Module: Datadog::Core::Utils::SpawnMonkeyPatch

Defined in:
lib/datadog/core/utils/spawn_monkey_patch.rb

Overview

Applies the Process.spawn wrapper used to merge additional environment variables into child processes.

Defined Under Namespace

Modules: ProcessSpawnPatch

Class Method Summary collapse

Class Method Details

.apply!(env_provider:) ⇒ Object

Parameters:

  • env_provider (#call) —

    returns a Hash of env vars to merge into the child process



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# File 'lib/datadog/core/utils/spawn_monkey_patch.rb', line 12

def self.apply!(env_provider:)
  @env_provider = env_provider

  # Idempotent: tests, reloads, or repeated Components init must not stack prepends.
  return if ::Process.singleton_class.ancestors.include?(ProcessSpawnPatch)

  ::Process.singleton_class.prepend(ProcessSpawnPatch)
end

.inject_envs(args) ⇒ Object

Merge the env vars from env_provider with the optional env Hash from Process.spawn.

env is the first argument when it is a Hash; see MRI spawn([env, ] *args, options): https://docs.ruby-lang.org/en/master/Process.html#method-c-spawn

When there is no leading env Hash, MRI inherits the parent's ENV; we prepend only the env_provider hash so spawned children see parent env plus injections.

When callers pass unsetenv_others: true, MRI only forwards the explicitly passed env Hash; replacing a missing hash with DATADOG_ENV.to_h would wrongly carry over parent variables. Prepending only the provider hash preserves unsetenv_others semantics.

See https://docs.ruby-lang.org/en/master/Process.html#module-Process-label-Environment+Variables+-28-3Aunsetenv_others-29

NOTE: ::Hash (not bare Hash) is required because this module is nested under Datadog::Core::Utils, and Datadog::Core::Utils::Hash exists. Bare Hash resolves to that module via Module.nesting, making Hash === some_hash silently return false. See https://github.com/DataDog/dd-trace-rb/issues/5621.



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# File 'lib/datadog/core/utils/spawn_monkey_patch.rb', line 54

def self.inject_envs(args)
  provided_env = @env_provider.call

  if ::Hash === args.first
    args[0] = args.first.merge(provided_env)
  else
    args.unshift(provided_env)
  end

  args
end