Accept separate arguments and line continuations in package install scripts

Previously only the first argument was used, so packages passed as separate
arguments were silently skipped. Also disables globbing while splitting and
skips the install when no packages are given.

From #708. Resolved conflicts with the release branch and added a ShellCheck
directive for the intentional word split.

Author: ryanjbonnell

docs/content/docs/8.reference/2.command-reference.md

@@ -24,6 +24,22 @@ This command will detect the operating system and install packages if it is an A
 docker-php-serversideup-dep-install-alpine git
 ```
 
+Packages can be passed as separate arguments, as a comma-separated list, or split across multiple lines with backslash continuations:
+
+```bash [Example - Installing multiple packages on Alpine]
+# Separate arguments
+docker-php-serversideup-dep-install-alpine git zip unzip
+
+# Comma-separated
+docker-php-serversideup-dep-install-alpine "git, zip, unzip"
+
+# Backslash continuations (useful in a Dockerfile)
+docker-php-serversideup-dep-install-alpine \
+    git \
+    zip \
+    unzip
+```
+
 ## docker-php-serversideup-dep-install-debian
 This command will detect the operating system and install packages if it is a Debian based system. This is helpful if you're building multiple operating systems from the same Dockerfile.
 
@@ -32,6 +48,22 @@ This command will detect the operating system and install packages if it is a De
 docker-php-serversideup-dep-install-debian git
 ```
 
+Packages can be passed as separate arguments, as a comma-separated list, or split across multiple lines with backslash continuations:
+
+```bash [Example - Installing multiple packages on Debian]
+# Separate arguments
+docker-php-serversideup-dep-install-debian git zip unzip
+
+# Comma-separated
+docker-php-serversideup-dep-install-debian "git, zip, unzip"
+
+# Backslash continuations (useful in a Dockerfile)
+docker-php-serversideup-dep-install-debian \
+    git \
+    zip \
+    unzip
+```
+
 ## docker-php-serversideup-download
 A build-time helper that downloads a file with retries. Our build matrix starts every image at the same moment, and hosts like GitHub occasionally answer that burst with a `500`. This command retries five times with a short backoff and fails the build if the file never arrives. It's useful in your own Dockerfiles for the same reason.
 

src/common/usr/local/bin/docker-php-serversideup-dep-install-alpine

@@ -3,6 +3,14 @@ set -oe
 
 ###################################################
 # Usage: docker-php-serversideup-dep-install-alpine [alpine-packages]
+#
+# Packages may be passed as separate arguments, comma-delimited, or both:
+#
+#     docker-php-serversideup-dep-install-alpine git, zip
+#
+#     docker-php-serversideup-dep-install-alpine \
+#         git \
+#         zip
 ###################################################
 # This script installs alpine packages that are passed to it
 
@@ -27,20 +35,35 @@ fi
 ############
 # Functions
 ############
+# Accepts any mix of space-separated arguments and comma-delimited lists
+# (e.g. "pkg1, pkg2" or "pkg1 pkg2" or "pkg1 \ pkg2" across lines in a Dockerfile)
 convert_comma_delimited_to_space_separated() {
-    echo $1 | tr ',' ' '
+    printf '%s\n' "$*" | tr ',' ' '
 }
 
 ############
 # Main
 ############
-DEP_PACKAGES=$(convert_comma_delimited_to_space_separated "$@")
+# Re-split into one argument per package. Globbing is disabled so a package
+# name such as "php*" is never expanded against files in the working directory.
+set -f
+# shellcheck disable=SC2046
+set -- $(convert_comma_delimited_to_space_separated "$@")
+set +f
+
+if [ $# -eq 0 ]; then
+    echo "ℹ️ INFO ($script_name): No packages were found in the arguments. Continuing..."
+    exit 0
+fi
+
+# "$*" joins the packages with single spaces for display
+DEP_PACKAGES="$*"
 echo "🤖 Installing: $DEP_PACKAGES"
-apk update 
-apk add --no-cache $DEP_PACKAGES
+apk update
+apk add --no-cache "$@"
 
 
 echo "🧼 Cleaning up installation of: $DEP_PACKAGES"
 rm -rf /var/cache/apk/*
 
-echo "⚡️ Completed installation of: $DEP_PACKAGES"
+echo "⚡️ Completed installation of: $DEP_PACKAGES"

src/common/usr/local/bin/docker-php-serversideup-dep-install-debian

@@ -3,6 +3,14 @@ set -oe
 
 ###################################################
 # Usage: docker-php-serversideup-dep-install-debian [debian-packages]
+#
+# Packages may be passed as separate arguments, comma-delimited, or both:
+#
+#     docker-php-serversideup-dep-install-debian git, zip
+#
+#     docker-php-serversideup-dep-install-debian \
+#         git \
+#         zip
 ###################################################
 # This script installs debian packages that are passed to it
 
@@ -28,17 +36,32 @@ fi
 ############
 # Functions
 ############
+# Accepts any mix of space-separated arguments and comma-delimited lists
+# (e.g. "pkg1, pkg2" or "pkg1 pkg2" or "pkg1 \ pkg2" across lines in a Dockerfile)
 convert_comma_delimited_to_space_separated() {
-    echo $1 | tr ',' ' '
+    printf '%s\n' "$*" | tr ',' ' '
 }
 
 ############
 # Main
 ############
-DEP_PACKAGES=$(convert_comma_delimited_to_space_separated "$@")
+# Re-split into one argument per package. Globbing is disabled so a package
+# name such as "php*" is never expanded against files in the working directory.
+set -f
+# shellcheck disable=SC2046
+set -- $(convert_comma_delimited_to_space_separated "$@")
+set +f
+
+if [ $# -eq 0 ]; then
+    echo "ℹ️ INFO ($script_name): No packages were found in the arguments. Continuing..."
+    exit 0
+fi
+
+# "$*" joins the packages with single spaces for display
+DEP_PACKAGES="$*"
 echo "🤖 Installing: $DEP_PACKAGES"
 apt-get -o Acquire::Retries=3 update
-apt-get -o Acquire::Retries=3 install -y $DEP_PACKAGES
+apt-get -o Acquire::Retries=3 install -y "$@"
 
 
 echo "🧼 Cleaning up installation of: $DEP_PACKAGES"