update_status_on_pr.py

"""
This script runs only on travis to create the status for the latest commit
in the PR.

Reference: https://developer.github.com/v3/repos/statuses/#create-a-status
"""
from __future__ import absolute_import
from __future__ import print_function
import os
import requests

GITHUB_REPO = 'sympy/sympy_gamma'
GITHUB_API_URL = 'https://api.github.com'
GITHUB_API_REF_URL = "%s/repos/%s/git/matching-refs/heads/" % (GITHUB_API_URL, GITHUB_REPO)
GITHUB_API_UPDATE_STATUS_URL = "%s/repos/%s/statuses/" % (GITHUB_API_URL, GITHUB_REPO)
SYMPY_BOT_TOKEN_VAR = 'SYMPY_BOT_TOKEN'


def get_branch_commit_sha(branch_name):
    """Gets the SHA of the last commit of the given branch
    :param branch_name: str name of branch on Github
    :return: str SHA
    """
    response = requests.get(GITHUB_API_REF_URL + branch_name)
    if response.status_code == 200:
        response_json = response.json()
    else:
        raise ValueError('Invalid response from github API')
    return response_json[0]['object']['sha']


def update_pr_status_with_deployment(branch_name, commit_sha):
    """Updates the Status of the commit identified by commit SHA, which is reflected
    at the bottom of the PR, above merge button.
    :param branch_name: str name of branch on github
    :param commit_sha: str SHA
    :return: Response POST request to Github API
    """
    sympy_bot_token = os.environ.get(SYMPY_BOT_TOKEN_VAR)
    deployment_url = "https://%s-dot-sympy-gamma-hrd.appspot.com" % branch_name
    payload = {
        "state": "success",
        "target_url": deployment_url,
        "description": "Deployed to version: %s" % branch_name,
        "context": "PR Deployment"
    }

    headers = {
        'Authorization': 'Bearer %s' % sympy_bot_token,
        'Content-Type': 'application/json'
    }

    update_status_url = GITHUB_API_UPDATE_STATUS_URL + commit_sha
    print("Update status URL: %s" % update_status_url)
    response = requests.post(update_status_url, headers=headers, json=payload)
    print("Response: %s" % response.json())


def main():
    is_on_travis = os.environ.get('TRAVIS')
    if not is_on_travis:
        raise ValueError('This script run only on travis!')
    branch_name = os.environ.get('TRAVIS_BRANCH')
    commit_sha = get_branch_commit_sha(branch_name)
    print("Branch name: %s Commit SHA: %s" % (branch_name, commit_sha))
    print("Creating commit status ...")
    update_pr_status_with_deployment(branch_name, commit_sha)


if __name__ == '__main__':
    main()