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Version: edge

The null Connector

::: info

This connector is not intended for production use, but for testing the Tremor runtime itself. To enable it pass --debug-connectors to tremor.

:::

The null connector is a connector that is used during development.

Events sent to its source are discarded on receive.

Events sent to its sink are discarded on receive.

Configuration​

There is no specific configuration required for this connector

example.troy
  define connector nil from `null`;

A null integration test​

Although designed for tests written in the rust programming language rather than the integration test framework, it could be used in an integration test as follows:

config.troy
define flow main
flow
  use integration;

  define connector nil from `null`;
  create connector nil;

  create connector exit from integration::exit;
  create connector out from integration::write_file;
  create connector in from integration::read_file;
  create pipeline main from integration::out_or_exit;

  connect /connector/in to /pipeline/main;
  connect /pipeline/main to /connector/out;
  connect /pipeline/main to /connector/nil;
  connect /pipeline/main/exit to /connector/nil;
  connect /pipeline/main/exit to /connector/exit;
  
end;
deploy flow main;

We can then execute the test as follows

$ export TREMOR_PATH=/path/to/tremor-runtime/tremor-script/lib:/path/to/tremor-runtime/tremor-cli/tests/lib
$ tremor test integration .

Constraints​

It is an error to attempt to run any deployment using the null connector via the regular server execution command in the tremor command line interface

➜  null-exit git:(main) ✗ tremor server run config.troy
tremor version: 0.12
tremor instance: tremor
rd_kafka version: 0x000002ff, 1.8.2
allocator: snmalloc
[2022-04-12T15:28:23Z ERROR tremor_runtime::system] Error starting deployment of flow main: Unknown connector type null
Error: An error occurred while loading the file `config.troy`: Error deploying Flow main: Unknown connector type null
[2022-04-12T15:28:23Z ERROR tremor::server] Error: An error occurred while loading the file `config.troy`: Error deploying Flow main: Unknown connector type null
We are SHUTTING DOWN due to errors during initialization!
[2022-04-12T15:28:23Z ERROR tremor::server] We are SHUTTING DOWN due to errors during initialization!