support additional configuration yml files via configuration directory

Files in configuration directory EXTRA_CONFIG_DIR (being
/etc/ngcp-config/config.d/ by default) with the suffix yml (so
e.g. a file named pbx.yml can be shipped by an external Debian
package) are additionally taken into consideration as main
configuration files.

Those extra configuration file(s) have higher precedence than
the other yml configuration files (config.yml, network.yml,...),
*except* for constants.yml which has the power to override all
settings, including the ones from files inside EXTRA_CONFIG_DIR.

Closes: sipwise-#3059

docs/ngcpcfg.txt

@@ -71,6 +71,12 @@ provides global variables used inside ngcpcfg and its helper scripts. This file
 is *not* supposed to be modified by the user (without having a very good
 reason).
 
+* _/etc/ngcp-config/config.d/_: optional configuration directory with additional
+yml configuration files. Files inside this directory aren't supposed to be
+added or modified by the user. The purpose of this configuration directory is
+that software packages can enable/disable certain features through configuration
+options on demand.
+
 * _/etc/ngcp-config/ngcpcfg.d/_: configuration directory for ngcpcfg itself.
 Files with suffix '.cfg' inside this directory are sourced after
 /etc/ngcp-config/ngcpcfg.cfg has been read. Files inside this directory are
@@ -78,7 +84,8 @@ Files with suffix '.cfg' inside this directory are sourced after
 
 [IMPORTANT]
 Configuration file priority: constants.yml takes precedence over
-config.local.yml, over config.$HOSTNAME.yml, over config.yml.
+all files in _/etc/ngcp-config/config.d/_, over config.local.yml,
+over config.$HOSTNAME.yml, over config.yml.
 
 High Availability setup specific configuration files
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

etc/ngcp-config/ngcpcfg.cfg

@@ -9,6 +9,7 @@ HOST_CONFIG="${NGCPCTL_MAIN}/config.$(hostname).yml"
 LOCAL_CONFIG="${NGCPCTL_MAIN}/config.local.yml"
 CONSTANTS_CONFIG="${NGCPCTL_MAIN}/constants.yml"
 NETWORK_CONFIG="${NGCPCTL_MAIN}/network.yml"
+EXTRA_CONFIG_DIR="${NGCPCTL_MAIN}/config.d/"
 
 # configuration files that should be managed
 CONFIG_POOL='/etc'

functions/main

@@ -79,6 +79,12 @@ if ! [ -d "$TEMPLATE_POOL" ] ; then
   log_error "No template directory (${TEMPLATE_POOL}) found - exiting."
   exit 1
 fi
+
+if [ -d "${EXTRA_CONFIG_DIR:-}" ] && ls ${EXTRA_CONFIG_DIR}/*.yml &>/dev/null ; then
+  log_debug "EXTRA_CONFIG_DIR is configured and *.yml files are present, setting EXTRA_CONFIG_FILES"
+  EXTRA_CONFIG_FILES=${EXTRA_CONFIG_DIR}/*.yml
+fi
+
 ## }}}
 
 ## environment variables {{{
@@ -99,6 +105,8 @@ export LOCAL_CONFIG
 export NGCPCTL_CONFIG
 export CONSTANTS_CONFIG
 export NETWORK_CONFIG
+export EXTRA_CONFIG_DIR
+export EXTRA_CONFIG_FILES
 ## }}}
 
 ## HA / carrier features {{{

helper/build_config

@@ -67,8 +67,8 @@ umask 0077
 TT_WRAPPER="${HELPER}/tt2-wrapper"
 
 log_debug "Output file ${output_file} based on ${input_file}"
-log_debug "Executing: $TT_WRAPPER ${input_file} ${host_conf:-} ${local_conf:-} $NGCPCTL_CONFIG ${NETWORK_CONFIG:-} $CONSTANTS_CONFIG > ${output_file}"
+log_debug "Executing: $TT_WRAPPER ${input_file} ${host_conf:-} ${local_conf:-} $NGCPCTL_CONFIG ${NETWORK_CONFIG:-} ${EXTRA_CONFIG_FILES:-} $CONSTANTS_CONFIG > ${output_file}"
-if "$TT_WRAPPER" "${input_file}" ${host_conf:-} ${local_conf:-} "$NGCPCTL_CONFIG" "${NETWORK_CONFIG:-}" "$CONSTANTS_CONFIG" > "${output_file}" 2>/dev/null ; then
+if "$TT_WRAPPER" "${input_file}" ${host_conf:-} ${local_conf:-} "$NGCPCTL_CONFIG" "${NETWORK_CONFIG:-}" ${EXTRA_CONFIG_FILES:-} "$CONSTANTS_CONFIG" > "${output_file}" 2>/dev/null ; then
   log_info "Generating ${output_file}: OK"
   RC=0
 else
@@ -76,7 +76,7 @@ else
   RC=1
 
   log_info "NOTE: Check those files for valid syntax and encoding:"
-  for f in "${input_file}" ${host_conf:-} ${local_conf:-} "$NGCPCTL_CONFIG" "${NETWORK_CONFIG:-}" "$CONSTANTS_CONFIG" ; do
+  for f in "${input_file}" ${host_conf:-} ${local_conf:-} "$NGCPCTL_CONFIG" "${NETWORK_CONFIG:-}" ${EXTRA_CONFIG_FILES:-} "$CONSTANTS_CONFIG" ; do
     [ -r "$f" ] && log_info "$f"
   done
   log_info "Running /usr/share/ngcp-ngcpcfg/helper/tt2-wrapper <file> should provide more details."

scripts/build

@@ -30,7 +30,7 @@ if [ -n "${1:-}" ] ; then
 fi
 
 # make sure encoding is OK
-for f in ${NGCPCTL_CONFIG:-} ${HOST_CONFIG:-} ${LOCAL_CONFIG:-} ${NETWORK_CONFIG:-} ${CONSTANTS_CONFIG:-} ; do
+for f in ${NGCPCTL_CONFIG:-} ${HOST_CONFIG:-} ${LOCAL_CONFIG:-} ${NETWORK_CONFIG:-} ${EXTRA_CONFIG_FILES:-} ${CONSTANTS_CONFIG:-} ; do
   if [ -r "$f" ] && ! file "$f" | grep -qe "UTF-8" -qe "ASCII" ; then
     log_error "Encoding check of ${f} fails: neither ASCII nor UTF-8."
     log_error "Please convert ${f} to UTF-8."
@@ -45,7 +45,7 @@ for f in ${NGCPCTL_CONFIG:-} ${HOST_CONFIG:-} ${LOCAL_CONFIG:-} ${NETWORK_CONFIG
 done
 
 # check for valid YAML syntax
-for f in ${NGCPCTL_CONFIG:-} ${HOST_CONFIG:-} ${LOCAL_CONFIG:-} ${NETWORK_CONFIG:-} ${CONSTANTS_CONFIG:-} ; do
+for f in ${NGCPCTL_CONFIG:-} ${HOST_CONFIG:-} ${LOCAL_CONFIG:-} ${NETWORK_CONFIG:-} ${EXTRA_CONFIG_FILES:-} ${CONSTANTS_CONFIG:-} ; do
   if [ -r "$f" ] ; then
     # use YAML::Tiny for checking
     log_debug "Validating main YAML syntax of ${f}"
@@ -78,13 +78,30 @@ else
     exit 0
   fi
 
+  trigger_rebuild=false
+
+  if [ -n "${EXTRA_CONFIG_FILES:-}" ] ; then
+    for file in $EXTRA_CONFIG_FILES ; do
+      if git diff-index --name-only HEAD | grep -qe "$(basename $file)" ; then
+	log_debug "modification in EXTRA_CONFIG_FILES file $file found"
+        trigger_rebuild=true
+        break # no reason for further checks
+      fi
+    done
+  fi
+
   if git diff-index --name-only HEAD | grep \
          -qe "$(basename $NGCPCTL_CONFIG)" \
          -qe "$(basename $HOST_CONFIG)" \
          -qe "$(basename $LOCAL_CONFIG)" \
          -qe "$(basename $NETWORK_CONFIG)" \
          -qe "$(basename $CONSTANTS_CONFIG)" ; then
-     log_info "Main configuation files has been changed, running full rebuild."
+    log_debug "modification in main configuration file found"
+    trigger_rebuild=true
+  fi
+
+  if $trigger_rebuild ; then
+    log_info "Main configuation file(s) has been changed, running full rebuild."
     log_debug "Executing: build_config_files $*"
     build_config_files "$*"
   fi