#Oknok Datastore Loader
Oknok uses a configuration file to load a set of persistent data stores.
TODOs: Update dependencies in gemspec
#file: /path/to/config/file/config_file_name.yaml
avail_stores: #top level key
iris: #user defined id for this data store
type: couchdb #defined by oknok
host: couchsurfer.iriscouch.com #location of data store
user: ~ #specific user data required (i.e., username/password)
require 'oknok'
stores = Oknok::StoreTracker.new("/path/to/config/file/config_file_name.yaml")
store = stores.first #we only had one store for this example
store.store_handle #=> CouchRest::Database object
Each oknok store will have a status associated with it, that will indicate whether the store was successfully connected or not.
#successful connection
store.status_obj
#=> Oknok::StoreAccess::Access object
#unsuccessful connection
store.store_handle
#=> nil
store_status_obj
#=> Oknok::StoreAccess::NotFound object
Connection Status Objects:
Oknok::StoreAccess::Access - Store was successfully accessed
Oknok::StoreAccess::AccessDenied - The data store application denied access for some reason
Oknok::StoreAccess::Unavailable - The data store application didn't respond
Oknok::StoreAccess::NotFound - The data store application couldn't find the data store specified
Oknok::StoreAccess::Undefined - Unable to determine the type of data store
Important Note: Exceptions relating to connection failures are rescued and mapped to the appropriate connection status. This means you don't need all of your data stores to be available concurrently.
Of course, this is overkill for accessing a single data store, what it's really intended for is to provide access to multiple data stores regardless of the type of store.
#file: /path/to/config/file/config_file_name.yaml
avail_stores:
iris:
type: couchdb
host: couchsurfer.iriscouch.com
user: ~
local_filesystem1:
type: file
host: /tmp/spec1/
user: ~
remote_mysql:
type: mysql
host_lookup_engine: WebService
host: 'http://couchsurfer.iriscouch.com/ec2lookup/open_db'
init_db: oknok
user: open:open
require 'oknok'
stores = Oknok::StoreTracker.new("/path/to/config/file/config_file_name.yaml")
iris = stores.get_store_name("iris")
iris_handle = iris.store_handle
#=> CouchRest::Database Object
local_filesys = stores.get_store_name("local_filesystem1")
local_handle = local_filesys.store_handle
#=> "/tmp/spec1/"
Oknok allows for host names to be computed in addition to being specified. In this particular example the
host name defined by the parameter host is actually a web server that takes the name of the store ('remote_mysql')
and returns the IP address of the actual host with the remote mysql service running. The way you get access to
the store is exactly the same though:
mysql= stores.get_store_name("remote_mysql")
mysql_handle = mysql.store_handle
#=> DBI::DBD::MysqlHandle
#file: /path/to/config/file/config_file_name.yaml
avail_stores:
local_filesystem1:
type: file
host: /tmp/spec1/
user: ~
local_filesystem2:
type: file
host: /tmp/spec2/
user: ~
It's ok to have multiple stores of the same type.
require 'oknok'
stores = Oknok::StoreTracker.new("/path/to/config/file/config_file_name.yaml")
file_stores = stores.get_store_types("file")
file_stores.map {|sto| sto.store_handle}
#=> ["/tmp/spec1", "/tmp/spec2"]