nginx: normalize installation (docs and script)s over all distros

This is the revision of the documentation about the varous nginx installation
variants.  It also implements the nginx installation scripts for morty and
filtron.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

utils/lib.sh

@@ -138,6 +138,16 @@ rst_para() {
     fi
 }
 
+die() {
+    echo -e "${_BRed}ERROR:${_creset} ${BASH_SOURCE[1]}: line ${BASH_LINENO[0]}: ${2-died ${1-1}}" >&2;
+    exit "${1-1}"
+}
+
+die_caller() {
+    echo -e "${_BRed}ERROR:${_creset} ${BASH_SOURCE[2]}: line ${BASH_LINENO[1]}: ${FUNCNAME[1]}(): ${2-died ${1-1}}" >&2;
+    exit "${1-1}"
+}
+
 err_msg()  { echo -e "${_BRed}ERROR:${_creset} $*" >&2; }
 warn_msg() { echo -e "${_BBlue}WARN:${_creset}  $*" >&2; }
 info_msg() { echo -e "${_BYellow}INFO:${_creset}  $*" >&2; }
@@ -471,11 +481,7 @@ service_is_available() {
 
     # usage:  service_is_available <URL>
 
-    local URL="$1"
-    if [[ -z $URL ]]; then
-        err_msg "service_is_available: missing arguments"
-        return 42
-    fi
+    [[ -z $1 ]] && die_caller 42 "missing argument <URL>"
 
     http_code=$(curl -H 'Cache-Control: no-cache' \
          --silent -o /dev/null --head --write-out '%{http_code}' --insecure \
@@ -624,6 +630,175 @@ EOF
 }
 
 
+# nginx
+# -----
+
+nginx_distro_setup() {
+    # shellcheck disable=SC2034
+
+    NGINX_DEFAULT_SERVER=/etc/nginx/nginx.conf
+
+    # Including *location* directives from a dedicated config-folder into the
+    # server directive is, what what fedora (already) does.
+    NGINX_APPS_ENABLED="/etc/nginx/default.d"
+
+    # We add a apps-available folder and linking configurations into the
+    # NGINX_APPS_ENABLED folder.  See also nginx_include_apps_enabled().
+    NGINX_APPS_AVAILABLE="/etc/nginx/default.apps-available"
+
+    case $DIST_ID-$DIST_VERS in
+        ubuntu-*|debian-*)
+            NGINX_PACKAGES="nginx"
+            NGINX_DEFAULT_SERVER=/etc/nginx/sites-available/default
+            ;;
+        arch-*)
+            NGINX_PACKAGES="nginx-mainline"
+            ;;
+        fedora-*)
+            NGINX_PACKAGES="nginx"
+            ;;
+        *)
+            err_msg "$DIST_ID-$DIST_VERS: nginx not yet implemented"
+            ;;
+    esac
+}
+nginx_distro_setup
+
+install_nginx(){
+    info_msg "installing nginx ..."
+    pkg_install "${NGINX_PACKAGES}"
+    case $DIST_ID-$DIST_VERS in
+        arch-*|fedora-*)
+            systemctl enable nginx
+            systemctl start nginx
+            ;;
+    esac
+}
+
+nginx_is_installed() {
+    command -v nginx &>/dev/null
+}
+
+nginx_reload() {
+
+    info_msg "reload nginx .."
+    echo
+    if ! nginx -t; then
+       err_msg "testing nginx configuration failed"
+       return 42
+    fi
+    systemctl restart nginx
+}
+
+nginx_install_app() {
+
+    # usage:  nginx_install_app [<template option> ...] <myapp>
+    #
+    # <template option>:   see install_template
+
+    local template_opts=()
+    local pos_args=("$0")
+
+    for i in "$@"; do
+        case $i in
+            -*) template_opts+=("$i");;
+            *)  pos_args+=("$i");;
+        esac
+    done
+
+    nginx_include_apps_enabled "${NGINX_DEFAULT_SERVER}"
+
+    install_template "${template_opts[@]}" \
+                     "${NGINX_APPS_AVAILABLE}/${pos_args[1]}" \
+                     root root 644
+    nginx_enable_app "${pos_args[1]}"
+    info_msg "installed nginx app: ${pos_args[1]}"
+}
+
+nginx_include_apps_enabled() {
+
+    # Add the *NGINX_APPS_ENABLED* infrastruture to a nginx server block.  Such
+    # infrastruture is already known from fedora, including apps (location
+    # directives) from the /etc/nginx/default.d folder into the *default* nginx
+    # server.
+
+    # usage: nginx_include_apps_enabled <config-file>
+    #
+    #   config-file: Config file with server directive in.
+
+    [[ -z $1 ]] && die_caller 42 "missing argument <config-file>"
+    local server_conf="$1"
+
+    # include /etc/nginx/default.d/*.conf;
+    local include_directive="include ${NGINX_APPS_ENABLED}/*.conf;"
+    local include_directive_re="^\s*include ${NGINX_APPS_ENABLED}/\*\.conf;"
+
+    info_msg "checking existence: '${include_directive}' in file  ${server_conf}"
+    if grep "${include_directive_re}" "${server_conf}"; then
+        info_msg "OK, already exists."
+        return
+    fi
+
+    info_msg "add missing directive: '${include_directive}'"
+    cp "${server_conf}" "${server_conf}.bak"
+
+    (
+        local line
+        local stage=0
+        while IFS=  read -r line
+        do
+            echo "$line"
+            if [[ $stage = 0 ]]; then
+                if [[ $line =~ ^[[:space:]]*server*[[:space:]]*\{ ]]; then
+                    stage=1
+                fi
+            fi
+
+            if [[ $stage = 1 ]]; then
+                echo "        # Load configuration files for the default server block."
+                echo "        $include_directive"
+                echo ""
+                stage=2
+            fi
+        done < "${server_conf}.bak"
+    ) > "${server_conf}"
+
+}
+
+nginx_remove_app() {
+
+    # usage:  nginx_remove_app <myapp.conf>
+
+    info_msg "remove nginx app: $1"
+    nginx_dissable_app "$1"
+    rm -f "${NGINX_APPS_AVAILABLE}/$1"
+}
+
+nginx_enable_app() {
+
+    # usage:  nginx_enable_app <myapp.conf>
+
+    local CONF="$1"
+
+    info_msg "enable nginx app: ${CONF}"
+    mkdir -p "${NGINX_APPS_ENABLED}"
+    rm -f "${NGINX_APPS_ENABLED}/${CONF}"
+    ln -s "${NGINX_APPS_AVAILABLE}/${CONF}" "${NGINX_APPS_ENABLED}/${CONF}"
+    nginx_reload
+}
+
+nginx_dissable_app() {
+
+    # usage:  nginx_disable_app <myapp.conf>
+
+    local CONF="$1"
+
+    info_msg "disable nginx app: ${CONF}"
+    rm -f "${NGINX_APPS_ENABLED}/${CONF}"
+    nginx_reload
+}
+
+
 # Apache
 # ------