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diff --git a/posts/2009-12-13-riak-perl-and-kiokudb.md b/posts/2009-12-13-riak-perl-and-kiokudb.md deleted file mode 100644 index cc39500..0000000 --- a/posts/2009-12-13-riak-perl-and-kiokudb.md +++ /dev/null @@ -1,147 +0,0 @@ -As I was looking for a system to store documents at <a href="http://linkfluence.net">$work</a>, <a href="http://www.basho.com/Riak.html">Riak</a> was pointed to me by one of my coworkers. I'm looking for a solution of this type to store various types of documents, from HTML pages to json. I need a system that is distributed, faul tolerant, and that works with Perl. - -So Riak is a document based database, it's key value, no sql, REST, and in Erlang. You can read more about it <a href="http://riak.basho.com/nyc-nosql/">here</a> or watch an introduction <a href="http://vimeo.com/6973519">here</a>. Like <ahref="http://couchdb.apache.org/">CouchDB</a>, Riak provides a REST interface, so you don't have to write any Erlang code. - -One of the nice things with Riak it's that it let you defined the N, R and W value for each operation. This values are: - -* N: the number of replicas of each value to store -* R: the number of replicas required to perform a read operation -* W: the number of replicas needed for a write operation - -Riak comes with library for python ruby PHP and even javascript, but not for Perl. As all these libraries are just communicating with Riak via the REST interface, I've <a href="http://git.lumberjaph.net/p5-anyevent-riak.git/">started to write one</a> using AnyEvent::HTTP, and <a href="http://git.lumberjaph.net/p5-kiokudb-backend-riak.git/">also a backend for KiokuDB</a>. - -## Installing and using Riak - -If you interested in Riak, you can install it easily. First, you will need the Erlang VM. On debian, a simple - -```bash -% sudo aptitude install erlang -``` - -install everything you need. Next step is to install Riak: - -```bash -% wget http://hg.basho.com/riak/get/riak-0.6.2.tar.gz -% tar xzf riak-0.6.2.tar.gz -% cd riak -% make -% export RIAK=`pwd` -``` - -Now, you can start to use it with - -```bash -% ./start-fresh config/riak-demo.erlenv -``` - -or if you want to test it in cluster mode, you can write a configuration like this: - -```erlang - {cluster_name, "default"}. - {ring_state_dir, "priv/ringstate"}. - {ring_creation_size, 16}. - {gossip_interval, 60000}. - {storage_backend, riak_fs_backend}. - {riak_fs_backend_root, "/opt/data/riak/"}. - {riak_cookie, riak_demo_cookie}. - {riak_heart_command, "(cd $RIAK; ./start-restart.sh $RIAK/config/riak-demo.erlenv)"}. - {riak_nodename, riakdemo}. - {riak_hostname, "192.168.0.11"}. - {riak_web_ip, "192.168.0.11"}. - {riak_web_port, 8098}. - {jiak_name, "jiak"}. - {riak_web_logdir, "/tmp/riak_log"}. -``` - -Copy this config on a second server, edit it to replace the riak\_hostname and riak\_nodename. On the first server, start it like show previously, then on the second, with - -```bash -% ./start-join.sh config/riak-demo.erlenv 192.168.0.11 -``` - -where the IP address it the address of the first node in your cluster. - -Let's check if everything works: - -```bash -% curl -X PUT -H "Content-type: application/json" \ - http://192.168.0.11:8098/jiak/blog/lumberjaph/ \ - -d "{\"bucket\":\"blog\",\"key\":\"lumberjaph\",\"object\":{\"title\":\"I'm a lumberjaph, and I'm ok\"},\"links\":[]}" - -% curl -i http://192.168.0.11:8098/jiak/blog/lumberjaph/ -``` - -will output (with the HTTP blabla) - -```javascript - {"object":{"title":"I'm a lumberjaph, and I'm ok"},"vclock":"a85hYGBgzGDKBVIsbGubKzKYEhnzWBlCTs08wpcFAA==","lastmod":"Sun, 13 Dec 2009 20:28:04 GMT","vtag":"5YSzQ7sEdI3lABkEUFcgXy","bucket":"blog","key":"lumberjaph","links":[]} -``` - -## Using Riak with Perl and KiokuDB - -I need to store various things in Riak: html pages, json data, and objects using KiokuDB. I've started to write a client for Riak with AnyEvent, so I can do simple operations at the moment, (listing information about a bucket, defining a new bucket with a specific schema, storing, retriving and deleting documents). To create a client, you need to - -```perl -my $client = AnyEvent::Riak->new( - host => 'http://127.0.0.1:8098', - path => 'jiak', -); -``` - -As Riak exposes to you it's N, R, and W value, you can also set them in creation the client: - -```perl -my $client = AnyEvent::Riak->new( - host => 'http://127.0.0.1:8098', - path => 'jiak', - r => 2, - w => 2, - dw => 2, -); -``` - -where: - -* the W and DW values define that the request returns as soon as at least W nodes have received the request, and at least DW nodes have stored it in their storage backend. -* with the R value, the request returns as soon as R nodes have responded with a value or an error. You can also set this values when calling fetch, store and delete. By default, the value is set to 2. - -So, if you wan to store a value, retrieve it, then delete it, you can do: - -```perl -my $store = - $client->store({bucket => 'foo', key => 'bar', object => {baz => 1},}) - ->recv; -my $fetch = $client->fetch('foo', 'bar')->recv; -my $delete = $client->delete('foo', 'bar')->recv; -``` - -If there is an error, the croak method from AnyEvent is used, so you may prefer to do this: - -```perl -use Try::Tiny; -try { - my $fetch = $client->fetch('foo', 'baz')->recv; -} -catch { - my $err = decode_json $_; - say "error: code => " . $err->[0] . " reason => " . $err->[1]; -}; -``` - -The error contains an array, with the first value the HTTP code, and the second value the reason of the error given by Riak. - -At the moment, the KiokuDB backend is not complete, but if you want to start to play with is, all you need to do is: - -```perl -my $dir = KiokuDB->new( - backend => KiokuDB::Backend::Riak->new( - db => AnyEvent::Riak->new( - host => 'http://localhost:8098', - path => 'jiak', - ), - bucket => 'kiokudb', - ), -); - -$dir->txn_do(sub { $dir->insert($key => $object) }); -``` |