows storing, retrieving, and querying data from Riak directly in JavaScript code. MapReduce queries in Riak can be used to process large datasets in parallel across the distributed cluster, and custom map and reduce functions can be defined in JavaScript.
![or MapReduce
curl -XPOST http://localhost:8098/mapred
-H 'Content-Type: application/json'
-d '{ "inputs":"training",
"query":[{"map":{"language":"javascript",
"source":"function(riakObject) {
var val = riakObject.values[0].data.match(/pizza/g);
return [[riakObject.key, (val ? val.length : 0)]];
}"}}]}'](https://image.slidesharecdn.com/mnugoctober2013-131014141229-phpapp01/85/Riak-Intro-at-Munich-Node-js-25-320.jpg)
![var key_filter = [["tokenize", "_", 1],
["to_lower"],
["matches", "foo"]]
db.mapreduce.add({ bucket: "foos", key_filters: key_filter })](https://image.slidesharecdn.com/mnugoctober2013-131014141229-phpapp01/85/Riak-Intro-at-Munich-Node-js-37-320.jpg)
![Map custom function
var func = function(v, _keyData, arg) {
var v = Riak.mapValuesJson(v)[0];
(v.val === "foo") ? return [v] : return [];
}
db.mapreduce.add("foos").map(func).run()](https://image.slidesharecdn.com/mnugoctober2013-131014141229-phpapp01/85/Riak-Intro-at-Munich-Node-js-39-320.jpg)
![Reduce with custom
var func = function(values) {
return [ values.length ]
}
db.mapreduce...
.reduce(func)
.run()](https://image.slidesharecdn.com/mnugoctober2013-131014141229-phpapp01/85/Riak-Intro-at-Munich-Node-js-40-320.jpg)
![A little more complex
function(values) {
return values.reduce(function(acc, v) {
if(v.bar) {
var curr = acc["bar"] || 0
acc["bar"] = curr + 1
}
return acc;
})
}](https://image.slidesharecdn.com/mnugoctober2013-131014141229-phpapp01/85/Riak-Intro-at-Munich-Node-js-41-320.jpg)
Riak Intro at Munich Node.js
- 1. Riak and Node.js: Best served with HTTP Philipp Fehre https://github.com/sideshowcoder
- 3. What is Riak? A Key Value store A Dynamo store!
- 4. Distributed
- 7. Replicated
- 13. Scaling Basically means add more machines
- 14. Gains more storage more throughput lower latency
- 15. And it is Web friendly HTTP Interface Value is irrelevant so you can store JSON Support for JavaScript functions
- 16. When to use Riak
- 18. Data Organization keys identify objects objects have metadata objects are grouped into buckets
- 19. More Data Features Links Secoundary indexes Timeouts
- 20. HTTP Riak understands simple HTTP
- 21. Create some data curl -v -XPUT http://localhost:8098/riak/test/doc -H "Content-Type: application/json" -d '{"bar":"baz"}'
- 22. Query by key curl -v http://localhost:8098/riak/test/doc
- 23. Everything can be done via HTTP
- 24. like setting properties of the bucket curl -v -XPUT -H "Content-Type: application/json" -d '{"props":{"n_val":5}}'
- 25. or MapReduce curl -XPOST http://localhost:8098/mapred -H 'Content-Type: application/json' -d '{ "inputs":"training", "query":[{"map":{"language":"javascript", "source":"function(riakObject) { var val = riakObject.values[0].data.match(/pizza/g); return [[riakObject.key, (val ? val.length : 0)]]; }"}}]}'
- 26. Ok but we do JavaScript
- 27. ... or more like Node
- 28. Using Riak from Node
- 29. JavaScript all the way down if you want it to be!
- 30. The Client var db = require("riak-js").getClient()
- 31. Store an Object var obj = { val: "foo", bar: true } db.save("foos", "foo_1", obj, {}, function(err) { if(!err) console.log("stored") })
- 32. Retrieve an Object db.get("foos", "foo_1", function(err, data, meta) { if(!err) { console.log(data) console.log(meta) } })
- 33. Map and Reduce "MapReduce is a programming model for processing large data sets with a parallel, distributed algorithm on a cluster" -Wikipedia
- 35. Riak MapReduce Queries provide a set of keys provide a map function provide a reduce function
- 37. var key_filter = [["tokenize", "_", 1], ["to_lower"], ["matches", "foo"]] db.mapreduce.add({ bucket: "foos", key_filters: key_filter })
- 38. Map a buildin db.mapreduce .add("foos") .map({ name: 'Riak.mapValueJson', keep: true }) .run()
- 39. Map custom function var func = function(v, _keyData, arg) { var v = Riak.mapValuesJson(v)[0]; (v.val === "foo") ? return [v] : return []; } db.mapreduce.add("foos").map(func).run()
- 40. Reduce with custom var func = function(values) { return [ values.length ] } db.mapreduce... .reduce(func) .run()
- 41. A little more complex function(values) { return values.reduce(function(acc, v) { if(v.bar) { var curr = acc["bar"] || 0 acc["bar"] = curr + 1 } return acc; }) }
- 42. Questions · Usergroup: www.meetup.com/Riak-Munchen/ · More on the basics: littleriakbook.com