chore(cmd): clean up commands (#9705)

Move infrastructure related commands to under `cmd/infra` and
development stuff to `cmd/dev`. The default build command builds the
regular user facing binaries: syncthing, stdiscosrv, and strelaysrv.

cmd/infra/stcrashreceiver/stcrashreceiver.go

@@ -0,0 +1,133 @@
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"io"
+	"log"
+	"net/http"
+	"path"
+	"strings"
+	"sync"
+)
+
+type crashReceiver struct {
+	store  *diskStore
+	sentry *sentryService
+	ignore *ignorePatterns
+
+	ignoredMut sync.RWMutex
+	ignored    map[string]struct{}
+}
+
+func (r *crashReceiver) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	// The final path component should be a SHA256 hash in hex, so 64 hex
+	// characters. We don't care about case on the request but use lower
+	// case internally.
+	reportID := strings.ToLower(path.Base(req.URL.Path))
+	if len(reportID) != 64 {
+		http.Error(w, "Bad request", http.StatusBadRequest)
+		return
+	}
+	for _, c := range reportID {
+		if c >= 'a' && c <= 'f' {
+			continue
+		}
+		if c >= '0' && c <= '9' {
+			continue
+		}
+		http.Error(w, "Bad request", http.StatusBadRequest)
+		return
+	}
+
+	switch req.Method {
+	case http.MethodGet:
+		r.serveGet(reportID, w, req)
+	case http.MethodHead:
+		r.serveHead(reportID, w, req)
+	case http.MethodPut:
+		r.servePut(reportID, w, req)
+	default:
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+// serveGet responds to GET requests by serving the uncompressed report.
+func (r *crashReceiver) serveGet(reportID string, w http.ResponseWriter, _ *http.Request) {
+	bs, err := r.store.Get(reportID)
+	if err != nil {
+		http.Error(w, "Not found", http.StatusNotFound)
+		return
+	}
+	w.Write(bs)
+}
+
+// serveHead responds to HEAD requests by checking if the named report
+// already exists in the system.
+func (r *crashReceiver) serveHead(reportID string, w http.ResponseWriter, _ *http.Request) {
+	r.ignoredMut.RLock()
+	_, ignored := r.ignored[reportID]
+	r.ignoredMut.RUnlock()
+	if ignored {
+		return // found
+	}
+	if !r.store.Exists(reportID) {
+		http.Error(w, "Not found", http.StatusNotFound)
+	}
+}
+
+// servePut accepts and stores the given report.
+func (r *crashReceiver) servePut(reportID string, w http.ResponseWriter, req *http.Request) {
+	result := "receive_failure"
+	defer func() {
+		metricCrashReportsTotal.WithLabelValues(result).Inc()
+	}()
+
+	r.ignoredMut.RLock()
+	_, ignored := r.ignored[reportID]
+	r.ignoredMut.RUnlock()
+	if ignored {
+		result = "ignored_cached"
+		io.Copy(io.Discard, req.Body)
+		return // found
+	}
+
+	// Read at most maxRequestSize of report data.
+	log.Println("Receiving report", reportID)
+	lr := io.LimitReader(req.Body, maxRequestSize)
+	bs, err := io.ReadAll(lr)
+	if err != nil {
+		log.Println("Reading report:", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	if r.ignore.match(bs) {
+		r.ignoredMut.Lock()
+		if r.ignored == nil {
+			r.ignored = make(map[string]struct{})
+		}
+		r.ignored[reportID] = struct{}{}
+		r.ignoredMut.Unlock()
+		result = "ignored"
+		return
+	}
+
+	result = "success"
+
+	// Store the report
+	if !r.store.Put(reportID, bs) {
+		log.Println("Failed to store report (queue full):", reportID)
+		result = "queue_failure"
+	}
+
+	// Send the report to Sentry
+	if !r.sentry.Send(reportID, userIDFor(req), bs) {
+		log.Println("Failed to send report to sentry (queue full):", reportID)
+		result = "sentry_failure"
+	}
+}