Class: Gin::Config

Inherits:
Object
  • Object
show all
Defined in:
lib/gin/config.rb

Overview

Environment-specific config files loading mechanism.

# config_dir/memcache.yml
default: &default
  host: http://memcache.example.com
  connections: 5

development: &dev
  host: localhost:123321
  connections: 1

test: *dev

staging:
  host: http://stage-memcache.example.com

production: *default

# config.rb
config = Gin::Config.new 'staging', :dir => 'config/dir'

config['memcache.host']
#=> "http://stage-memcache.example.com"

config['memcache.connections']
#=> 5

Config files get loaded on demand. They may also be reloaded on demand by setting the :ttl option to expire values. Values are only expired for configs with a source file whose mtime value differs from the one it had at its previous load time.

# 5 minute expiration
config = Gin::Config.new 'staging', :ttl => 300

Constant Summary collapse

SYNTAX_ERROR = 
defined?(Psych) ? Psych::SyntaxError : ArgumentError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(environment, opts = {}) ⇒ Config

Create a new config instance for the given environment name. The environment dictates which part of the config files gets exposed.



50
51
52
53
54
55
56
57
58
59
60
61
 
# File 'lib/gin/config.rb', line 50

def initialize environment, opts={}
  @environment = environment
  @logger      = opts[:logger] || Logger.new($stdout)
  @ttl         = opts[:ttl]    || false
  @dir         = opts[:dir]    || "./config"

  @data       = {}
  @load_times = {}
  @mtimes     = {}

  @lock = Gin::RWLock.new(opts[:write_timeout])
end

Instance Attribute Details

#dir ⇒ Object

Returns the value of attribute dir.



42
43
44
 
# File 'lib/gin/config.rb', line 42

def dir
  @dir
end

#environment ⇒ Object

Returns the value of attribute environment.



42
43
44
 
# File 'lib/gin/config.rb', line 42

def environment
  @environment
end

#logger ⇒ Object

Returns the value of attribute logger.



42
43
44
 
# File 'lib/gin/config.rb', line 42

def logger
  @logger
end

#ttl ⇒ Object

Returns the value of attribute ttl.



42
43
44
 
# File 'lib/gin/config.rb', line 42

def ttl
  @ttl
end

Instance Method Details

#[](key) ⇒ Object

Non-raising config lookup. The following query the same value:

# Raises an error if the 'user' key is missing.
config.get('remote_shell')['user']['name']

# Doesn't raise an error if a key is missing.
# Doesn't support configs with '.' in the key names.
config['remote_shell.user.name']



185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
 
# File 'lib/gin/config.rb', line 185

def [] key
  chain = key.to_s.split(".")
  name = chain.shift
  curr = get(name, true)
  return unless curr

  chain.each do |k|
    return unless Array === curr || Hash === curr
    val = curr[k]
    val = curr[k.to_i] if val.nil? && k.to_i.to_s == k
    curr = val
  end

  curr
end

#current?(name) ⇒ Boolean

Checks if the given config is outdated.

Returns:

  • (Boolean) 


156
157
158
159
160
161
162
 
# File 'lib/gin/config.rb', line 156

def current? name
  @lock.read_sync do
    @ttl == false && @data.has_key?(name) ||
      !@load_times[name] && @data.has_key?(name) ||
      @load_times[name] && Time.now - @load_times[name] <= @ttl
  end
end

#get(name, safe = false) ⇒ Object

Get a config value from its name. Setting safe to true will return nil instead of raising errors. Reloads the config if reloading is enabled and value expired.



145
146
147
148
149
150
 
# File 'lib/gin/config.rb', line 145

def get name, safe=false
  return @lock.read_sync{ @data[name] } if
    current?(name) || safe && !File.file?(filepath_for(name))

  load_config(name) || @lock.read_sync{ @data[name] }
end

#has?(name) ⇒ Boolean

Checks if a config exists in memory or on disk, by its name.

# If foo config isn't loaded, looks for file under @dir/foo.yml
config.has? 'foo'
#=> true

Returns:

  • (Boolean) 


171
172
173
 
# File 'lib/gin/config.rb', line 171

def has? name
  @lock.read_sync{ @data.has_key?(name) } || File.file?(filepath_for(name))
end

#load! ⇒ Object

Force-load all the config files in the config directory.



77
78
79
80
81
82
83
 
# File 'lib/gin/config.rb', line 77

def load!
  return unless @dir
  Dir[File.join(@dir, "*.yml")].each do |filepath|
    load_config filepath
  end
  self
end

#load_config(name) ⇒ Object

Load the given config name, or filename.

# Loads @dir/my_config.yml
config.load_config 'my_config'
config['my_config']
#=> data from file

# Loads the given file if it exists.
config.load_config 'path/to/my_config.yml'
config['my_config']
#=> data from file



98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
 
# File 'lib/gin/config.rb', line 98

def load_config name
  name = name.to_s

  if File.file?(name)
    filepath = name
    name = File.basename(filepath, ".yml")
  else
    filepath = filepath_for(name)
  end

  raise Gin::MissingConfig, "No config file at #{filepath}" unless
    File.file?(filepath)

  @lock.write_sync do
    @load_times[name] = Time.now

    mtime = File.mtime(filepath)
    return if mtime == @mtimes[name]

    @mtimes[name] = mtime

    c = YAML.load_file(filepath)
    c = (c['default'] || {}).merge(c[@environment] || {})

    @data[name] = c
  end

rescue SYNTAX_ERROR
  @logger.write "[ERROR] Could not parse config `#{filepath}' as YAML"
  return nil
end

#set(name, data) ⇒ Object

Sets a new config name and value. Configs set in this manner do not qualify for reloading as they don’t have a source file.



135
136
137
 
# File 'lib/gin/config.rb', line 135

def set name, data
  @lock.write_sync{ @data[name] = data }
end

#write_timeout(sec = nil) ⇒ Object

Get or set the write timeout when waiting for reader thread locks. Defaults to 0.05 sec. See Gin::RWLock for more details.



68
69
70
71
 
# File 'lib/gin/config.rb', line 68

def write_timeout sec=nil
  @lock.write_timeout = sec if sec
  @lock.write_timeout
end