Class: CMDB::Source::File

Inherits:
CMDB::Source show all
Defined in:
lib/cmdb/source/file.rb

Overview

Data source that is backed by a YAML/JSON file that lives in the filesystem. The name of the file becomes the top-level key under which all values in the file are exposed, preserving their exact structure as parsed by YAML/JSON.

Examples:

Use my.yml as a CMDB source

source = Source::File.new('/tmp/my.yml') # contains a top-level stanza named "database"
source['my']['database']['host'] # => 'db1-1.example.com'

Instance Attribute Summary

Attributes inherited from CMDB::Source

#prefix, #uri

Instance Method Summary collapse

Methods inherited from CMDB::Source

create, detect

Constructor Details

#initialize(uri, prefix) ⇒ File

Read a data file whose location is specified by a file:// URI.

Parameters:

  • uri (URI) —

    logical description of this source

  • prefix (String) —

    unique dot-notation prefix of all this source’s keys, if any

Raises:

  • (BadData) —

    if the file’s content is malformed



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# File 'lib/cmdb/source/file.rb', line 18

def initialize(uri, prefix)
  super(uri, prefix)
  path = @uri.path
  filename  = ::File.basename(path)
  extension = ::File.extname(filename)
  raw_bytes = ::File.read(path)
  raw_data  = nil

  begin
    case extension
    when /jso?n?$/i
      raw_data = JSON.load(raw_bytes)
    when /ya?ml$/i
      raw_data = YAML.load(raw_bytes)
    else
      raise BadData.new(@uri, 'file with unknown extension; expected js(on) or y(a)ml')
    end
  rescue StandardError
    raise BadData.new(@uri, 'CMDB data file')
  end

  @data = {}
  flatten(raw_data, @prefix, @data)

  # File sources are static; we can check them for data errors at load
  # time. Do this by each'ing, which validates values as a side effect.
  each_pair { |_,_| }
end

Instance Method Details

#each_pair {|key, value| ... } ⇒ Object

Enumerate the keys and values in this source.

Yields:

  • every key/value in the source

Yield Parameters:

  • key (String)
  • value (Object) 


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# File 'lib/cmdb/source/file.rb', line 60

def each_pair(&_block)
  @data.each_pair do |key, value|
    validate!(key, value)
    yield(key, value)
  end
end

#get(key) ⇒ Object

Get the value of key.

Returns:

  • (Object) —

    the key’s value, or nil if not found



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# File 'lib/cmdb/source/file.rb', line 50

def get(key)
  value = @data[key]
  validate!(key, value)
end