Class: LaunchDarkly::Impl::DataSystem::StreamingDataSource Private

Inherits:
Object
  • Object
show all
Includes:
LaunchDarkly::Interfaces::DataSystem::Synchronizer
Defined in:
lib/ldclient-rb/impl/data_system/streaming.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

StreamingDataSource is a Synchronizer that uses Server-Sent Events (SSE) to receive real-time updates from LaunchDarkly’s Flag Delivery services.

Since:

  • 5.5.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sdk_key, http_config, initial_reconnect_delay, config) ⇒ StreamingDataSource

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of StreamingDataSource.

Parameters:

  • sdk_key (String)
  • http_config (HttpConfigOptions) —

    HTTP connection settings

  • initial_reconnect_delay (Float) —

    Initial delay before reconnecting after an error

  • config (LaunchDarkly::Config) —

    Used for global header settings

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/data_system/streaming.rb', line 39

def initialize(sdk_key, http_config, initial_reconnect_delay, config)
  @sdk_key = sdk_key
  @http_config = http_config
  @initial_reconnect_delay = initial_reconnect_delay
  @config = config
  @logger = config.logger
  @name = "StreamingDataSourceV2"
  @sse = nil
  @stopped = Concurrent::Event.new
  @diagnostic_accumulator = nil
  @connection_attempt_start_time = 0
end

Instance Attribute Details

#name ⇒ Object (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/data_system/streaming.rb', line 31

def name
  @name
end

Instance Method Details

#set_diagnostic_accumulator(diagnostic_accumulator) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Sets the diagnostic accumulator for streaming initialization metrics.

Parameters:

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/data_system/streaming.rb', line 57

def set_diagnostic_accumulator(diagnostic_accumulator)
  @diagnostic_accumulator = diagnostic_accumulator
end

#stop ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Stops the streaming synchronizer.

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/data_system/streaming.rb', line 201

def stop
  @logger.info { "[LDClient] Stopping StreamingDataSourceV2 synchronizer" }
  @sse&.close
  @stopped.set
end

#sync(ss) {|update| ... } ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

sync begins the synchronization process for the data source, yielding Update objects until the connection is closed or an unrecoverable error occurs.

Parameters:

Yield Parameters:

Since:

  • 5.5.0



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# File 'lib/ldclient-rb/impl/data_system/streaming.rb', line 69

def sync(ss)
  @logger.info { "[LDClient] Starting StreamingDataSourceV2 synchronizer" }
  log_connection_started

  change_set_builder = LaunchDarkly::Interfaces::DataSystem::ChangeSetBuilder.new
  envid = nil
  # The FDv1 Fallback Directive is one-way and terminal: once any
  # connect handshake within this sync invocation carries it, the SDK
  # is committed to engaging FDv1 as soon as the next full payload
  # has been applied. We therefore latch this flag to true on first
  # observation and never reset it -- a mid-sync reconnect whose
  # response no longer carries the directive does NOT cancel a
  # directive seen earlier. This matches the Go and Python SDK
  # implementations, both of which use the same latch pattern.
  #
  # The flag has to bridge two callbacks: on_connect sees the response
  # headers but on_event does not. A local closed over by both blocks
  # is correct because:
  #   1. Scope -- bound to a single sync invocation, so a future sync
  #      starts fresh. (Within this invocation, persistence across
  #      reconnects is the intended semantics, per above.)
  #   2. Thread safety -- ld-eventsource dispatches on_connect,
  #      on_event, and on_error on the same SSE worker thread, so
  #      reads and writes here are single-threaded by construction.
  fdv1_fallback_pending = false

  base_uri = @http_config.base_uri + FDV2_STREAMING_ENDPOINT
  headers = Impl::Util.default_http_headers(@sdk_key, @config)
  opts = {
    headers: headers,
    read_timeout: STREAM_READ_TIMEOUT,
    logger: @logger,
    socket_factory: @http_config.socket_factory,
    reconnect_time: @initial_reconnect_delay,
  }

  @sse = SSE::Client.new(base_uri, **opts) do |client|
    client.on_connect do |headers|
      if headers
        # Per-environment identifier: server sends it on every connect,
        # but it never changes once known so only assign once.
        envid ||= LaunchDarkly::Impl::DataSystem.lookup_header(headers, LD_ENVID_HEADER)
        fdv1_fallback_pending = true if LaunchDarkly::Impl::DataSystem.fdv1_fallback_requested?(headers)
      end
    end

    client.on_event do |event|
      begin
        update = process_message(event, change_set_builder, envid, fdv1_fallback_pending: fdv1_fallback_pending)
        next unless update

        log_connection_result(true)
        @connection_attempt_start_time = 0

        yield update

        # When the FDv1 Fallback Directive rode along on a Valid update, close
        # the stream so the primary synchronizer is stopped once the directive
        # engages. process_message marks the Update with fallback_to_fdv1 only
        # on payloads that complete a transfer, so the consumer has already
        # applied the ChangeSet by the time we get here.
        if update.fallback_to_fdv1
          fdv1_fallback_pending = false
          stop
        end
      rescue JSON::ParserError => e
        @logger.info { "[LDClient] Error parsing stream event; will restart stream: #{e}" }
        yield LaunchDarkly::Interfaces::DataSystem::Update.new(
          state: LaunchDarkly::Interfaces::DataSource::Status::INTERRUPTED,
          error: LaunchDarkly::Interfaces::DataSource::ErrorInfo.new(
            LaunchDarkly::Interfaces::DataSource::ErrorInfo::INVALID_DATA,
            0,
            e.to_s,
            Time.now
          ),
          environment_id: envid
        )

        # Re-raise the exception so the SSE implementation can catch it and restart the stream.
        raise
      rescue => e
        @logger.info { "[LDClient] Error while handling stream event; will restart stream: #{e}" }
        yield LaunchDarkly::Interfaces::DataSystem::Update.new(
          state: LaunchDarkly::Interfaces::DataSource::Status::INTERRUPTED,
          error: LaunchDarkly::Interfaces::DataSource::ErrorInfo.new(
            LaunchDarkly::Interfaces::DataSource::ErrorInfo::UNKNOWN,
            0,
            e.to_s,
            Time.now
          ),
          environment_id: envid
        )

        # Re-raise the exception so the SSE implementation can catch it and restart the stream.
        raise
      end
    end

    client.on_error do |error|
      log_connection_result(false)
      fallback = false

      if error.respond_to?(:headers) && error.headers
        envid ||= LaunchDarkly::Impl::DataSystem.lookup_header(error.headers, LD_ENVID_HEADER)
        fallback = true if LaunchDarkly::Impl::DataSystem.fdv1_fallback_requested?(error.headers)
      end

      update = handle_error(error, envid, fallback)
      yield update if update
    end

    client.query_params do
      selector = ss.selector
      {
        "filter" => @config.payload_filter_key,
        "basis" => (selector.state if selector&.defined?),
      }.compact
    end
  end

  unless @sse
    @logger.error { "[LDClient] Failed to create SSE client for streaming updates" }
    return
  end

  # Client auto-starts in background thread. Wait here until stop() is called.
  @stopped.wait
end