Allow customizing the path to the package to deploy (#82)

README.md

@@ -26,8 +26,9 @@ You can also add it to upcoming builds of an existing application:
 $ heroku buildpacks:set vapor/vapor
 ```
 
-The buildpack will detect your app as Swift if it has a `Package.swift` file in
-the root.
+The buildpack will detect your app as Swift if it has a `Package.swift` file in the
+repository. You can customize the path for the Swift package to deploy by setting the
+`PACKAGE_DIR` config setting.
 
 ### Procfile
 
@@ -51,7 +52,8 @@ web: Run --env=production --port=$PORT
 
 The buildpack defaults to Swift 6.0.2, but is compatible with Swift 5.9.1 - 6.0.1.
 
-If you need to use a specific older version of the Swift toolchain from this range, you can pin the version number using a file called `.swift-version` in the root of the project folder, or by setting a `SWIFT_VERSION` configuration variable on Heroku, then deploying again. 
+If you need to use a specific older version of the Swift toolchain from this range, you can pin the version number using a file called `.swift-version` in the root of the project folder (or at the configured `PACKAGE_DIR` setting), or by
+setting a `SWIFT_VERSION` configuration variable on Heroku, then deploying again.
 
 ```shell
 $ echo '5.10.1' > .swift-version
@@ -147,12 +149,12 @@ Save the script as `bin/pre_compile` in the root of your project.
     GIT_PRIVATE_DOMAIN=`cat $ENV_DIR/GIT_PRIVATE_DOMAIN | tr -d '[[:space:]]'`
     GIT_PRIVATE_USER=`cat $ENV_DIR/GIT_PRIVATE_USER | tr -d '[[:space:]]'`
     GIT_PRIVATE_PASSWORD=`cat $ENV_DIR/GIT_PRIVATE_PASSWORD | tr -d '[[:space:]]'`
-    
+
     # Create .netrc file with credentials
     echo "machine $GIT_PRIVATE_DOMAIN" >> "$HOME/.netrc"
     echo "login $GIT_PRIVATE_USER" >> "$HOME/.netrc"
     echo "password $GIT_PRIVATE_PASSWORD" >> "$HOME/.netrc"
-    
+
     # Create cleanup script so the dyno does not see these values at runtime
     mkdir -p "$BUILD_DIR/.profile.d"
     echo "unset GIT_PRIVATE_DOMAIN" >> "$BUILD_DIR/.profile.d/netrc.sh"

bin/compile

@@ -7,10 +7,21 @@ set -o pipefail
 BIN_DIR=$(cd $(dirname $0); pwd)
 ROOT_DIR=$(dirname $BIN_DIR)
 
-BUILD_DIR=$1
+APP_DIR=$1
 CACHE_DIR=$2
 ENV_DIR=$3
 
+VAR_PATH="$ENV_DIR/PACKAGE_DIR"
+
+if [[ -f "$VAR_PATH" ]]; then
+  package=$(cat "$VAR_PATH")
+  BUILD_DIR="$APP_DIR/$package"
+  echo "Using package directory at $package"
+else
+  BUILD_DIR="$APP_DIR"
+  echo "No PACKAGE_DIR config variable is set. Using the repo root."
+fi
+
 SWIFT_VERSION="6.0.2"
 SWIFT_BUILD_CONFIGURATION="release"
 SWIFT_BUILD_FLAGS=""
@@ -19,8 +30,11 @@ source "/etc/lsb-release"
 source "$BIN_DIR/utils"
 
 if [ -f "$BUILD_DIR/.swift-version" ]; then
-  SWIFT_VERSION=`cat $BUILD_DIR/.swift-version | tr -d '[[:space:]]'`
-  puts-step "Using Swift $SWIFT_VERSION (from .swift-version file)"
+  SWIFT_VERSION=$(cat $BUILD_DIR/.swift-version | tr -d '[[:space:]]')
+  puts-step "Using Swift $SWIFT_VERSION (from package .swift-version file)"
+elif [ -f "$APP_DIR/.swift-version" ]; then
+  SWIFT_VERSION=$(cat $APP_DIR/.swift-version | tr -d '[[:space:]]')
+  puts-step "Using Swift $SWIFT_VERSION (from top-level .swift-version file)"
 elif [ -f "$ENV_DIR/SWIFT_VERSION" ]; then
   SWIFT_VERSION=`cat $ENV_DIR/SWIFT_VERSION | tr -d '[[:space:]]'`
   puts-step "Using Swift $SWIFT_VERSION (from SWIFT_VERSION config)"
@@ -58,8 +72,13 @@ if [[ -z "$RUN_TESTS" ]]; then
 fi
 
 # Setup application environment
-mkdir -p $BUILD_DIR/.profile.d
+set-env() {
+  PROFILE_PATH="$APP_DIR/.profile.d/swift.sh"
+  echo "export $1=$2" >>$PROFILE_PATH
+}
+
+mkdir -p $APP_DIR/.profile.d
 
-set-env PATH '$HOME/.swift-bin:$PATH'
-set-env LD_LIBRARY_PATH '$LD_LIBRARY_PATH:$HOME/.swift-lib'
+set-env PATH '$HOME/$APP_DIR/.swift-bin:$PATH'
+set-env LD_LIBRARY_PATH "$LD_LIBRARY_PATH:$HOME/.swift-lib:$APP_DIR/.swift-lib"
 set-env SWIFT_BACKTRACE "enable=yes,sanitize=yes,threads=all,images=all,interactive=no,output-to=stderr,symbolicate=fast,swift-backtrace=.swift-bin/$SWIFT_BACKTRACE_EXECUTABLE"

bin/detect

@@ -1,7 +1,12 @@
 #!/usr/bin/env bash
 # bin/detect <build-dir>
 
-if [[ -f $1/Package.swift ]]; then
+BUILD_DIR=$1
+
+MANIFEST='Package.swift'
+RESULTS=$(find "$BUILD_DIR" -name $MANIFEST)
+
+if [[ "$RESULTS" == *"$MANIFEST"* ]]; then
   echo "Swift" && exit 0
 else
   echo "no" && exit 1

bin/steps/swift-install

@@ -2,20 +2,20 @@ DYNAMIC_LIBRARY_REGEX=".*\.so\(\.[0-9]+\)*\'"
 SWIFT_PREFIX="$(swiftenv prefix)"
 
 puts-step "Installing dynamic libraries"
-mkdir -p $BUILD_DIR/.swift-lib
-find -L .build/$SWIFT_BUILD_CONFIGURATION -regex "$DYNAMIC_LIBRARY_REGEX" -type f -exec cp -a {} $BUILD_DIR/.swift-lib \; || true 2>/dev/null
+mkdir -p $APP_DIR/.swift-lib
+find -L .build/$SWIFT_BUILD_CONFIGURATION -regex "$DYNAMIC_LIBRARY_REGEX" -type f -exec cp -a {} $APP_DIR/.swift-lib \; || true 2>/dev/null
 
 if [ ! -z "$SWIFT_DYNAMIC_STDLIB" ]; then
-  find -L $SWIFT_PREFIX/usr/lib/swift/linux -regex "$DYNAMIC_LIBRARY_REGEX" -type f -exec cp -a {} $BUILD_DIR/.swift-lib \; || true 2>/dev/null
+  find -L $SWIFT_PREFIX/usr/lib/swift/linux -regex "$DYNAMIC_LIBRARY_REGEX" -type f -exec cp -a {} $APP_DIR/.swift-lib \; || true 2>/dev/null
 fi
 
 puts-step "Installing binaries"
-mkdir -p $BUILD_DIR/.swift-bin
-find -L .build/$SWIFT_BUILD_CONFIGURATION ! -regex "$DYNAMIC_LIBRARY_REGEX" -type f -perm /a+x -exec cp -a {} $BUILD_DIR/.swift-bin \; || true 2>/dev/null
-cp -a $SWIFT_PREFIX/usr/libexec/swift/linux/$SWIFT_BACKTRACE_EXECUTABLE $BUILD_DIR/.swift-bin
+mkdir -p $APP_DIR/.swift-bin
+find -L .build/$SWIFT_BUILD_CONFIGURATION ! -regex "$DYNAMIC_LIBRARY_REGEX" -type f -perm /a+x -exec cp -a {} $APP_DIR/.swift-bin \; || true 2>/dev/null
+cp -a $SWIFT_PREFIX/usr/libexec/swift/linux/$SWIFT_BACKTRACE_EXECUTABLE $APP_DIR/.swift-bin
 
 puts-step "Installing resources"
-find -L .build/$SWIFT_BUILD_CONFIGURATION/* -regex '.*\.resources$' -exec cp -a {} $BUILD_DIR/.swift-bin \; || true 2>/dev/null
+find -L .build/$SWIFT_BUILD_CONFIGURATION/* -regex '.*\.resources$' -exec cp -a {} $APP_DIR/.swift-bin \; || true 2>/dev/null
 
 puts-step "Cleaning up after build"
 rm -rf .build

bin/utils

@@ -1,8 +1,3 @@
 puts-step() {
   echo "-----> $@"
 }
-
-set-env() {
-  PROFILE_PATH="$BUILD_DIR/.profile.d/swift.sh"
-  echo "export $1=$2" >> $PROFILE_PATH
-}