Pyret Autograder — Gradescope Assignment Template

Template for a pyret-autograder Gradescope assignment, using Gradescope's manual Docker configuration.

Prerequisites

• Docker
• just and jq
• A Docker Hub account. Keep assignment images private so students can't read your wheats/chaffs/tests; Gradescope pulls private images via its gradescopeecs account, which you must add as a collaborator on the repository — this requires a paid Docker Hub plan.

Layout

path	purpose
spec.arr	the grading specification: a list of graders
grading/	support files the spec references — reference implementations, wheats, chaffs
Dockerfile	two-stage build on the pyretautograder/gradescope-{build,run} base images
justfile	build / local-run / publish recipes (just --list)

Paths at runtime

The autograder runs from /autograder, and every path in spec.arr is relative to it:

• the student's submission is unpacked into submission/, so refer to their file as e.g. submission/assignment.arr;
• the contents of grading/ are copied into /autograder, so grading/wheat-1.arr is referred to as just wheat-1.arr.

Workflow

1. Write spec.arr, placing any files it references in grading/. See the grader reference for the available graders.
2. Set image to your Docker Hub repository (and optionally tag) in the justfile.
3. Test locally: place a sample submission in ./submission/ and run just run. The graded report lands in ./results/results.json.
4. just publish.
5. In Gradescope, configure the assignment's autograder as "Manual Docker Configuration" with your username/repository:tag.

Versioning

ARG TAG in the Dockerfile pins the base images; gradescope-build and gradescope-run must use the same tag, which the single ARG ensures. The base images are linux/amd64 only; on Apple Silicon, Docker builds them under emulation.