A PDF merging library built using Rust and Rustler, with precompiled binaries.

• Basically wraps the Merge PDF example from lopdf using Rustler
• Can merge pdfs from binaries or paths
• Uses RustlerPrecompiled so every dev in a project using this library doesn't need Rust installed on their machine.

The package can be installed by adding merge_pdf to your list of dependencies in mix.exs:

def deps do
  [
    {:merge_pdf, "~> 0.5.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/merge_pdf.

This project uses RustlerPrecompiled to distribute precompiled native binaries. For development, you'll build the Rust NIF from source.

• Elixir 1.15+
• Rust toolchain via rustup
• just command runner

just setup

This cleans any stale artifacts and builds the NIF from source. Run this when:

• You first clone the repo
• You switch branches with native code changes
• You get precompilation-related errors

just build    # Rebuild NIF after Rust changes
just test     # Run tests

All development commands use MERGE_PDF_BUILD=true internally to force building from source rather than downloading precompiled binaries.

This project builds precompiled binaries for 9 platforms via GitHub Actions. The release process has two phases: before CI (local verification) and after CI (publishing).

1. Authenticate with Hex.pm: mix hex.user auth
2. Ensure GitHub Actions has write permissions (Settings > Actions > General)

These steps verify everything works before creating a release.

# 1. Bump version in mix.exs and Cargo.toml
just bump-version X.Y.Z

# 2. Verify everything builds and tests pass
#    (This does a clean build from source - catches Rust compilation errors)
just verify-local

# 3. Review and commit the version bump
git diff
git add -p
git commit

# 4. Create the git tag
just tag X.Y.Z

# 5. Push to GitHub (triggers CI to build all 9 platform binaries)
just push-release

At this point, wait for GitHub Actions to complete. All 9 platform builds must succeed.

Once CI completes successfully, the precompiled binaries are attached to the GitHub release. Now generate checksums and publish.

# 6. Download checksums from the GitHub release
#    (This verifies all 9 binaries are downloadable)
just download-checksums

# 7. Inspect the hex package contents
just verify-package

# 8. Publish to hex.pm
just publish

Development:

• just setup - First-time setup, builds NIF from source
• just build - Rebuild NIF from source
• just test - Run tests

Pre-release:

• just verify-local - Clean build + tests (run before tagging)
• just bump-version X.Y.Z - Update version numbers

Release:

• just tag X.Y.Z - Create git tag
• just push-release - Push to GitHub (triggers CI)
• just download-checksums - Download checksums after CI
• just verify-package - Inspect hex package
• just publish - Publish to hex.pm

Utilities:

• just version - Show current version
• just clean - Remove build artifacts
• just --list - List all commands