Add a script to render imported tasks' dependencies to PDF

scripts/github-dependencies.py

@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+
+import argparse
+import itertools
+import re
+import subprocess
+import sys
+from pathlib import Path
+from typing import Collection, Dict, Iterable, List, Optional
+
+import github
+from import_backends import get_github_credential
+
+
+def dropuntil(iterable: List[str], key: str) -> Iterable[str]:
+    found = False
+    for x in iterable:
+        if found and x:
+            yield x
+        found = found or x == key
+
+
+def parse_issue_id(text: str) -> Optional[int]:
+    match = re.search(r'#(\d+) ', text)
+    if match is not None:
+        return int(match.group(1))
+    return None
+
+
+class GitHubBackend:
+    def __init__(self, repo_name: str, milestones: Collection[str]) -> None:
+        self.github = github.Github(get_github_credential())
+        self.repo = self.github.get_repo(repo_name)
+
+        self.milestones: Dict[str, github.Milestone.Milestone] = {
+            x.title: x for x in self.repo.get_milestones()
+        }
+
+        self.labels: Dict[str, github.Label.Label] = {
+            x.name: x for x in self.repo.get_labels()
+        }
+
+        self.issues: Dict[int, github.Issue.Issue] = {
+            x.number: x for x in itertools.chain.from_iterable(
+                self.repo.get_issues(
+                    state='all',
+                    milestone=self.milestones[m],
+                )
+                for m in milestones
+            )
+        }
+
+        self.dependencies: Dict[int, List[int]] = {
+            x: self.get_dependencies(x) for x in self.issues.keys()
+        }
+
+    def get_issue(self, number: int) -> Optional[github.Issue.Issue]:
+        try:
+            return self.issues[number]
+        except KeyError:
+            print(f"Warning: unknown issue {number}", file=sys.stderr)
+            return None
+
+    def get_dependencies(self, number: int) -> List[int]:
+        issue = self.get_issue(number)
+        if not issue or not issue.body:
+            return []
+
+        lines = dropuntil(issue.body.splitlines(), key='### Dependencies')
+        parsed = [parse_issue_id(y) for y in lines]
+        return [x for x in parsed if x is not None]
+
+    def as_dot(self) -> str:
+        def issue_as_dot(number: int, deps: List[int]) -> str:
+            issue = self.get_issue(number)
+            if issue is None:
+                raise ValueError(number)
+
+            deps_str = ' '.join(str(y) for y in deps)
+            title = issue.title.replace('"', '\\"')
+            colour = "black"
+
+            if issue.state == 'closed':
+                title = f"{title} (closed)"
+                colour = "grey"
+
+            return "\n".join((
+                f'    {number} [ label="{title}" fontcolor={colour} color={colour} ]',
+                f'    {number} -> {{ {deps_str} }}',
+            ))
+
+        body = "\n".join(
+            issue_as_dot(number, deps)
+            for number, deps in self.dependencies.items()
+        )
+        return f"digraph {{ {body} }}"
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(
+        description="Fetch tasks from GitHub and render a tree showing dependencies",
+    )
+    parser.add_argument(
+        '--github-repo',
+        help="GitHub repository name (default: %(default)s)",
+        default='srobo/tasks',
+    )
+    parser.add_argument(
+        'milestones',
+        nargs=argparse.ONE_OR_MORE,
+        help="The milestones to pull tasks from",
+    )
+    parser.add_argument(
+        '--output',
+        type=Path,
+        help="Where to output the dependencies PDF",
+    )
+
+    return parser.parse_args()
+
+
+def main(arguments: argparse.Namespace) -> None:
+    backend = GitHubBackend(
+        arguments.github_repo,
+        arguments.milestones,
+    )
+
+    dot = backend.as_dot()
+
+    with arguments.output.open(mode='wb') as f:
+        subprocess.run(
+            ['dot', '-Grankdir=LR', '-Tpdf'],
+            input=dot.encode(),
+            stdout=f,
+            check=True,
+        )
+
+
+if __name__ == '__main__':
+    main(parse_args())