Add support for write_files instructions

lib/tiny-cloud/user-data/alpine-config

@@ -3,25 +3,31 @@
 # shellcheck shell=sh
 
 INIT_ACTIONS_MAIN="$(insert_after set_hostname \
-    "userdata_bootcmd userdata_ntp userdata_apk_cache userdata_apk_repositories userdata_packages" \
+    "userdata_bootcmd userdata_write_files userdata_ntp userdata_apk_cache userdata_apk_repositories userdata_packages" \
     $INIT_ACTIONS_MAIN)"
 INIT_ACTIONS_FINAL="$INIT_ACTIONS_FINAL userdata_runcmd"
 
+get_userdata() {
+    IFS="/"
+    yx -f "$TINY_CLOUD_VAR/user-data" $1 2>/dev/null
+    unset IFS
+}
+
 init__userdata_bootcmd() {
     # run bootcmd
-    local bootcmds="$(imds user-data/bootcmd)"
+    local bootcmds="$(get_userdata bootcmd)"
     for i in $bootcmds; do
-        local cmd="$(imds user-data/bootcmd/"$i")"
+        local cmd="$(get_userdata bootcmd/"$i")"
         sh -c "$cmd"
     done
 }
 
 init__userdata_ntp() {
-    local ntp_enabled="$(imds user-data/ntp/enabled)"
+    local ntp_enabled="$(get_userdata ntp/enabled)"
     if [ "$ntp_enabled" != "yes" ] && [ "$ntp_enabled" != "true" ]; then
         return
     fi
-    local ntp_client="$(imds user-data/ntp/ntp_client)"
+    local ntp_client="$(get_userdata ntp/ntp_client)"
     local svc= pkg=
     case "$ntp_client" in
         busybox)
@@ -46,7 +52,7 @@ init__userdata_ntp() {
 }
 
 init__userdata_apk_cache() {
-    local cache="$(imds user-data/apk/cache)"
+    local cache="$(get_userdata apk/cache)"
     if [ -z "$cache" ]; then
         return
     fi
@@ -60,7 +66,7 @@ init__userdata_apk_cache() {
 }
 
 init__userdata_apk_cache() {
-    local cache="$(imds user-data/apk/cache)"
+    local cache="$(get_userdata apk/cache)"
     if [ -z "$cache" ]; then
         return
     fi
@@ -74,12 +80,12 @@ init__userdata_apk_cache() {
 }
 
 init__userdata_apk_repositories() {
-    local repositories="$(imds user-data/apk/repositories)"
+    local repositories="$(get_userdata apk/repositories)"
     mkdir -p "$ROOT"/etc/apk
     for r in $repositories; do
-        local baseurl="$(imds user-data/apk/repositories/$r/base_url)"
+        local baseurl="$(get_userdata apk/repositories/$r/base_url)"
-        local repos="$(imds user-data/apk/repositories/$r/repos)"
+        local repos="$(get_userdata apk/repositories/$r/repos)"
-        local version="$(imds user-data/apk/repositories/$r/version)"
+        local version="$(get_userdata apk/repositories/$r/version)"
         if [ -z "$version" ]; then
             local version_id=$( . "$ROOT"/etc/os-release 2>/dev/null && echo "$VERSION_ID")
             case "$version_id" in
@@ -91,17 +97,17 @@ init__userdata_apk_repositories() {
             baseurl="${baseurl%/}/$version"
         fi
         for repo in $repos; do
-            local uri="${baseurl%/}/$(imds user-data/apk/repositories/$r/repos/$repo)"
+            local uri="${baseurl%/}/$(get_userdata apk/repositories/$r/repos/$repo)"
             add_once "$ROOT"/etc/apk/repositories "$uri"
         done
     done
 }
 
 init__userdata_packages() {
-    local packages="$(imds user-data/packages)"
+    local packages="$(get_userdata packages)"
     local pkgs=
     for i in $packages; do
-        pkgs="$pkgs $(imds user-data/packages/$i)"
+        pkgs="$pkgs $(get_userdata packages/$i)"
     done
     if [ -n "$pkgs" ]; then
         $MOCK apk add $pkgs
@@ -109,9 +115,69 @@ init__userdata_packages() {
 }
 
 init__userdata_runcmd() {
-	local runcmds="$(imds user-data/runcmd)"
+	local runcmds="$(get_userdata runcmd)"
 	for i in $runcmds; do
-		local cmd="$(imds user-data/runcmd/$i)"
+		local cmd="$(get_userdata runcmd/$i)"
 		sh -c "$cmd"
 	done
 }
+
+# write_file <path> <mode> <owner> <encoding> <append>
+write_file() {
+    # Defaults used are the same as for full cloud-init "spec":
+    # https://cloudinit.readthedocs.io/en/latest/reference/modules.html#write-files
+    local path="$1"
+    local mode="${2:-0644}"
+    local owner="${3:-root:root}"
+    local encoding="${4:-text/plain}"
+    local append="${5:-false}"
+
+    if [ "$append" != "true" ] && [ "$append" != "false" ]; then
+        log err "append must be true or false"
+        return
+    fi
+
+    local tmpfile="$(mktemp $TINY_CLOUD_VAR/user-data.write_files.XXXXXX)"
+
+    case "$encoding" in
+        gzip|gz|gz+base64|gzip+base64|gz+b64|gzip+b64)
+            base64 -d | gzip -d > "$tmpfile"
+            ;;
+        base64|b64)
+            base64 -d > "$tmpfile"
+            ;;
+        text/plain)
+            cat > "$tmpfile"
+            ;;
+    esac
+
+    if [ "$append" = "true" ]; then
+        cat "$tmpfile" >> "$path"
+    else
+        cat "$tmpfile" > "$path"
+    fi
+    rm -f "$tmpfile"
+
+    chmod "$mode" "$path"
+    # mocked as we do not know which users we could use in testing
+    # this way we can check the proper invocation at least
+    $MOCK chown "$owner" "$path"
+}
+
+init__userdata_write_files() {
+    local files="$(get_userdata write_files)"
+
+    for i in $files; do
+        local path="$(get_userdata write_files/$i/path)"
+        if [ -z "$path" ]; then
+            continue
+        fi
+
+        mkdir -p "$(dirname "$ROOT/$path")"
+        get_userdata write_files/$i/content | write_file "$ROOT/$path" \
+            "$(get_userdata write_files/$i/permissions)" \
+            "$(get_userdata write_files/$i/owner)" \
+            "$(get_userdata write_files/$i/encoding)" \
+            "$(get_userdata write_files/$i/append)"
+    done
+}

tests/tiny-cloud-alpine.test

@@ -12,6 +12,7 @@ init_tests \
 	set_network_config_network_interfaces \
 	set_network_config_auto \
 	userdata_bootcmd \
+	userdata_write_files \
 	userdata_ntp \
 	userdata_ntp_busybox \
 	userdata_ntp_openntpd \
@@ -240,3 +241,68 @@ userdata_runcmd_body() {
 		-o match:"^foo$" -o match:"^bar$" \
 		tiny-cloud final
 }
+
+userdata_write_files_body() {
+	fake_userdata_nocloud <<-EOF
+		#alpine-config
+		write_files:
+		- path: /etc/motd
+		  content: |
+		    Hello world
+		- path: /etc/foo
+		  encoding: text/plain
+		  permissions: '0755'
+		  content: |
+		    Hello world
+		- path: /etc/bar
+		  owner: foo:bar
+		  content: |
+		    Hello world
+		- path: /etc/gzipped
+		  encoding: gzip
+		  content: !!binary |
+		    H4sIAAAAAAAAA/NIzcnJVyjPL8pJ4QIA1eA5twwAAAA=
+		- path: /foo/bar/hello
+		  content: |
+		    Hello world
+		- path: /foo/bar/appended
+		  content: |
+		    Hello
+		- path: /foo/bar/appended
+		  append: true
+		  content: |
+		    world
+	EOF
+	# fetch user-data
+	atf_check -e ignore -o ignore tiny-cloud net
+
+	atf_check \
+		-e match:"userdata_write_files: done" \
+		-o match:"chown foo:bar.*etc/bar" \
+		-o match:"chown root:root.*etc/motd" \
+		tiny-cloud main
+
+	if [ "$(cat etc/motd)" != "Hello world" ]; then
+		atf_fail "content of etc/motd was not 'Hello world'"
+	fi
+	# check that etc/motd permissions are the defaults
+	atf_check -o match:"644" stat -c %a etc/motd
+
+	if [ "$(cat etc/foo)" != "Hello world" ]; then
+		atf_fail "content of etc/foo was not 'Hello world'"
+	fi
+	atf_check -o match:"755" stat -c %a etc/foo
+
+	if [ "$(cat etc/gzipped)" != "Hello world" ]; then
+		atf_fail "content of etc/foo was not 'Hello world'"
+	fi
+
+	if [ "$(cat foo/bar/hello)" != "Hello world" ]; then
+		atf_fail "content of foo/bar/hello was not 'Hello world'"
+	fi
+
+	atf_check diff -u foo/bar/appended - <<-EOF
+		Hello
+		world
+	EOF
+}