pythia

formerly known as foresight

Outputs the emails for each person with >20% ownership of any file in your commit. Involving these owners in communication about changes to files they own has been shown to reduce the number of bugs in research done by microsoft.

For further reading see:

• https://www.microsoft.com/en-us/research/publication/the-influence-of-organizational-structure-on-software-quality-an-empirical-case-study/
• https://www.microsoft.com/en-us/research/publication/dont-touch-my-code-examining-the-effects-of-ownership-on-software-quality/

usage

npm i -g pythia

Then you will have pythia as a command that you can run from your console!

requesting reviewers

Adding -p or --publish to pythia will run the publish config and send the list of reviewers to your code review system. It does this by calling .pythia-publish passing it the email of the author, ownership percentage, and location of the file. You can write a .pythia-publish file to do whatever you need it to do for your review system.

Three arguments are passed in a call that looks like:

./.pythia-publish [email protected] 93.25 somefile-path.md

So in bash that means

$1 = author's email
$2 = percentage of ownership
$3 = the file that is owned

Just to reiterate: .pythia-publish will be called once per author and the first argument to it will be the author's email.

Also: the .pythia-publish file needs to be executable (chmod +x .pythia-publish) and located in the root of your project (which is where you should call pythia from).

Publish File Examples

Gerrit

For gerrit you might do something like this:

#! /bin/sh

ssh -p 29418 [email protected] gerrit set-reviewers -p my-project my-change-id-here -a $1

Github

For github you might do something like this:

#! /bin/sh

TEAM=(["[email protected]"]="designfrontier" ["[email protected]"]="githubusername")

curl "https://api.github.com/repos/$REPO_OWNER/$PROJECT_NAME/pulls/$PULL_REQUEST_NUMBER/requested_reviewers?access_token=$GITHUB_TOKEN" -H "Content-Type: application/json" -X POST -d "{\"reviewers\":[\"${TEAM[$1]}\"]}"

For github to work all of the variables there will need to be set in the env in a way that lets the .pithia.publish call access them. If you set them in your call to pythia they should be passed through to the call to the publish script.

config file

You can create a .pythia-config file in the root of your project in order to exclude users, directories, or files from being processed and reported. This is useful when people leave your team, or when you have files and directories that are auto-generated.

The config file also allows you to change the threshold of ownership that adds people to the review, and outputs their names. By default only users with 20% or greater ownership of a file are output, and sent to yhe publish script. Now you can change that to any number you would like (though >=20% is the number most supported by the research).

The .pythia-config file should be a JSON formatted file and its contents should look like this:

{
  "exclude": {
    "users": ["[email protected]", "[email protected]", "[email protected]"],
    "files": ["readme.md", "history.md", "AUTHORS"],
    "shas": ["1acdb7ea77d8afec3e5bc2cd021c914ca4302265", "e488831"]
    "directories": ["bin"],
    "comments": { ".rb": "#", ".js": "//" }
  },
  "threshold": 20
}

With exclude.comments, you can exclude lines starting with specific characters for the given file extensions.

command line argument

You may also pass the location of your config file ar runtime with the --config option. This allows you to store your config in whatever file you would like. It still needs to conform to the structure laid out above though.

As an example: pythia --config pythia.json where pythia.json is at the root of your project.