fwissr

fwissr-python is a registry configuration tool, compatible with fwissr, its ruby counterpart. Made by fotonauts.

• Free software: MIT license
• Documentation: http://fwissr.rtfd.org.

Install

$ [sudo] pip install fwissr

Usage

Create the main fwissr.json configuration file in either /etc/fwissr/ or ~/.fwissr/ directory:

{
  "foo" : "bar",
  "horn" : { "loud" : true, "sounds": [ "TUuuUuuuu", "tiiiiiiIIiii" ] }
}

In your application, you can access fwissr's global registry that way:

from fwissr.fwissr import Fwissr
Fwissr['/foo']
# u'bar'
Fwissr['/horn']
# {u'sounds': [u'TUuuUuuuu', u'tiiiiiiIIiii'], u'loud': True}
Fwissr['/horn/loud']
# True
Fwissr['/horn/sounds']
# [u'TUuuUuuuu', u'tiiiiiiIIiii']

In bash you can call the fwissr tool:

$ fwissr /foo
bar

# json output
$ fwissr -j /horn
{"loud": true, "sounds": ["TUuuUuuuu", "tiiiiiiIIiii"]}

# pretty print json output
$ fwissr -j -p /horn
{
    "loud": true,
    "sounds": [
        "TUuuUuuuu",
        "tiiiiiiIIiii"
    ]
}

# dump all registry with pretty print json output
# NOTE: yes, that's the same as 'fwissr -jp /'
$ fwissr --dump -jp
{
  "horn": {
    "loud": true,
    "sound": [
      "TUuuUuuuu",
      "tiiiiiiIIiii"
    ]
  }
}

Additional configuration file

Provide additional configuration files with the fwissr_sources setting in fwissr.json:

{
  "fwissr_sources": [
    { "filepath": "/etc/my_app.json" }
  ]
}

The settings for that configuration will be prefixed with the file name.

For example, with that /etc/my_app.json:

{ "foo": "bar", "bar": "baz" }

the settings can be accessed that way:

from fwissr.fwissr import Fwissr

Fwissr['/my_app']
#=> { "foo": "bar", "bar": "baz" }

Fwissr['/my_app/foo']
#=> "bar"

Fwissr['/my_app/bar']
#=> "baz"

You can bypass that behaviour with the top_level setting:

{
  "fwissr_sources": [
    { "filepath": "/etc/my_app.json", "top_level": true }
  ]
}

With the top_level setting activated the configuration settings are added to registry root:

from fwissr.fwissr import Fwissr

Fwissr['/']
#=> { "foo": "bar", "bar": "baz" }

Fwissr['/foo']
#=> "bar"

Fwissr['/bar']
#=> "baz"

Note that you can provide .json and .yaml configuration files.

Directory of configuration files

If the filepath setting is a directory, then all .json and .yaml files in that directory (but NOT in subdirectories) will be imported in the global registry:

{
  "fwissr_sources": [
    { "filepath": "/mnt/my_app/conf/" },
  ],
}

With /mnt/my_app/conf/database.yaml:

production:
  adapter: mysql2
  encoding: utf8
  database: my_app_db
  username: my_app_user
  password: my_app_pass
  host: db.my_app.com

and /mnt/my_app/conf/credentials.json:

{ "key": "i5qw64816c", "code": "448e4wef161" }

the settings can be accessed that way:

from fwissr.fwissr import Fwissr

Fwissr['/database']
#=> { "production": { "adapter": "mysql2", "encoding": "utf8", "database": "my_app_db", "username": "my_app_user", "password": "my_app_pass", "host": "db.my_app.com" } }

Fwissr['/database/production/host']
#=> "db.my_app.com"

Fwissr['/credentials']
#=> { "key": "i5qw64816c", "code": "448e4wef161" }

Fwissr['/credentials/key']
#=> "i5qw64816c"

File name mapping to setting path

Use dots in file name to define a path for configuration settings.

For example:

{
  "fwissr_sources": [
    { "filepath": "/etc/my_app.database.slave.json" }
  ]
}

with that /etc/my_app.database.slave.json:

{ "host": "db.my_app.com", "port": "1337" }

The settings can be accessed that way:

from fwissr.fwissr import Fwissr

Fwissr['/my_app/database/slave/host']
#=> "db.my_app.com"

Fwissr['/my_app/database/slave/port']
#=> "1337"

Mongodb source

You can define a mongob collection as a configuration source:

{
  "fwissr_sources": [
    { "mongodb": "mongodb://db1.example.net/my_app", "collection": "config" }
  ]
}

Each document in the collection is a setting for that configuration.

The _id document field is the setting key, and the value document field is the setting value.

For example:

> db["my_app.stuff"].find()
{ "_id" : "foo", "value" : "bar" }
{ "_id" : "database", "value" : { "host": "db.my_app.com", "port": "1337" } }

from fwissr.fwissr import Fwissr

Fwissr['/my_app/stuff/foo']
#=> "bar"

Fwissr['/my_app/stuff/database']
#=> { "host": "db.my_app.com", "port": "1337" }

Fwissr['/my_app/stuff/database/port']
#=> "1337"

As with configuration files you can use dots in collection name to define a path for configuration settings. The top_level setting is also supported to bypass that behaviour. Note too that the fwissr collection is by default a top_level configuration (as the /etc/fwissr/fwissr.json configuration file).

Refreshing registry

Enable registry auto-update with the refresh source setting.

For example:

{
  "fwissr_sources": [
    { "filepath": "/etc/my_app/my_app.json" },
    { "filepath": "/etc/my_app/stuff.json", "refresh": true },
    { "mongodb": "mongodb://db1.example.net/my_app", "collection": "production" },
    { "mongodb": "mongodb://db1.example.net/my_app", "collection": "config", "refresh": true }
  ]
}

The /etc/my_app/my_app.json configuration file and the production mongodb collection are read only once, whereas the settings holded by the /etc/my_app/stuff.json configuration file and the config mongodb collection are expired periodically and re-fetched.

The default freshness is 30 seconds, but you can change it with the fwissr_refresh_period setting:

{
  "fwissr_sources": [
    { "filepath": "/etc/my_app/my_app.json" },
    { "filepath": "/etc/my_app/stuff.json", "refresh": true },
    { "mongodb": "mongodb://db1.example.net/my_app", "collection": "production" },
    { "mongodb": "mongodb://db1.example.net/my_app", "collection": "config", "refresh": true }
   ],
  "fwissr_refresh_period": 60
}

The refresh is done periodically in a thread:

from fwissr.fwissr import Fwissr
import time

Fwissr['/stuff/foo']
#=> "bar"

# > Change '/etc/my_app/stuff.json' file by setting: {"foo":"baz"}

# Wait 2 minutes
time.sleep(120)

# The new value is now in the registry
Fwissr['/stuff/foo']
#=> "baz"

Create a custom registry

fwissr is intended to be easy to setup: just create a configuration file and that configuration is accessible via the global registry. But if you need to, you can create your own custom registry:

from fwissr.fwissr import Fwissr
from fwissr.registry import Registry
from fwissr.source.source import Source
# create a custom registry
registry = Registry(refresh_period=20)

# add configuration sources to registry
registry.add_source(Source.from_settings({ 'filepath': '/etc/my_app/my_app.json' }))
registry.add_source(Source.from_settings({ 'filepath': '/etc/my_app/stuff.json', 'refresh': true }))
registry.add_source(Source.from_settings({ 'mongodb': 'mongodb://db1.example.net/my_app', 'collection': 'production' }))
registry.add_source(Source.from_settings({ 'mongodb': 'mongodb://db1.example.net/my_app', 'collection': 'config', 'refresh': True }))

registry['/stuff/foo']
#=> 'bar'

Create a custom source

Currently fwissr.source.file.File and fwissr.source.mongodb.Mongodb are the two kinds of possible registry sources, but you can define your own source:

TODO

Credits

The Fotonauts team: http://www.fotopedia.com

Copyright (c) 2013 Fotonauts released under the MIT license.