commit c2e0def0fbac26f8262b6304d5aa692392612360 Author: Arturo Filastò <arturo@filasto.net> Date: Fri Jan 22 11:03:56 2016 +0100 Add description of what test helpers are in introduction. * Fix links --- docs/source/writing_test_helpers.rst | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/docs/source/writing_test_helpers.rst b/docs/source/writing_test_helpers.rst index 2206115..d391aa4 100644 --- a/docs/source/writing_test_helpers.rst +++ b/docs/source/writing_test_helpers.rst @@ -1,23 +1,23 @@ Writing Test Helpers ======== -OONI test helpers are... +OONI test helpers are used by OONI nettests to perform their meausrements. They can be used either to establish a ground truth or to exchange information with the probe to determine if some form of network manipulation is happening in the network path between the probe and the backend. Writing a Censorship Directionality Test Helper -------------------------- Our goal is to write an OONI test helper that helps an OONI-probe client determine the directionality of keyword censorship it has detected. To do this our helper will receive "encoded" data from an OONI-probe client, decode that data into a text string, and send the OONI-probe client a confirmation packet and a second packet containing the decoded string. -The OONI-backend code-base has many concise examples of test-helpers that you can build off to create your own. For this tutorial I used the `TCP echo test-helper <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib/testhelpers/tcp_helpers.py#L9-L18>` as my guide. +The OONI-backend code-base has many concise examples of test-helpers that you can build off to create your own. For this tutorial I used the `TCP echo test-helper <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib/testhelpers/tcp_helpers.py#L9-L18>`_ as my guide. -Following this tutorial requires basic knowledge of event-driven programming (specifically 'Twisted'). You will be more than ready to build and implement a test-helper after reading though one or two `tutorials online. <http://krondo.com/?page_id=1327>` +Following this tutorial requires basic knowledge of event-driven programming (specifically 'Twisted'). You will be more than ready to build and implement a test-helper after reading though one or two `tutorials online. <http://krondo.com/?page_id=1327>`_ Creating the test helper -------------- -OONI-backend keeps all the test-helpers in the `oonib/testhelpers directory <https://github.com/TheTorProject/ooni-backend/tree/master/oonib/testhelpers>` Each individual test helper is a twisted service. Most of the current test-helpers consists of a twisted Factory and a twisted Protocol defined in the test helpers directory and a `stock Twisted Server <https://twistedmatrix.com/documents/current/api/twisted.application.internet.html>` that is defined in the backend code. We will follow this model in the tutorial. +OONI-backend keeps all the test-helpers in the `oonib/testhelpers directory <https://github.com/TheTorProject/ooni-backend/tree/master/oonib/testhelpers>`_ Each individual test helper is a twisted service. Most of the current test-helpers consists of a twisted Factory and a twisted Protocol defined in the test helpers directory and a `stock Twisted Server <https://twistedmatrix.com/documents/current/api/twisted.application.internet.html>`_ that is defined in the backend code. We will follow this model in the tutorial. -Because of how simple this example test-helper is the job of our test-helper factory is merely to deploy a single instance of our protocol each time it's buildProtocol method is called. Because we have our factory inheret from the base `Factory object <https://twistedmatrix.com/trac/browser/tags/releases/twisted-15.5.0/twisted/internet/protocol.py#L27>` we merely have to define its ``protocol`` property to point to our protocol.:: +Because of how simple this example test-helper is the job of our test-helper factory is merely to deploy a single instance of our protocol each time it's buildProtocol method is called. Because we have our factory inheret from the base `Factory object <https://twistedmatrix.com/trac/browser/tags/releases/twisted-15.5.0/twisted/internet/protocol.py#L27>`_ we merely have to define its ``protocol`` property to point to our protocol.:: class TCPDirectionalityTestHelper(Factory): """ @@ -26,7 +26,7 @@ Because of how simple this example test-helper is the job of our test-helper fac protocol = TCPDirectionalityTestProtocol -The protocol for this helper needs to do two things. First, upon receiving encoded data it needs to send the OONI-probe client back confirmation that the data has been received. Second, it needs to send the decoded data back to the OONI-probe client. Because we are extending the `Protocol object <https://twistedmatrix.com/trac/browser/tags/releases/twisted-15.5.0/twisted/internet/protocol.py#L512>` we can rewrite its ``dataReceived`` method which is called and passed data whenever it is received.:: +The protocol for this helper needs to do two things. First, upon receiving encoded data it needs to send the OONI-probe client back confirmation that the data has been received. Second, it needs to send the decoded data back to the OONI-probe client. Because we are extending the `Protocol object <https://twistedmatrix.com/trac/browser/tags/releases/twisted-15.5.0/twisted/internet/protocol.py#L512>`_ we can rewrite its ``dataReceived`` method which is called and passed data whenever it is received.:: class TCPDirectionalityTestProtocol(Protocol): @@ -68,7 +68,7 @@ With this added we have completed the base of simple test-helper and now just ha Adding the helper to the config file ------ -OONI-backend uses a config file located at `/etc/oonibackend.conf <https://github.com/TheTorProject/ooni-backend/blob/master/oonib.conf.example>`. This file contains a `section where each test-helper can be configured. <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib.conf.example#L33-L65>`. +OONI-backend uses a config file located at `/etc/oonibackend.conf <https://github.com/TheTorProject/ooni-backend/blob/master/oonib.conf.example>`_. This file contains a `section where each test-helper can be configured. <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib.conf.example#L33-L65>`_. The test-helper will need to be given a unique identifyer so that it can be called from the config file. In this example we use ``tcp-directionality`` as our identifyer. @@ -81,17 +81,17 @@ For a helper to be used in the ooni-backend it needs to be given an identifyer s Adding the helper to the backend ------ -For a helper to be integrated into the ooni-backend it needs to be added to the initialization scripts contained within `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`. +For a helper to be integrated into the ooni-backend it needs to be added to the initialization scripts contained within `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`_. -The OONI test-helper system is a collection of `Twisted services <https://twistedmatrix.com/documents/current/core/howto/application.html>`. For our test-helper we will need to define a service that will run our test-helper factory.:: +The OONI test-helper system is a collection of `Twisted services <https://twistedmatrix.com/documents/current/core/howto/application.html>`_. For our test-helper we will need to define a service that will run our test-helper factory.:: # Create the service that will run our test-helpers factory. tcp_directionality_helper = internet.TCPServer(int(port), tcp_helpers.TCPDirectionalityTestHelper()) -**NOTE:** In this example I have placed the original service in the existing tcp_helpers file. If you created your own file for your test-helper you will have to make sure that you import that file at the top of `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`. +**NOTE:** In this example I have placed the original service in the existing tcp_helpers file. If you created your own file for your test-helper you will have to make sure that you import that file at the top of `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`_. -OONI uses a `Multi Service <https://twistedmatrix.com/documents/current/api/twisted.application.service.MultiService.html>` which allows them to combine all the OONI test-helpers and the report-collector into a singlular service for easier management. The next step for creating our test-helper is to add it to the OONI-backend `multiService <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib/oonibackend.py#L33>`:: +OONI uses a `Multi Service <https://twistedmatrix.com/documents/current/api/twisted.application.service.MultiService.html>`_ which allows them to combine all the OONI test-helpers and the report-collector into a singlular service for easier management. The next step for creating our test-helper is to add it to the OONI-backend `multiService <https://github.com/TheTorProject/ooni-backend/blob/479a1bb154037b834292ccc4b3d593d1472b44de/oonib/oonibackend.py#L33>`_:: # Add the helper as a child of the backends multi-service test-helper multiService.addService(tcp_directionality_helper) @@ -103,7 +103,7 @@ Finally, we need to start our service.:: In order for our test-helper to be managed using the backend config file we will need to modify this code to check the config file for a test-helper that uses the identifyer we selected earlier. For the directionality helper we check to see if our test-helper had its port specified in the config file to determine if it should be run. I also added a default encoding in case -This snippet contains the final code that would be inserted into `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`.:: +This snippet contains the final code that would be inserted into `oonibackend.py <https://github.com/TheTorProject/ooni-backend/blob/master/oonib/oonibackend.py>`_.:: # Check to see if our test-helper was defined in the config if config.helpers['tcp-directionality'].port: