Class: LaunchDarkly::Impl::Migrations::Migrator

Inherits:
Object
  • Object
show all
Includes:
LaunchDarkly::Interfaces::Migrations::Migrator
Defined in:
lib/ldclient-rb/impl/migrations/migrator.rb

Overview

An implementation of the [LaunchDarkly::Interfaces::Migrations::Migrator] interface, capable of supporting feature-flag backed technology migrations.

Since:

  • 5.5.0

Instance Method Summary collapse

Constructor Details

#initialize(client, read_execution_order, read_config, write_config, measure_latency, measure_errors) ⇒ Migrator

Returns a new instance of Migrator.

Parameters:

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/migrations/migrator.rb', line 67

def initialize(client, read_execution_order, read_config, write_config, measure_latency, measure_errors)
  @client = client
  @read_execution_order = read_execution_order
  @read_config = read_config
  @write_config = write_config
  @measure_latency = measure_latency
  @measure_errors = measure_errors
  @sampler = LaunchDarkly::Impl::Sampler.new(Random.new)
end

Instance Method Details

#read(key, context, default_stage, payload = nil) ⇒ LaunchDarkly::Migrations::OperationResult

Perform the configured read operations against the appropriate old and/or new origins.

Parameters:

  • key (String) —

    The migration-based flag key to use for determining migration stages

  • context (LaunchDarkly::LDContext) —

    The context to use for evaluating the migration flag

  • default_stage (Symbol) —

    The stage to fallback to if one could not be determined for the requested flag

  • payload (String) (defaults to: nil) —

    An optional payload to pass through to the configured read operations.

Returns:

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/migrations/migrator.rb', line 87

def read(key, context, default_stage, payload = nil)
  stage, tracker = @client.migration_variation(key, context, default_stage)
  tracker.operation(LaunchDarkly::Migrations::OP_READ)

  old = Executor.new(@client.logger, LaunchDarkly::Migrations::ORIGIN_OLD, @read_config.old, tracker, @measure_latency, @measure_errors, payload)
  new = Executor.new(@client.logger, LaunchDarkly::Migrations::ORIGIN_NEW, @read_config.new, tracker, @measure_latency, @measure_errors, payload)

  case stage
  when LaunchDarkly::Migrations::STAGE_OFF
    result = old.run
  when LaunchDarkly::Migrations::STAGE_DUALWRITE
    result = old.run
  when LaunchDarkly::Migrations::STAGE_SHADOW
    result = read_both(old, new, @read_config.comparison, @read_execution_order, tracker)
  when LaunchDarkly::Migrations::STAGE_LIVE
    result = read_both(new, old, @read_config.comparison, @read_execution_order, tracker)
  when LaunchDarkly::Migrations::STAGE_RAMPDOWN
    result = new.run
  when LaunchDarkly::Migrations::STAGE_COMPLETE
    result = new.run
  else
    result = LaunchDarkly::Migrations::OperationResult.new(
      LaunchDarkly::Migrations::ORIGIN_OLD,
      LaunchDarkly::Result.fail("invalid stage #{stage}; cannot execute read")
    )
  end

  @client.track_migration_op(tracker)

  result
end

#write(key, context, default_stage, payload = nil) ⇒ LaunchDarkly::Migrations::WriteResult

Perform the configured write operations against the appropriate old and/or new origins.

Parameters:

  • key (String) —

    The migration-based flag key to use for determining migration stages

  • context (LaunchDarkly::LDContext) —

    The context to use for evaluating the migration flag

  • default_stage (Symbol) —

    The stage to fallback to if one could not be determined for the requested flag

  • payload (String) (defaults to: nil) —

    An optional payload to pass through to the configured write operations.

Returns:

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/migrations/migrator.rb', line 129

def write(key, context, default_stage, payload = nil)
  stage, tracker = @client.migration_variation(key, context, default_stage)
  tracker.operation(LaunchDarkly::Migrations::OP_WRITE)

  old = Executor.new(@client.logger, LaunchDarkly::Migrations::ORIGIN_OLD, @write_config.old, tracker, @measure_latency, @measure_errors, payload)
  new = Executor.new(@client.logger, LaunchDarkly::Migrations::ORIGIN_NEW, @write_config.new, tracker, @measure_latency, @measure_errors, payload)

  case stage
  when LaunchDarkly::Migrations::STAGE_OFF
    result = old.run()
    write_result = LaunchDarkly::Migrations::WriteResult.new(result)
  when LaunchDarkly::Migrations::STAGE_DUALWRITE
    authoritative_result, nonauthoritative_result = write_both(old, new, tracker)
    write_result = LaunchDarkly::Migrations::WriteResult.new(authoritative_result, nonauthoritative_result)
  when LaunchDarkly::Migrations::STAGE_SHADOW
    authoritative_result, nonauthoritative_result = write_both(old, new, tracker)
    write_result = LaunchDarkly::Migrations::WriteResult.new(authoritative_result, nonauthoritative_result)
  when LaunchDarkly::Migrations::STAGE_LIVE
    authoritative_result, nonauthoritative_result = write_both(new, old, tracker)
    write_result = LaunchDarkly::Migrations::WriteResult.new(authoritative_result, nonauthoritative_result)
  when LaunchDarkly::Migrations::STAGE_RAMPDOWN
    authoritative_result, nonauthoritative_result = write_both(new, old, tracker)
    write_result = LaunchDarkly::Migrations::WriteResult.new(authoritative_result, nonauthoritative_result)
  when LaunchDarkly::Migrations::STAGE_COMPLETE
    result = new.run()
    write_result = LaunchDarkly::Migrations::WriteResult.new(result)
  else
    result = LaunchDarkly::Migrations::OperationResult.fail(
      LaunchDarkly::Migrations::ORIGIN_OLD,
      LaunchDarkly::Result.fail("invalid stage #{stage}; cannot execute write")
    )
    write_result = LaunchDarkly::Migrations::WriteResult.new(result)
  end

  @client.track_migration_op(tracker)

  write_result
end