Allow to add additional apk keys

Resolves #1

README.adoc

@@ -67,6 +67,12 @@ Alpine branch (aka release) to install: `vMAJOR.MINOR`, `latest-stable`, or `edg
 Example: `{alpine-latest}` +
 Default: `latest-stable`
 
+extra-keys::
+A list of paths of additional trusted keys (for installing packages from the _extra-repositories_) to copy into _/etc/apk/keys/_.
+The paths should be relative to the workspace directory (the default location of your repository when using the checkout action).
++
+Example: `.keys/pkgs@example.org-56d0d9fd.rsa.pub`
+
 extra-repositories::
 A list of additional Alpine repositories to add into _/etc/apk/repositories_ (Alpine’s official _main_ and _community_ repositories are always added).
 +

action.yml

@@ -24,6 +24,13 @@ inputs:
     description: Alpine branch (aka release) to install (e.g. `v3.15`, `latest-stable`, `edge`).
     required: false
     default: latest-stable
+  extra-keys:
+    description: >
+      A list of paths of additional trusted keys (for installing packages from the
+      extra-repositories) to copy into /etc/apk/keys/. The paths should be relative to the
+      workspace directory (the default location of your repository when using the checkout action).
+    required: false
+    default: ''
   extra-repositories:
     description: >
       A list of additional Alpine repositories to add into /etc/apk/repositories (Alpine's official
@@ -71,6 +78,7 @@ runs:
         INPUT_APK_TOOLS_URL: ${{ inputs.apk-tools-url }}
         INPUT_ARCH: ${{ inputs.arch }}
         INPUT_BRANCH: ${{ inputs.branch }}
+        INPUT_EXTRA_KEYS: ${{ inputs.extra-keys }}
         INPUT_EXTRA_REPOSITORIES: ${{ inputs.extra-repositories }}
         INPUT_MIRROR_URL: ${{ inputs.mirror-url }}
         INPUT_PACKAGES: ${{ inputs.packages }}

setup-alpine.sh

@@ -5,6 +5,7 @@
 # - INPUT_APK_TOOLS_URL
 # - INPUT_ARCH
 # - INPUT_BRANCH
+# - INPUT_EXTRA_KEYS
 # - INPUT_EXTRA_REPOSITORIES
 # - INPUT_MIRROR_URL
 # - INPUT_PACKAGES
@@ -137,6 +138,13 @@ case "$INPUT_BRANCH" in
 	       "Expected 'v[0-9].[0-9]+' (e.g. v3.15), edge, or latest-stable, but got: $INPUT_BRANCH."
 esac
 
+for path in $INPUT_EXTRA_KEYS; do
+	if ! [ -r "$GITHUB_WORKSPACE/$path" ]; then
+		die 'Invalid input parameter: extra-keys' \
+		    "File does not exist in workspace or is not readable: $path."
+	fi
+done
+
 if ! expr "$INPUT_SHELL_NAME" : [a-zA-Z][a-zA-Z0-9_.~+@%-]*$ >/dev/null; then
 	die 'Invalid input parameter: shell-name' \
 	    "Expected value matching regex ^[a-zA-Z][a-zA-Z0-9_.~+@%-]*$, but got: $INPUT_SHELL_NAME."
@@ -216,6 +224,11 @@ printf '%s\n' \
 	| tee etc/apk/repositories
 
 cp -r "$SCRIPT_DIR"/keys etc/apk/
+
+for path in $INPUT_EXTRA_KEYS; do
+	cp "$GITHUB_WORKSPACE/$path" etc/apk/keys/
+done
+
 cat /etc/resolv.conf > etc/resolv.conf
 
 info "Installing base packages into $(pwd)"