milestone.md

Milestones

High Priority (Quick Wins)

1. Fix filename bug

${image}.tar.gz breaks when $image contains / (e.g., library/hello-world):

imageFile="${image//\//_}"  # use existing var, already defined in script
tar -cvC "${dir}" . | gzip -c -9 >"${imageFile}.tar.gz"

2. Quote all variables

Unquoted variables break on paths with spaces:

# Bad:
dn $blobRedirect $targetFile
# Good:
dn "$blobRedirect" "$targetFile"

3. Check all dependencies at startup

Currently only checks curl and jq, missing aria2c, tar, gzip, docker:

for cmd in curl jq aria2c tar gzip docker; do
    if ! command -v "$cmd" &>/dev/null; then
        echo >&2 "error: \"$cmd\" not found!"
        exit 1
    fi
done

4. Proper CLI flags

Replace positional args with flags:

./docker_dn -d output_dir -i hello-world:latest
./docker_dn -h  # help

---

Medium Priority

5. Multi-registry support

Add support for other registries:

Registry	Base URL
GCR	gcr.io
GHCR	ghcr.io
Quay	quay.io

Detection logic: parse image prefix → set registry base URL.

6. Resume on failure

Track completed layers in a state file. On restart, skip completed layers.

7. Cleanup on failure

Trap errors and remove partial downloads:

cleanup() { rm -rf "$dir"; }
trap cleanup ERR

---

Low Priority

8. Consider rewriting in Python

The Bash script is already ~480 lines with complex logic (HTTP redirects, JSON parsing, state management). Python would:

• Better error handling
• Easier multi-registry support
• Proper argument parsing with argparse
• requests library handles redirects/headers cleanly
• Cross-platform without bash version hacks

9. Batch download support

Read a list of images from a file:

./docker_dn -f images.txt  # downloads all images in file

10. Checksum verification

Verify downloaded layer integrity against manifest digests.