# Contributing

## Code Style

PEP8 style is used in most cases and flake8 is used for linting by running flake8 in the source directory. The setup.cfg contains the configuration for the linter and lists the error codes and files that are being ignored.

## Building Documentation

Automatic documentation will be created using sphinx so add doc strings to any files created and functions written. Documentation can be compiled with the make_docs.sh bash script.

## Writing Extractors

Extractors are used to take classifications coming out of Panoptes and extract the relevant data needed to calculate a aggregated answer for one task on a subject. Ideally this extraction should be as flat as possible (i.e. no deeply nested dictionaries), but sometimes this can not be avoided.

### 1. Make a new function for the extractor

1. Create a new file for the function in the extractors folder

2. Define a new function *_extractor that takes in the raw classification json (as it appears in the classification dump csv from Panoptes) and returns a dict-like object of the extracted data.

3. Use the @extractor_wrapper decorator on the function (can be imported with from .extractor_wrapper import extractor_wrapper).

4. Use the @subtask_wrapper and @tool_wrapper decorators if the function is for a drawing tool (can be imported with from .extractor_wrapper import subtask_extractor_wrapper).

5. Write tests for the extractor in the tests/extractor_tests folder. The ExtractorTest class from the tests/extractor_tests/base_test_class.py file should be used to create the test function. This class ensures that both the “offline” and “online” versions of the code are tested and produce the expected results. See the other tests in that folder for examples of how to use the ExtractorTest class.

#### The @extractor_wrapper decorator

This decorator removes the boiler plate code that goes along with making a extractor function that works with both the classification dump csv files (offline) and API request from caesar (online). If A request is passed into the function it will pull the data out as json and pass it into the extractor, if anything else is passed in the function will be called directly. This decorator also does the following:

• filter the classifications using the task and tools keywords passed into the extractor

• add the aggregation version number to the final extract

#### The @subtask_extractor_wrapper decorator

This decorator removes the boiler plate code that goes along with extracting subtask data from drawing tasks. This decorator looks for the details keyword passed into the extractor function and will apply the specified extractor the the proper subtask data and return the extracts as a list in the same order the subtask presented them.

Note: It is assumed that the first level of the extracted dictionary refers to the subject’s frame index (e.g. frame0 or frame1) even when the subject only has one frame.

#### The @tool_wrapper decorator

This decorator removes the boiler plate code for filtering classifications based on the tools keyword. This makes it so each tool for a drawing task can have extractors set up independently.

### 2. Create the route to the extractor

The routes are automatically constructed using the extractors dictionary in the __init__.py file:

1. import the new extractor into the __init__.py file with the following format from .*_extractor import *_extractor

2. Add the *_extractor function to the extractors dictionary with a sensible route name as the key (typically the key should be the same as the extractor name)

### 3. Allow the offline version of the code automatically detect this extractor type from a workflow object

1. Update the workflow_config.py function with the new task type. The value used for the type should be the same key used in the __init__.py file

2. Update the tests/utility_tests/test_workflow_config.py test with this new task type

The code is auto-documented using sphinx.

1. Add a doc string to every function written and a “heading” doc string at the top of any new files created (follow the numpy doc string convention)

2. Add a reference to the new file to docs/source/extractors.rst

3. Add to the extractor/reducer lookup table docs/source/Task_lookup_table.rst

4. Build the docs with the make_docs.sh bash script

### 5. Make sure everything still works

1. run nosetests and ensure all tests still pass

2. (optional) nosetests --cover-html to compile an html page for checking what parts of the code are not covered

## Writing Reducers

Reducers are functions that take a list of extracts and combines them into aggregated values. Ideally this reduction should be as flat as possible (i.e. no deeply nested dictionaries), but sometimes this can not be avoided.

### 1. Make new functions for the reducer

Typically two function need to be defined for a reducer.

1. process_data is a helper function that takes a list of raw extracted data objects and pre-processes them into a form the main reducer function can use (e.g. arranging the data into arrays, creating Counter objects, etc…)

2. The *_reducer function that takes in the output of the process_data function and returns the reduced data as a dict-like object.

3. The *_reducer function should use the @reducer_wrapper decorator with the process_data function passed as the process_data keyword.

4. If the reducer exposes keywords the user can specify a DEFAULTS dictionary must be specified of the form: DEFAULTS = {'<keyword name>': {'default': <default value>, 'type': <data type>}}

5. If these keywords are passed into the process_data function they DEFAULTS dictionary should be passed into the @reducer_wrapper as the defaults_process keyword. If these keywords are passed into the main *_reducer function the DEFAULTS dictionary should be passed into the @reducer_wrapper as the defaults_data keyword. Note: any combination of these two can be used.

6. Write tests for all the above functions and place them in the test/reducer_test/ folder. The decorator exposes the original function on the ._original method of the decorated function, this allows for it to be tested directly. The ReducerTest class from the tests/reducer_tests/base_test_class.py file should be used to create the test function. This class ensures that both the “offline” and “online” versions of the code are tested and produce the expected results. See the other tests in that folder for examples of how to use the ReducerTest class.

#### The @reducer_wrapper decorator

This decorator removes the boiler plate needed to set up a reducer function to work with extractions from either a csv file (offline) or an API request from caesar. It will also run an optional process_data data function and pass the results into the wrapped function. Various user defined keywords are also passed into either the process_data function or the wrapped function. All keywords are parsed and type-checked before being used, that way no invalid keywords will be passed into either function. This wrapper will also do the following:

• Remove the aggregation_version keyword from each extract so it is not passed into the reducer function

• Add the aggregation_version keyword to the final reduction dictionary

#### The @subtask_reducer_wrapper decorator

This decorator removes the boiler plate code that goes along with reducing subtask data from drawing tasks. This decorator looks for the details keyword passed into the reducer function and will apply the specified reducer the the proper subtask data within each cluster found on the subject and returns the reductions as a list in the same order the subtask presented them.

Note: It is assumed that the first level of the reduced dictionary refers to the subject’s frame index (e.g. frame0 or frame1) even when the subject only has one frame.

### 2. Create the route to the reducer

The routes are automatically constructed using the reducers dictionary in the __init__.py file:

1. import the new reducer into the __init__.py file with the following format from .*_reducer import *_reducer

2. Add the *_reducer function to the reducer dictionary with a sensible route name as the key (typically the key should be the same as the reducer name)

The code is auto-documented using sphinx.

1. Add a doc string to every function written and a “heading” doc string at the top of any new files created (follow the numpy doc string convention)

2. Add a reference to the new file to docs/source/reducers.rst

3. Add to the extractor/reducer lookup table docs/source/Task_lookup_table.rst

4. Build the docs with the make_docs.sh bash script

### 4. Make sure everything still works

1. run nosetests and ensure all tests still pass (coverage is automatically reported)

2. (optional) nosetests --cover-html to compile an html page for checking what parts of the code are not covered

## Copying extractors and reducers

Sometimes it is useful to have two extractor/reducers routes point to the same underlying function (e.g. question and shortcut tasks), to ensure separate csv files are created in offline mode. Unfortunately if you just place the same function multiple times in the extractors/__init__.py or reducers/__init__.py dictionaries flask will crash since two routes point to functions with the same name. To help with this panoptes_aggregation.copy_function.copy_function can be used to clone any function with a new name:

from panoptes_aggregation.copy_function import copy_function

new_function = copy_function(old_function, 'new_name')