renovate_helper

#!/usr/local/bin/python3
'''
Helper to comment on renovate generated github commits

Currently only deals with Chart.yamls
'''
import os
import subprocess
import logging

from ghapi.all import GhApi
from git import Repo, Actor
#from diff_match_patch import diff_match_patch
import difflib as dl


COMMENT_HEADER='Renovate-helper bot would like to help'
COMMENT_HEADER_VALUES='Renovate-helper bot has mangled values.yaml for you'

def read_file(path):
    with open(path,"r",encoding="utf8") as f:
        contents = f.read()
        return contents

def write_file(path, contents):
    with open(path,"w",encoding="utf8") as f:
        f.write(contents)

def fs_path(path):
    return f"{checkoutPath}/{path}"

def run_capture(cmd, directory, check=True):
    return subprocess.run(args=[cmd],
                          cwd=directory,
                          capture_output=True,
                          shell=True,
                          check=check)


def update_orig_values(chart_dir):
    fs_chart_dir = fs_path(chart_dir)
    logging.info(f"Building helm deps in {chart_dir}")
    run_capture('helm dependency update', fs_chart_dir)
    run_capture('tar -zxf *gz', f"{fs_chart_dir}/charts")
    run_capture('cat charts/*/values.yaml | sed -r -e \'s/^(.*)/  \\1/g\' | sed -r -e \'s/^  $//g\' > orig-values.yaml', fs_chart_dir)
    repo.index.add(fs_chart_dir+'/orig-values.yaml')

def diff_with_sha(file_path, sha):
    sha_file_path = f"{fs_path(file_path)}.other"

    sha_file_contents = run_capture(f"git show {sha}:{file_path}", checkoutPath)
    write_file(sha_file_path, sha_file_contents.stdout.decode('utf-8'))
    diff = run_capture(f"diff -u {sha_file_path} {fs_path(file_path)}", checkoutPath, check=False)
    os.unlink(sha_file_path)
    return diff

def update_values_comment(chart_dir):
    rej_path = fs_path(f"{chart_dir}/values.yaml.rej")
    if os.path.exists(rej_path):
        rejects = read_file(rej_path)
        comment="<details>\n<summary>I'm sorry, but I didn't patch values.yaml completely. Here are the patches which failed:</summary>\n\n```diff\n"
        comment+=rejects
        comment+="```\n</details>\n"
        return comment

def update_values(chart_dir, merge_base):
    fs_chart_dir = fs_path(chart_dir)

    values_path = f"{chart_dir}/values.yaml"
    values_diff = diff_with_sha(values_path, merge_base)
    logging.info(values_diff.stdout.decode('utf-8'))
    # If values hasn't yet been mangled
    if len(values_diff.stdout.decode('utf-8')) == 0:
        logging.info(f"Attempting to update {values_path}")
        orig_diff = diff_with_sha(f"{chart_dir}/orig-values.yaml", merge_base)
        logging.info(orig_diff.stdout.decode('utf-8'))
        patch_path = f"{fs_chart_dir}/patch"
        write_file(patch_path, orig_diff.stdout.decode('utf-8'))
        run_capture(f"patch -p0 {fs_path(values_path)} <{patch_path}", fs_chart_dir, check=False)
        os.unlink(patch_path)
        repo.index.add(fs_path(values_path))
        return update_values_comment(chart_dir)
    return ""

def handle_chart(chart_path, merge_base):
    '''
    Try to see if a chart needs help. Do a git commit and return a comment if we can help.
    '''
    chart_dir = os.path.dirname(chart_path)
    update_orig_values(chart_dir)
    comment_values_update(update_values(chart_dir, merge_base))

    fs_chart_dir = fs_path(os.path.dirname(chart_path))
    nowlines = run_capture('wc -l orig-values.yaml', fs_chart_dir)
    nowsplit = nowlines.stdout.decode('utf-8').split(" ")
    nowlines = nowsplit[0]
    diffstat = run_capture(f"git diff {merge_base} --numstat -- orig-values.yaml", fs_chart_dir, check=False)
    diffsplit = diffstat.stdout.decode('utf-8').split("\t")
    comment=f"\n\nChart in ```{os.path.dirname(chart_path)}```:\n"
    if len(diffsplit)>1:
        newlines = diffsplit[0]
        dellines = diffsplit[1]
        newpercent = (int(newlines)*100/int(nowlines))
        comment+=f"Of {nowlines} lines now in the upstream values.yaml, {newlines} are added and {dellines} have been removed, something like {newpercent}% difference.\n"

        comment+="<details>\n<summary>Here is the diff between our values.yaml and the new upstream values</summary>\n\n```diff\n"
        result = run_capture('diff -U3 orig-values.yaml values.yaml', fs_chart_dir, check=False)
        comment+=result.stdout.decode('utf-8')
        comment+="```\n</details>\n"
    else:
        comment+="Upstream values.yaml has not changed\n"
    return comment

def try_commit_push():
    '''
    If the git index is dirty, then try commit+push
    '''
    commit_diff = repo.index.diff('HEAD')
    if len(commit_diff) > 0:
        author = Actor(GIT_NAME, GIT_EMAIL)
        repo.index.commit("Renovate-helper: Automated update", author=author, committer=author)

        repo.create_remote('httpsorigin', f"https://{token}@github.com/{GH_OWNER}/{appRepo}")
        repo.remotes.httpsorigin.push().raise_if_error()

def comment_values_update(new_comment):
    if new_comment is not None and len(new_comment) >0 :
        new_comment = COMMENT_HEADER_VALUES+"\n"+new_comment
        api.issues.create_comment(issue_number=prNum,
                                  body=new_comment)

def comment_if_needed(new_comment):
    '''
    If the new_comment doesn't exist as a GH comment, or is different from
    the one starting with COMMENT_HEADER create or update it
    '''
    if new_comment is not None and len(new_comment) >0 :
        new_comment = COMMENT_HEADER+"\n"+new_comment
        existing_comments = api.issues.list_comments(issue_number=prNum)
        found_comment = False
        for comment in existing_comments:
            print(comment.body)
            if comment.body.startswith(COMMENT_HEADER):
                found_comment = True
                if comment != new_comment:
                    api.issues.update_comment(comment_id=comment.id,
                                              body=new_comment)
                break

        if found_comment is False:
            api.issues.create_comment(issue_number=prNum,
                                      body=new_comment)

def process_diff():
    '''
    Process the diff between where we are now and the target branch
    '''
    merge_base = repo.merge_base(gitSha, "origin/"+targetBranch)
    diff = repo.head.commit.diff(merge_base)
    comments = ""
    for diff_modified in diff.iter_change_type('M'):
        if os.path.basename(diff_modified.a_path) == 'Chart.yaml':
            comments += handle_chart(diff_modified.a_path, merge_base[0].hexsha)
    return comments

def main():
    '''
    Main body
    '''
    helper_comment=process_diff()

    print(helper_comment)
    try_commit_push()
    comment_if_needed(helper_comment)
logging.basicConfig(level=logging.INFO)

appRepo=os.environ['APP_REPO']
gitSha=os.environ['GIT_SHA']
targetBranch=os.environ['TARGET_BRANCH']
checkoutPath=os.environ['CHECKOUT_PATH']
prNum=os.environ['PR_NUM']
token=os.environ['GITHUB_TOKEN']
GH_OWNER=os.environ['GH_OWNER']
GIT_EMAIL=os.environ['GIT_EMAIL']
GIT_NAME=os.environ['GIT_NAME']

repo = Repo(checkoutPath)
assert not repo.bare
api = GhApi(token=token,
            owner=GH_OWNER,
            repo=appRepo)

main()