Supervisor gains proxy ability

Makefile

@@ -162,7 +162,7 @@ server-dev: # Run and restart server for development
 build: frontend system supervisor # Compile all artifacts for production
 
 dev: # Compile, run, and watch all artifacts and server for development
-	$(MAKE_QUIETLY) -j3 frontend-dev system-dev supervisor-dev server-dev
+	$(MAKE_QUIETLY) -j4 frontend-dev system-dev supervisor-dev server-dev
 
 ### Application tools
 

docker/admin/install.bash

@@ -39,6 +39,7 @@ g++
 git
 golang
 htop
+httpie
 jq
 less
 make

docker/runtime/install.bash

@@ -48,7 +48,9 @@ dctrl-tools
 bind9-dnsutils
 less
 git
+golang
 htop
+httpie
 jq
 make
 man

supervisor/compile.bash

@@ -2,6 +2,11 @@
 
 set -euo pipefail
 
+function verbosely {
+    echo "$@"
+    "$@"
+}
+
 cd supervisor
 mkdir -p out
-go build -o out/riju-supervisor ./src
+verbosely go build -o out/riju-supervisor ./src

supervisor/src/main.go

@@ -2,8 +2,75 @@ package main
 
 import (
 	"fmt"
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+	"sync"
 )
 
-func main() {
-	fmt.Println("Hello, world!")
+type supervisor struct {
+	proxyHandler http.Handler
+
+	reloadLock sync.Mutex
+	reloadInProgress bool
+	reloadNeeded bool
+}
+
+func (sv *supervisor) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if strings.HasPrefix(r.URL.Path, "/api/supervisor") {
+		if r.URL.Path == "/api/supervisor/v1/reload" {
+			resp := ""
+			sv.reloadLock.Lock()
+			if !sv.reloadInProgress {
+				sv.reloadInProgress = true
+				go sv.reload()
+				resp = "Triggered reload."
+			} else {
+				sv.reloadNeeded = true
+				resp = "Reload already in progress, scheduling another one."
+			}
+			sv.reloadLock.Unlock()
+			fmt.Fprintln(w, resp)
+			return
+		}
+		http.NotFound(w, r)
+		return
+	}
+	sv.proxyHandler.ServeHTTP(w, r)
+	return
+}
+
+func (sv *supervisor) reloadWithScheduling() {
+	err := sv.reload()
+	if err != nil {
+		log.Printf("failed to reload: %s\n", err.Error())
+	} else {
+		log.Println("successfully reloaded")
+	}
+	sv.reloadLock.Lock()
+	sv.reloadInProgress = false
+	if sv.reloadNeeded {
+		sv.reloadInProgress = true
+		go sv.reloadWithScheduling()
+	}
+	sv.reloadLock.Unlock()
+}
+
+func (sv *supervisor) reload() error {
+	fmt.Println("starting reload")
+	return nil
+}
+
+func main() {
+	url, err := url.Parse("http://localhost:6119")
+	if err != nil {
+		log.Fatal(err)
+	}
+	sv := &supervisor{
+		proxyHandler: httputil.NewSingleHostReverseProxy(url),
+	}
+	log.Println("listening on http://0.0.0.0:80")
+	log.Fatalln(http.ListenAndServe("0.0.0.0:80", sv))
 }