Haskall on CircleCI

circle.yml

version: 2
defaults: &defaults
  environment:
    BASH_ENV: ~/.bashrc
    
    # These libraries eat up a lot of memory while compiling and cannot be built in parallel with other libraries.
    $ They will exhaust your memory and cause the build to crash if not built separately.
    KNOWN_CULPRITS: "regex-tdfa lens"
    
    # Space separated list of files that you want to finally deploy
    ARTEFACTS: ".stack-work/install/x86_64-linux/lts-9.0/8.0.2/bin/webservice-exe templates"
    
    # Can be used for the deployment script below, if you need it.
    APP_ENV: production
    YAML_PARSER: .circleci/get_key_from_yaml.py
jobs:
  build:
    <<: *defaults

    # If you have a pre-compiled docker image in some docker container reposotiry, you can comment lines 21 & 22
    # and uncomment lines 17-21 and change them to use your own docker image, instaed of the one by CircleCI
    # docker:
    #   - image: saurabhnanda/vl-haskell:ubuntu-14.04
    #     auth:
    #       username: $DOCKERHUB_USERNAME # this is fetched from the "Project Settings" tab on the CircleCI UI
    #       password: $DOCKERHUB_PASSWORD # this is fetched from the "Project Settings" tab on the CircleCI UI
    docker:
      - image: circleci/ubuntu-server
      
    # CHANGE THE FOLLOWING
    working_directory: ~/usually-your-project-name
    steps:
      - run:
          # Lines 32-34 are required if you aren't using a custom docker image. They are to install some system-wide/C libraries that your Haskell code may depende on.
          name: "Figuring out the SHA-checksums of last 10 commits"
          command: |
            apt-get update
            apt-get install -y --force-yes curl
            apt-get install -y --force-yes --no-install-recommends make xz-utils libpq-dev libicu-dev libblas-dev liblapack-dev libgmp3-dev clang gcc git-core
            printf 'Host *\n\tStrictHostKeyChecking no\n' >> ~/.ssh/config && chmod 400 ~/.ssh/config
            git clone -b $CIRCLE_BRANCH --single-branch --depth=10 $CIRCLE_REPOSITORY_URL /tmp/repo
            i=1; for sha in $(cd /tmp/repo && git log -n 10 --pretty='%H'); do echo $sha > ~/commit-sha$i.txt && let i+=1; done
      - restore_cache:
          keys:
            - v4-source-code-{{ checksum "~/commit-sha1.txt" }} # <=== this is the current commit, will this ever be in cache?
            - v4-source-code-{{ checksum "~/commit-sha2.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha3.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha4.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha5.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha6.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha7.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha8.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha9.txt" }}
            - v4-source-code-{{ checksum "~/commit-sha10.txt" }}
      - run:
          name: Fetching latest source code and checking out the current commit
          command: |
            printf 'Host *\n\tStrictHostKeyChecking no\n' >> ~/.ssh/config && chmod 400 ~/.ssh/config
            if ! git status; then git clone YOUR_GIT_REPO_URL ~/usually-your-project-name; fi
            git fetch --all
            git reset --hard HEAD
            git checkout $CIRCLE_SHA1
      - run:
          name: Installing snapshot dependencies for the Haskell project
          no_output_timeout: 2400
          command: |
            export PATH="$HOME/.local/bin:$PATH"
            if ! command -v stack; then curl -sSL https://get.haskellstack.org/ | sh && stack setup; fi
            stack setup
            stack build -j1 $KNOWN_CULPRITS --ghc-options="-j -M3.5G -A32m -RTS -O0" --resolver=`$YAML_PARSER stack.yaml resolver`
            stack build --only-snapshot --ghc-options='-j +RTS -M3.5G -sstderr -A32m -RTS -O0'
      - save_cache:
          key: v7-haskell-project-deps
          paths:
            - ~/.local/bin
            - ~/.stack
      - run:
          name: Compiling the Haskell project
          no_output_timeout: 2400
          command: |
            export PATH="$HOME/.local/bin:$PATH"
            stack build --dump-logs --ghc-options='-j +RTS -M3G -sstderr -A32m -RTS -O0'

      - run:
          name: Copying the build artifacts
          command: |
            mkdir ~/artefacts
            cp -R $ARTEFACTS ~/artefacts

      - save_cache:
          key: v4-source-code-{{ checksum "~/commit-sha1.txt" }}
          when: always
          paths:
          # REMEMBER TO CHANGE THIS
            - ~/usually-you-project-name
      - persist_to_workspace:
          # Must be an absolute path, or relative path from working_directory
          root: /root
          paths:
            - artefacts/
  deploy:
    <<: *defaults
    
    # REMEMBER TO CHANGE THIS
    working_directory: ~/usually-you-project-name
    docker:
      - image: circleci/ubuntu-server
    steps:
      - attach_workspace:
          # Must be absolute path or relative path from working_directory
          at: /tmp/artefacts
      - deploy:
          name: Copying all build artefacts to remote server and signalling haproxy restart
          command: |
            # TODO -- write your deployment script here, else you can get rid of this step and the workflow as well.
            

workflows:
  version: 2
  build_and_deploy:
    jobs:
      - build
      - hold-deploy:
          type: approval
          requires:
            - build
      - deploy:
          requires:
            - hold-deploy