├── bin
    ├── release
    ├── detect
    └── compile
└── README.md


/bin/release:
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1 | #!/bin/bash
2 | 
3 | cat << EOF
4 | ---
5 | default_process_types:
6 |   web: bin/main
7 | EOF
8 | 


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/bin/detect:
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 1 | #!/bin/sh
 2 | BUILD_DIR=$1
 3 | if stat -t ${BUILD_DIR}/*.opam.locked >/dev/null 2>&1; then
 4 |     echo "OCaml"
 5 |     exit 0
 6 | elif stat -t ${BUILD_DIR}/*.opam >/dev/null 2>&1; then
 7 |     echo "No .opam.locked file detected" >&2
 8 |     echo "Generate one with [opam lock]" >&2
 9 |     exit 1
10 | else
11 |     echo "No .opam.locked file detected" >&2
12 |     exit 1
13 | fi
14 | 


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/bin/compile:
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 1 | #!/bin/bash
 2 | set -eo pipefail
 3 | 
 4 | BUILD_DIR=$1
 5 | CACHE_DIR=$2
 6 | 
 7 | if [[ ! -e $CACHE_DIR/bin/opam ]]; then
 8 |     echo "opam not cached, downloading"
 9 |     wget https://github.com/ocaml/opam/releases/download/2.0.7/opam-2.0.7-x86_64-linux
10 |     mkdir -p $CACHE_DIR/bin
11 |     install opam-2.0.7-x86_64-linux $CACHE_DIR/bin/opam
12 | fi
13 | export PATH=$CACHE_DIR/bin:$PATH
14 | if [[ -e $CACHE_DIR/.opam ]]; then
15 |     echo ".opam cached"
16 |     cp -r $CACHE_DIR/.opam ~/.opam
17 | else
18 |     echo ".opam not cached, calling init"
19 |     opam init --disable-sandboxing
20 |     opam switch create heroku --empty
21 | fi
22 | cd $BUILD_DIR
23 | pwd
24 | opam switch heroku
25 | eval $(opam env)
26 | echo "Installing deps"
27 | OPAMSOLVERTIMEOUT=6000 opam install . --deps-only --locked -y
28 | eval $(opam env)
29 | echo "Building"
30 | dune build @install
31 | echo $BUILD_DIR
32 | dune install --prefix ~/_build
33 | if [[ -e $BUILD_DIR/Procfile ]]; then
34 |     echo "procfile 1"
35 |     cp $BUILD_DIR/Procfile ~/Procfile
36 | fi
37 | rm -rf $BUILD_DIR
38 | mv ~/_build $BUILD_DIR
39 | if [[ -e ~/Procfile ]]; then
40 |     echo "procfile 2"
41 |     mv ~/Procfile $BUILD_DIR/Procfile
42 | fi
43 | echo "Copying .opam"
44 | rm -rf $CACHE_DIR/.opam && cp -r ~/.opam $CACHE_DIR/.opam
45 | 


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/README.md:
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 1 | # Heroku Buildpack: OCaml
 2 | 
 3 | A buildpack for Heroku and compatible systems, for OCaml applications built by dune with dependencies managed by opam.
 4 | 
 5 | ## How to use
 6 | - Create a Heroku account (or set up a compatible system like [dokku](https://github.com/dokku/dokku))
 7 | - Get a git repository with an OCaml project that can be built by the buildpack (you can use https://github.com/roddyyaga/opium-heroku-example)
 8 | - Clone the repo and run `heroku create some-globally-unique-name --buildpack https://github.com/roddyyaga/heroku-buildpack-ocaml`
 9 | - Run `git push heroku master`
10 | - Go to the Heroku URL and check if the app is running
11 | 
12 | ## Build process
13 | This buildpack is for OCaml projects with:
14 | - Dependencies specified by an opam lockfile in the root directory (you can make one with `opam lock`)
15 | - Binaries that will be built/installed by `dune build @install && dune install` in the root directory
16 | 
17 | The build process will install dependencies, build the project, and then install the project under the directory
18 | where Heroku runs the app. For instance, if your app's entrypoint has a dune `public_name` of `server` then you
19 | should have a `Procfile` with contents `web: bin/server`. If no Procfile is provided, the buildpack will assume
20 | it is `web: bin/main`.
21 | 
22 | As with all Heroku projects, your web server should use the port in the environment variable `PORT`.
23 | 
24 | ## Caching
25 | The buildpack will create an opam switch and cache dependencies after each run. The behaviour should be the same
26 | as developing locally with a switch, where adding one dependency means only that dependency has to be installed
27 | on the next build (rather than any change to the lockfile forcing a complete reinstall).
28 | 
29 | ## Caveats
30 | - opam sandboxing is disabled due to constraints of the Heroku build environment
31 | - Installing external dependencies is currently not supported and might not be possible (there is no package manager
32 |   available in the build environment)
33 | 


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