feat: add logging http api

CHANGELOG.md

@@ -16,6 +16,7 @@ The following emojis are used to highlight certain changes:
 ### Added
 
 - Simple end-to-end test to check that trustless-gateway-domains are set correctly.
+- HTTP API to dynamically list logging subsystems and modify logging levels for subsystems.
 
 ### Changed
 

README.md

@@ -134,6 +134,14 @@ Example cURL commmand to run GC:
 
     curl -v --data '{"BytesToFree": 1099511627776}' http://127.0.0.1:8091/mgr/gc
 
+## Logging
+
+While the logging can be controlled via [environment variable](./docs/environment-variables.md#logging) it is also
+possible to dynamically modify the logging at runtime.
+
+- `http://$RAINBOW_CTL_LISTEN_ADDRESS/mgr/log/level?subsystem=<system name or * for all system>&level=<level>` will set the logging level for a subsystem
+- `http://$RAINBOW_CTL_LISTEN_ADDRESS/mgr/log/ls` will return a comma separated list of available logging subsystems
+
 ## Deployment
 
 Suggested method for self-hosting is to run a [prebuilt Docker image](#docker).

handlers.go

@@ -8,9 +8,11 @@
 	"os"
 	"runtime"
 	"strconv"
+	"strings"
 
 	"github.com/ipfs/boxo/blockstore"
 	leveldb "github.com/ipfs/go-ds-leveldb"
+	"github.com/ipfs/go-log/v2"
 
 	_ "embed"
 	_ "net/http/pprof"
@@ -47,6 +49,29 @@
 	return mux
 }
 
+func addLogHandlers(mux *http.ServeMux) {
+	mux.HandleFunc("/mgr/log/level", func(w http.ResponseWriter, r *http.Request) {
+		defer r.Body.Close()
+
+		q := r.URL.Query()
+		subsystem := q.Get("subsystem")
+		level := q.Get("level")
+
+		if subsystem == "" || level == "" {
+			http.Error(w, "both subsystem and level must be passed", http.StatusBadRequest)
+			return
+		}
+
+		if err := log.SetLogLevel(subsystem, level); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+	mux.HandleFunc("/mgr/log/ls", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte(strings.Join(log.GetSubsystems(), ",")))
+	})
+}
+
 func GCHandler(gnd *Node) func(w http.ResponseWriter, r *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
 		defer r.Body.Close()

main.go

@@ -505,6 +505,7 @@
 
 		apiMux := makeMetricsAndDebuggingHandler()
 		apiMux.HandleFunc("/mgr/gc", GCHandler(gnd))
+		addLogHandlers(apiMux)
 
 		apiSrv := &http.Server{
 			Addr:    ctlListen,