Class: Nonnative::FaultInjectionProxy

Inherits:
Proxy
  • Object
show all
Defined in:
lib/nonnative/fault_injection_proxy.rb

Overview

Fault-injection proxy for TCP services.

This proxy accepts incoming TCP connections and forwards traffic to the configured upstream (service.proxy.host / service.proxy.port) via a socket-pair implementation. It can also inject failures to help validate client resilience.

This class exposes a small public control surface for tests:

  • #close_all: close connections immediately on accept
  • #reset_peer: reset connections immediately on accept (TCP RST rather than a graceful close)
  • #delay: delay reads by a configured duration (default: 2 seconds)
  • #timeout: accept connections and keep them silent until clients time out
  • #invalid_data: forward requests unchanged and mutate upstream responses before they reach clients
  • #bandwidth: throttle forwarded throughput to a configured rate (KB/s)
  • #limit_data: forward a configured number of response bytes, then gracefully close
  • #slicer: forward responses to the client in small writes to force multi-recv reassembly
  • #flaky: fail a configurable fraction of new connections, forwarding the rest normally
  • #reset: return to healthy pass-through behavior

State changes terminate any active connections so new connections observe the new behavior.

Wiring

When enabled, your test/client should connect to the service host and port (the proxy endpoint), and the proxy will forward traffic to the upstream target exposed by #host:#port.

Configuration

The proxy is configured via the service's proxy hash:

  • kind: "fault_injection"
  • host / port: upstream target behind the proxy (exposed via #host/#port)
  • log: file path used by this proxy’s internal logger
  • wait: sleep interval (seconds) applied after state changes
  • options:
    • delay: delay duration in seconds used by #delay
    • jitter: optional random offset (seconds) added in -jitter..jitter to each delay (a negative value uses its magnitude), so clients see variable latency instead of a flat value
    • rate: positive throughput limit in KB/s used by #bandwidth; absent or non-positive values forward at full speed
    • bytes: positive response byte limit used by #limit_data; absent or non-positive values use pass-through behavior
    • slice_size: positive response slice size (bytes) used by #slicer; absent or non-positive values use pass-through behavior
    • slice_delay: optional delay (seconds) between slices used by #slicer
    • probability: connection failure fraction (0.0-1.0) used by #flaky; absent or non-positive values use pass-through behavior

See Also:

Defined Under Namespace

Classes: Connection

Instance Method Summary collapse

Constructor Details

#initialize(service) ⇒ FaultInjectionProxy

Returns a new instance of FaultInjectionProxy.

Parameters:



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# File 'lib/nonnative/fault_injection_proxy.rb', line 71

def initialize(service)
  @connections = Concurrent::Hash.new
  @logger = Logger.new(service.proxy.log)
  @mutex = Mutex.new
  @state = :none

  super
end

Instance Method Details

#bandwidth ⇒ void

This method returns an undefined value.

Throttles forwarded throughput to a configured rate.

The rate is controlled by service.proxy.options[:rate] (kilobytes per second); when it is absent or not positive the connection forwards at full speed.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 165

def bandwidth
  apply_state :bandwidth
end

#close_all ⇒ void

This method returns an undefined value.

Forces new connections to be closed immediately.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 118

def close_all
  apply_state :close_all
end

#delay ⇒ void

This method returns an undefined value.

Delays reads before forwarding.

The delay duration is controlled by service.proxy.options[:delay] and defaults to 2 seconds.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 137

def delay
  apply_state :delay
end

#flaky ⇒ void

This method returns an undefined value.

Fails a configurable fraction of new connections while forwarding the rest normally.

The fraction is controlled by service.proxy.options[:probability] (0.0-1.0); absent or non-positive values behave like pass-through, and 1.0 fails every connection. Because each connection decides independently, clients that retry/reconnect can observe both failures and successes while this state stays active.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 201

def flaky
  apply_state :flaky
end

#host ⇒ String

Returns the upstream host behind this proxy.

Returns:

  • (String) 


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# File 'lib/nonnative/fault_injection_proxy.rb', line 215

def host
  service.proxy.host
end

#invalid_data ⇒ void

This method returns an undefined value.

Mutates upstream responses while forwarding client requests unchanged.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 155

def invalid_data
  apply_state :invalid_data
end

#limit_data ⇒ void

This method returns an undefined value.

Truncates the upstream byte stream after a configured number of bytes.

Client requests are forwarded unchanged. The response byte limit is read from service.proxy.options[:bytes]; when it is absent or not positive, the connection forwards at full speed without truncation.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 176

def limit_data
  apply_state :limit_data
end

#port ⇒ Integer

Returns the upstream port behind this proxy.

Returns:

  • (Integer) 


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# File 'lib/nonnative/fault_injection_proxy.rb', line 222

def port
  service.proxy.port
end

#reset ⇒ void

This method returns an undefined value.

Resets the proxy back to healthy pass-through behavior.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 208

def reset
  apply_state :none
end

#reset_peer ⇒ void

This method returns an undefined value.

Forces new connections to be reset immediately.

Unlike #close_all, which closes the socket gracefully (FIN), this closes the accepted socket with a zero linger timeout so clients observe a TCP reset (Errno::ECONNRESET).



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# File 'lib/nonnative/fault_injection_proxy.rb', line 128

def reset_peer
  apply_state :reset_peer
end

#slicer ⇒ void

This method returns an undefined value.

Fragments upstream responses into small writes before forwarding to the client.

Client requests are forwarded unchanged. Each response is split into service.proxy.options[:slice_size]-byte writes, optionally separated by service.proxy.options[:slice_delay] seconds, so a client's recv returns a strict prefix of the response rather than the whole message. When slice_size is absent or not positive, the connection forwards at full speed without slicing.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 189

def slicer
  apply_state :slicer
end

#start ⇒ void

This method returns an undefined value.

Starts the proxy accept loop in a background thread.

This binds a TCP server on the service host and port. Clients connect to that service endpoint, while upstream traffic is forwarded to #host:#port.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 86

def start
  @tcp_server = ::TCPServer.new(service.host, service.port)
  @thread = Thread.new { perform_start }

  Nonnative.logger.info "started with host '#{service.host}' and port '#{service.port}' for proxy 'fault_injection'"
end

#stop ⇒ void

This method returns an undefined value.

Stops the proxy, closes active connections, and closes its listening socket.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 96

def stop
  server = tcp_server
  server&.close

  listener_thread = thread
  # Closing the server is meant to wake the blocked `accept`, but a concurrently blocked
  # `accept` is not reliably interrupted by `close` on every platform. Kill the listener so
  # `stop` cannot hang joining an accept loop that never woke (a no-op once it has exited).
  listener_thread&.kill
  listener_thread&.join

  @tcp_server = nil
  @thread = nil

  close_connections

  Nonnative.logger.info "stopped with host '#{service.host}' and port '#{service.port}' for proxy 'fault_injection'"
end

#timeout ⇒ void

This method returns an undefined value.

Accepts connections and stalls without forwarding bytes.

This simulates a dependency that accepts a TCP connection but leaves clients waiting until their own read timeout fires. The proxy keeps the connection silent until reset or stop closes active connections.



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# File 'lib/nonnative/fault_injection_proxy.rb', line 148

def timeout
  apply_state :timeout
end