feat: add shared cache setting

src/r-dependent-packages/NOTES.md

@@ -71,6 +71,13 @@ See [the reference of the `pak` package](https://pak.r-lib.org/reference/pak-con
 }
 ```
 
+## Cache directory and cache volume
+
+The package cache directory in the container is set to `/pak/cache`.
+
+This directory is stored in a volume named `devcontainer-pak-cache`
+and is shared among multiple containers.
+
 ## References
 
 - [pak](https://pak.r-lib.org/)

src/r-dependent-packages/devcontainer-feature.json

@@ -53,6 +53,16 @@
 			]
 		}
 	},
+	"containerEnv": {
+		"PKG_PACKAGE_CACHE_DIR": "/pak/cache"
+	},
+	"mounts": [
+		{
+			"source": "devcontainer-pak-cache",
+			"target": "/pak/cache",
+			"type": "volume"
+		}
+	],
 	"onCreateCommand": {
 		"r-dependent-packages": "/usr/local/share/rocker-devcontainer-features/r-dependent-packages/scripts/oncreate.sh"
 	},

src/r-dependent-packages/install.sh

@@ -6,6 +6,8 @@ ROOT=${MANIFESTROOT:-"."}
 REPOS=${ADDITIONALREPOSITORIES:-""}
 DEPS=${DEPENDENCYTYPES:-"all"}
 
+PKG_PACKAGE_CACHE_DIR=${PKG_PACKAGE_CACHE_DIR:-"/pak/cache"}
+
 USERNAME=${USERNAME:-${_REMOTE_USER}}
 
 LIFECYCLE_SCRIPTS_DIR="/usr/local/share/rocker-devcontainer-features/r-dependent-packages/scripts"
@@ -17,6 +19,22 @@ if [ "$(id -u)" -ne 0 ]; then
     exit 1
 fi
 
+create_cache_dir() {
+    if [ -d "$1" ]; then
+        echo "Cache directory $1 already exists. Skip creation..."
+    else
+        echo "Create cache directory $1..."
+        mkdir -p "$1"
+    fi
+
+    if [ -z "$2" ]; then
+        echo "No username provided. Skip chown..."
+    else
+        echo "Change owner of $1 to $2..."
+        chown -R "$2:$2" "$1"
+    fi
+}
+
 check_r() {
     if [ ! -x "$(command -v R)" ]; then
         echo "(!) Cannot run R. Please install R before installing this Feature."
@@ -44,6 +62,8 @@ install_pak() {
 
 export DEBIAN_FRONTEND=noninteractive
 
+create_cache_dir "${PKG_PACKAGE_CACHE_DIR}" "${USERNAME}"
+
 # Set Lifecycle scripts
 mkdir -p "${LIFECYCLE_SCRIPTS_DIR}"
 

src/r-dependent-packages/lifecycle_script.sh

@@ -1,7 +1,24 @@
 #!/usr/bin/env bash
 
+PKG_PACKAGE_CACHE_DIR=${PKG_PACKAGE_CACHE_DIR:-"/pak/cache"}
+
 set -e
 
+fix_permissions() {
+    local dir
+    dir="${1}"
+
+    if [ ! -w "${dir}" ]; then
+        echo "Fixing permissions of '${dir}'..."
+        sudo chown -R "$(id -u):$(id -g)" "${dir}"
+        echo "Done!"
+    else
+        echo "Permissions of '${dir}' are OK!"
+    fi
+}
+
+fix_permissions "${PKG_PACKAGE_CACHE_DIR}"
+
 echo "Install dependent R packages..."
 
 R -q -e \