smelter: Add build system management script

This commit adds smelter, a script for managing the individual
components of the foundry build system.
Once complete, smelter will act as a process watchdog and monitor
the state of the various IPC endpoints and pubsub topics that are
used by the buildsystem.

diff --git a/smelter.sh b/smelter.sh
new file mode 100644 (file)
index 0000000..6ea9063
--- /dev/null
+++ b/smelter.sh
@@ -0,0 +1,154 @@
+#!/bin/bash
+
+topics=("commits")
+endpoints=()
+processes=()
+
+monitor_endpoints() {
+       local endpoints=("$@")
+
+       while inst_running; do
+               sleep 5
+       done
+
+       return 0
+}
+
+watch_endpoints() {
+       local endpoints=("$@")
+
+       local endpoint
+
+       # This function starts the monitor that watches all endpoints in the
+       # build system. Because this function is executed before the other
+       # components of the build system are started, endpoints are likely not
+       # to exist. Hence, we also make sure to create all endpoints here.
+
+       for endpoint in "${endpoints[@]}"; do
+               if ! ipc_endpoint_open "$endpoint" > /dev/null; then
+                       log_error "Could not open endpoint $endpoint"
+                       return 1
+               fi
+       done
+
+       if ! monitor_endpoints "${endpoints[@]}" &; then
+               return 1
+       fi
+
+       return 0
+}
+
+process_is_running() {
+       local process="$1"
+
+       return 0
+}
+
+process_start() {
+       local process="$1"
+
+       return 0
+}
+
+process_watchdog() {
+       local processes=("$@")
+
+       local process
+
+       while inst_running; do
+               for process in "${processes[@]}"; do
+                       if process_is_running "$process"; then
+                               continue
+                       fi
+
+                       if ! process_start "$process"; then
+                               log_error "Could not start $process"
+                       fi
+               done
+
+               sleep 5
+       done
+
+       return 0
+}
+
+watch_processes() {
+       local processes=("$@")
+
+       if ! process_watchdog "${processes[@]}" &; then
+               return 1
+       fi
+
+       return 0
+}
+
+handle_message() {
+       local endpoint="$1"
+       local msg="$2"
+
+       return 1
+}
+
+smelter_run() {
+       local endpoint
+       local topic
+
+       if ! endpoint=$(ipc_endpoint_open "pub/foundry"); then
+               log_error "Could not listen on pub/foundry"
+               return 1
+       fi
+
+       for topic in "${topics[@]}"; do
+               if ! ipc_endpoint_subscribe "$endpoint" "$topic"; then
+                       log_error "Could not subscribe to $topic"
+                       return 1
+               fi
+       done
+
+       if ! watch_endpoints "${endpoints[@]}"; then
+               log_error "Couldn't start endpoint monitor"
+               return 1
+       fi
+
+       if ! watch_processes "${processes[@]}"; then
+               log_error "Couldn't start process monitor"
+               return 1
+       fi
+
+       while inst_running; do
+               local msg
+
+               if ! msg=$(ipc_endpoint_recv "$endpoint" 5); then
+                       continue
+               fi
+
+               handle_message "$endpoint" "$msg"
+       done
+
+       return 0
+}
+
+main() {
+       if ! opt_parse "$@"; then
+               return 1
+       fi
+
+       if ! inst_singleton smelter_run; then
+               return 1
+       fi
+
+       return 0
+}
+
+{
+       if ! . toolbox.sh; then
+               exit 1
+       fi
+
+       if ! include "log" "opt" "inst" "ipc" "foundry/msg"; then
+               exit 1
+       fi
+
+       main "$@"
+       exit "$?"
+}