Class: Labkit::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/labkit/context.rb

Overview

A context can be used to provide structured information on what resources GitLab is working on within a service.

Values can be provided by passing a hash. If one of the values is a Proc the proc will only be called when the value is actually needed.

Multiple contexts can be nested, the nested context will inherit the values from the closest outer one. All contexts will have the same correlation id.

Usage:

Labkit::Context.with_context(user: 'username', root_namespace: -> { get_root_namespace } do |context|
  logger.info(context.to_h)
end

Constant Summary collapse

LOG_KEY = 
"meta"
CORRELATION_ID_KEY = 
"correlation_id"
RAW_KEYS = 
[CORRELATION_ID_KEY].freeze
HEADER_PREFIX = 
"X-Gitlab-"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(values = {}) ⇒ Context

Returns a new instance of Context.



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# File 'lib/labkit/context.rb', line 85

def initialize(values = {})
  @data = {}

  assign_attributes(values)
end

Class Method Details

.correlation_id ⇒ Object 



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# File 'lib/labkit/context.rb', line 54

def correlation_id
  contexts.last&.correlation_id
end

.current ⇒ Object 



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# File 'lib/labkit/context.rb', line 58

def current
  contexts.last
end

.header_name(name) ⇒ Object 



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# File 'lib/labkit/context.rb', line 74

def header_name(name)
  HEADER_PREFIX + log_key(name).titlecase(keep_id_suffix: true).gsub(/\W/, "-")
end

.known_log_keys ⇒ Object 



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# File 'lib/labkit/context.rb', line 70

def known_log_keys
  @known_log_keys ||= (KNOWN_KEYS.map(&method(:log_key)) + RAW_KEYS).freeze
end

.log_key(key) ⇒ Object 



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# File 'lib/labkit/context.rb', line 62

def log_key(key)
  key = key.to_s
  return key if RAW_KEYS.include?(key)
  return key if key.starts_with?("#{LOG_KEY}.")

  "#{LOG_KEY}.#{key}"
end

.pop(context) ⇒ Object 



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# File 'lib/labkit/context.rb', line 50

def pop(context)
  contexts.pop while contexts.include?(context)
end

.push(new_attributes = {}) ⇒ Object 



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# File 'lib/labkit/context.rb', line 42

def push(new_attributes = {})
  new_context = current&.merge(new_attributes) || new(new_attributes)

  contexts.push(new_context)

  new_context
end

.with_context(attributes = {}) ⇒ Object 



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# File 'lib/labkit/context.rb', line 32

def with_context(attributes = {})
  context = push(attributes)

  begin
    yield(context)
  ensure
    pop(context)
  end
end

Instance Method Details

#correlation_id ⇒ Object 



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# File 'lib/labkit/context.rb', line 102

def correlation_id
  data[CORRELATION_ID_KEY]
end

#get_attribute(attribute) ⇒ Object 



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# File 'lib/labkit/context.rb', line 112

def get_attribute(attribute)
  raw = call_or_value(data[log_key(attribute)])

  call_or_value(raw)
end

#merge(new_attributes) ⇒ Object 



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# File 'lib/labkit/context.rb', line 91

def merge(new_attributes)
  new_context = self.class.new(data.dup)
  new_context.assign_attributes(new_attributes)

  new_context
end

#to_h ⇒ Object 



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# File 'lib/labkit/context.rb', line 98

def to_h
  expand_data
end

#to_headers ⇒ Object 



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# File 'lib/labkit/context.rb', line 106

def to_headers
  to_h.except(CORRELATION_ID_KEY).transform_keys do |key|
    self.class.header_name(key)
  end
end