little-sister-github

GitHub check types for little-sister.

github — one node per configured account — an organization, optionally narrowed to one team, or a personal account — with a child per enabled aspect: open pull requests, Dependabot advisories, code-scanning and secret-scanning alerts, dependency-graph presence, workflow runs and open issues.

github-rate-limit — one node per token, with a line per API budget. Cheap enough to run every minute, and it is what explains a github check that has started skipping its runs.

Every finding is an individually addressable line, so an operator who opens a ticket for one alert can put that line into maintenance and the rest of the aspect keeps reporting.

This file is the front door: what the package needs, how it is installed and configured, and what the token must be allowed to read. How the two checks are built — the client, the run, the budget ledger, what every line on a node and in the log means — is docs/architecture.md; why they are built that way is docs/decisions.md and the records in docs/adr/.

The contract

• Requires little-sister >= 0.3.13 — a floor, never a pin.
• Runs on Python 3.11 or newer — the library's floor, not a higher one of its own.
• Registers two check types: github and github-rate-limit. One import registers both.

Install

# your deployment's pyproject.toml — both come from the index
[project]
# Pin them. A deployment names exact versions so an upgrade is a deliberate edit
# rather than drift; a plugin is the one that declares a floor, because two plugins
# that each pinned could not be installed together.
dependencies = ["little-sister==0.3.17", "little-sister-github==0.1.8"]

# wsgi.py — registrations first, the app last. The order is load-bearing:
# importing little_sister.app builds the engine and loads the check configs, so
# every check type must already be registered. `isort: off` keeps an import
# sorter from quietly reversing that.
# isort: off
import little_sister_github          # noqa: F401  registers both check types
from little_sister.app import app
# isort: on

__all__ = ["app"]                    # without it, lint calls the app import unused

Configure github

Copy examples/github.yaml into your deployment's config/checks/, set owner, kind, team and the token reference, and you are done — one file per team. The credential is a reference, never a value:

type: github
path: /platform/github
secrets:
  token: env://PLATFORM_GITHUB_TOKEN
owner: example-org
kind: organization
team: platform

What the token needs, read by read, is under What the token needs below. Each team's check carries its own credential, so a second team is a second config file rather than a code change.

The settings

The common keys every check has — path, title, about, frequency, timeout, secrets — are little-sister's; timeout: is the whole run's budget here (it used to be spent per request — if you are upgrading, re-read it against your scope). The example file carries a comment per key; this is the same list with its defaults.

owner: may name a person

GitHub has one account namespace with two kinds in it, and owner: takes a login of either kind. kind: says which — organization or user — and it is required. It is declared rather than discovered because every load-time decision is taken from it, and it is verified on every run against GET /users/{login}, because a claim nobody checks decays: GitHub lets a personal account convert to an organization. A disagreement is a refusal naming both the config's claim and GitHub's answer, not a wrong scope. team: is an organization's, so kind: user with a team is refused before the check ever runs.

A personal account's private repositories need its own token. /users/{login}/repos returns public repositories only, however privileged the token — the private ones are listed by /user/repos, and only for the account the token belongs to. When they are out of reach the check's own reading says (public only), because a scope smaller than the one configured otherwise reads exactly like a complete one.

Switching an aspect off

Every aspect runs unless its own block says enabled: false:

secret_scanning:
  enabled: false        # switches off the `secret_scanning_alerts` aspect

A switched-off aspect is skipped whole — no node, none of its API calls, and the rate-limit estimate shrinks with it. No node also means no pin: a maintenance pin held against that node, or against a line under it, matches nothing while the aspect is off. An aspect that says nothing is on, so an aspect a later release adds arrives switched on in configs written before it existed. Switching every aspect off is a config error (ADR-0003, decisions 5 and 7).

The per-aspect display text ships with the type and expands {owner} / {team} from the config, so it is not copied per team. Your deployment's own policy — a remediation deadline, who to notify — goes in that config's subnodes: block, appended to the shipped text with {default}. little-sister reads that block itself, so it works the same way for every branch check type you install.

What it reads

Discovery is one call verifying the declared kind — plus, for a personal account, one asking whose token this is — and then the repository listing, filtered by name_prefix, include_archived and include_forks. Every aspect starts from that one set, narrowed only where an aspect says so. The check's own node carries the discovery coverage reading (expect_min_repos) and the repository roster, and rolls up worst-of its aspects. A severity band's title is a colored circle by severity name — 🔴 critical, 🟠 high, 🟡 medium, 🔵 low, the analysis severities on the same three rungs, ❓ for one this package does not name — and nodes.yaml sets a different title per node path if you want the word. Only stdlib urllib is used — the package has no dependency but little-sister itself.

The table says what each aspect grades. Why it grades that way — why the tree is aspect-first, why a missing dependency graph is red while an open pull request is amber, and what a severity band asserts while it is empty — is ADR-0003 and ADR-0004.

Which of these you can change, and which you cannot. The three banded aspects are graded by settings that exist in order to be overruled — severity_map says what a severity means here, severities says which ones are looked at at all. The other five carry the codes in this table with no knob for them: what a deployment decides about those is whether the aspect runs (enabled: false) and which repositories or titles it skips.

What the token needs

The check works with a classic personal access token and with a fine-grained one; nothing in it cares which, as long as the token may read what an aspect reads. A fine-grained token is issued with the organization as its resource owner and granted the repositories the check should see — every repository the scope will contain, or the listing is quietly shorter than the organization. Read access is enough everywhere; the check writes nothing.

A token that may not read something answers 401 or 403, and the check reports that as a fact about the repository rather than as a failure of the run; a token that may not read the repository list fails discovery, which the node says in as many words. A GitHub App's installation token is not a fit today: it expires after an hour, and little-sister resolves a credential once, at startup.

When GitHub is the one having a bad day

A read that fails is not automatically a finding about the repository, and this type tells the two apart by status (ADR-0002): a 5xx, a dropped connection or a rate limit — retried once — is a line saying could not ask GitHub that grades nothing, while a 404 and a 401 or 403 without a throttle header are answers, and still grade. Because those quiet lines grade nothing, the coverage does: an aspect that could not ask about a repository carries one amber line of its own, GitHub did not answer for 1 of 40 repositories, and the check's own node states the run's total once, with what the run slept, by cause — paused 61s for a GitHub rate limit, paused 3s retrying after GitHub did not answer. A wait GitHub asks for is taken when the run and max_pause can afford it and refused whole when they cannot; when to ask again is your frequency:. If GitHub cannot answer which repositories exist, the check says WARN and reports nothing else, so every aspect keeps what the last good run found; a discovery failure GitHub answered — an owner or team that is not there, a token that may not look — is a defect in your configuration and stays ERROR. The fault table, the throttle reading and the two coverage lines are docs/architecture.md §2 and §3.

The run is skipped before it can exhaust the token

A run is skipped, with a WARN naming the window, when a budget window it would spend cannot afford it: rate_limit_safety_factor times the reads that will land on that window, less what something else is measured to be spending on it. A token has more than one core window, split by request path, and GET /rate_limit reports one of them — for some tokens one nothing spends — so the guard prices each window from the budget headers of this process's own reads, and reads the endpoint only where it knows nothing yet (ADR-0007, decision 3):

skipped this run: 310 API calls left on the window GitHub charges the dependabot, code-scanning and actions reads to (resets in 12min), need > 4×57 for 19 repo(s)

The github-rate-limit check on the same token explains the skipped runs.

github-rate-limit — the API budget

One node per token, with a line per API budget. It is a check type of its own rather than an eighth aspect of github, because a rate limit belongs to the credential and not to an account — the argument is ADR-0001. Reading GET /rate_limit does not count against the budget it reports, so this check can run every minute beside a github check that runs every fifteen, and it keeps reporting through the runs the github check skips for want of budget.

type: github-rate-limit
path: /platform/github-rate-limit
frequency: 1m
secrets:
  token: env://PLATFORM_GITHUB_TOKEN   # the same token you want the budget of
warn_below: 1000                       # the default for every resource below
error_below: 500
# resources:                           # leave the key out to watch core + graphql
#   core:
#   search:
#     warn_below: 10                   # a small budget wants both of its own
#     error_below: 3                   # numbers — error_below is the lower one

One line per resource, each carrying its own verdict, keyed by GitHub's own resource name — so a maintenance pin held against core survives a config that starts watching search next year:

core: 2441 of 5000 requests left, resets in 1min; 269 of it this process's own; ~1250/h of it is spent by something else using this token — the tightest of 2 windows GitHub keeps for this token; the other has 3932 left, resets in 6min
graphql: 5000 of 5000 points left, resets in 59min — as /rate_limit reports it; nothing here has spent it

The line is written from the budget headers on every response this process has had on that token, kept in a ledger for the life of the process, with GET /rate_limit merged in as one more reading: the tightest window grades the resource, and the line says how many windows there are, what the others hold, how much of the window this process itself spent, at what rate something else is spending the token, and — once this process has seen a window open — what it already carried at the first reading (ADR-0007 decision 2). Its own spend is a count of what the ledger recorded, not an estimate, and it is bounded by the ledger's life: it is this process's share since it first saw that window, so on a token a second instance or a pipeline also spends, the rest of used is what the other two clauses are for. After a restart the line is the endpoint's until the first github run refills the memory. What every clause means, and the readings the check refuses to fake, is docs/architecture.md §4.

Grading is on what is left and only on that: the reset time is on the line so you can see a red budget is about to refill, and it does not soften the verdict (ADR-0001, decision 4), and the foreign rate is on the line and not in the grade. warn_below and error_below are compared with the tightest window, so a deployment that tuned them against the endpoint's number may see the node go amber sooner — that is the node telling the truth. The thresholds in force are rendered on the node.

Between runs most of what the github check reads has not changed, so it asks conditionally: it keeps each read's ETag and sends If-None-Match, and GitHub answers 304 Not Modified without charging the primary rate limit — measured, not assumed. The held answer is returned unchanged, so no reading and no line differs from what a full read would have said. Nothing is configured, and the check's own page says how many payloads are held and how many of a run's requests were free (ADR-0011).

The token needs no scopes for this endpoint — but it has to resolve, and it has to be one GitHub accepts. A reference that resolves to nothing pins the check to a visible ERROR before it ever runs; a token GitHub rejects is a 401, which this check reports as could not ask GitHub for the rate limit. Neither is a quiet failure. Copy examples/github-rate-limit.yaml — one file per token, not per team.

Develop

little-sister is declared as a floor — the release that promised the surface this package imports — and it resolves from the index, like any other dependency. There is no [tool.uv.sources] table here, and the committed uv.lock is what a release runs against. To work against a local library checkout, add the redirect and do not commit it: uv reads the sources table of a dependency it resolves from a path or a checkout, so a committed line would follow this package into every deployment that installs it.

# pyproject.toml — locally, never committed
[tool.uv.sources]
little-sister = { git = "file:///path/to/little-sister" }

Restore uv.lock with it. The next uv run — the pre-commit gate is one — rewrites the lock to source = { directory = … }, so a redirect kept out of pyproject.toml can still reach a commit through the lock beside it.

uv sync
uv run ruff check
uv run shellcheck $(git ls-files -- '*.sh' 'hooks/pre-commit')
uv run mypy
uv run mypy --python-version 3.11   # against the floor, not the interpreter you have
uv run pytest -q
# The same gate runs before every commit once the hook is enabled:
git config core.hooksPath hooks

A release runs it once more on a real 3.11, because the floor is a promise a type checker alone cannot keep.

The tests are fixture-based; nothing in this repository calls GitHub.

License

MIT — see LICENSE.