Script for managing prisma engines versions

prisma-engine.sh

# Instructions
# 1. Download this script
# 2. Add `source /path/to/the/script.sh` to your shell profile
# 3. Reload the shell
# 4. Use the command:
#   - `prisma-engine use /path/to/checkout/dir` for local checkout
#   - `prisma-engine use 12345` for github pull requests
#   - `prisma-engine unuse` for resetting all env variables and switching back
#   to default engine

function _prisma-engine() (
    set -euo pipefail
    local ROOT_DIR="$HOME/.prisma-engine"
    local CHECKOUT_DIR="$ROOT_DIR/checkout"
    local CHECKOUT_GIT_DIR="$ROOT_DIR/checkout/.git"
    local NODE_API_LIB="$ROOT_DIR/libquery_engine.dylib.node"

    local ENGINES_REPO="https://github.com/prisma/prisma-engines.git"
    echoerr() { echo "$@" 1>&2; }

    print_usage() {
        echoerr 'Usage:'
        echoerr 'prisma-engine use <path to engine dir>'
        echoerr 'prisma-engine use <github pr id>'
        echoerr 'prisma-engine unuse'
        return 1
    }

    checkout_git() {
        git --git-dir="$CHECKOUT_GIT_DIR" --work-tree="$CHECKOUT_DIR" $@ 1>&2
    }

    use() {
        if [ -z "$1" ]; then
            print_usage
            return $?
        fi

        local ENDMSG=""
        local ENGINE_DIR=""

        mkdir -p "$ROOT_DIR"

        if [ -d "$1" ]; then
            ENGINE_DIR=$(cd $1;pwd)
            ENDMSG="Now using engine from $ENGINE_DIR"
        else
            # if it is not a local path, presume github PR
            if ! [ -d "$CHECKOUT_DIR" ]; then 
                git clone --depth=1  "$ENGINES_REPO" "$CHECKOUT_DIR"
            fi

            checkout_git fetch --depth=1 origin "pull/$1/head"
            checkout_git checkout FETCH_HEAD

            ENGINE_DIR="$CHECKOUT_DIR"
            ENDMSG="Now using engine from Github PR#$1"
        fi

        rm -f "$NODE_API_LIB"

        cargo build --manifest-path "$ENGINE_DIR/Cargo.toml" --debug \
            --package query-engine-node-api \
            --package query-engine \
            --package schema-engine-cli \
            --package prisma-fmt

        cp "$ENGINE_DIR/target/debug/libquery_engine.dylib" "$NODE_API_LIB"
        echo "export PRISMA_QUERY_ENGINE_LIBRARY='$NODE_API_LIB'"
        echo "export PRISMA_QUERY_ENGINE_BINARY='$ENGINE_DIR/target/debug/query-engine'"
        echo "export PRISMA_SCHEMA_ENGINE_BINARY='$ENGINE_DIR/target/debug/schema-engine'"
        echoerr "$ENDMSG"
    }

    unuse() {
        echo 'unset PRISMA_QUERY_ENGINE_LIBRARY'
        echo 'unset PRISMA_QUERY_ENGINE_BINARY'
        echo 'unset PRISMA_SCHEMA_ENGINE_BINARY'
        echoerr "Now using default engine"
    }

    case $1 in
    'use')
        shift
        use $@
        return $?
    ;;
    'unuse')
        shift
        unuse $@
        return $?
    ;;
    *)
        print_usage
        return $?
    ;;
    esac
)

function prisma-engine() {
    eval $(_prisma-engine $@)
}