Enable sentry reporting. (#180)

This commit adds basic sentry reporting. If enabled by setting the
appropriate configuration value, it will report panics and errors.
Certain functions in the core package (Delegate, Encrypt, Decrypt,
Restore, and ResetPersisted) have additional Sentry reporting as
these are the most common errors.

redoctober.go

@@ -9,6 +9,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -22,6 +23,7 @@ import (
 
 	"github.com/cloudflare/redoctober/config"
 	"github.com/cloudflare/redoctober/core"
+	"github.com/cloudflare/redoctober/report"
 	"github.com/coreos/go-systemd/activation"
 	"github.com/prometheus/client_golang/prometheus"
 )
@@ -67,20 +69,29 @@ func processRequest(requestType string, w http.ResponseWriter, r *http.Request)
 	header.Set("Content-Type", "application/json")
 	header.Set("Strict-Transport-Security", "max-age=86400; includeSubDomains; preload")
 
+	tags := map[string]string{
+		"request-type": requestType,
+		"request-from": r.RemoteAddr,
+	}
 	fn, ok := functions[requestType]
 	if !ok {
+		err := errors.New("redoctober: unknown request for " + requestType)
+		report.Check(err, tags)
 		http.Error(w, "Unknown request", http.StatusInternalServerError)
 		return
 	}
 
 	body, err := ioutil.ReadAll(r.Body)
 	if err != nil {
+		report.Check(err, tags)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
 	resp, err := fn(body)
 	if err != nil {
+		// The function should also report errors in more detail.
+		report.Check(err, tags)
 		log.Printf("http.main failed: %s: %s", requestType, err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
@@ -188,9 +199,13 @@ type indexHandler struct {
 
 func (this *indexHandler) handle(w http.ResponseWriter, r *http.Request) {
 	var body io.ReadSeeker
+	var tags = map[string]string{}
+
 	if this.staticPath != "" {
+		tags["static-path"] = this.staticPath
 		f, err := os.Open(this.staticPath)
 		if err != nil {
+			report.Check(err, tags)
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			return
 		}
@@ -219,7 +234,9 @@ func initPrometheus() {
 
 	log.Printf("metrics.init start: addr=%s", srv.Addr)
 	go func() {
-		log.Fatal(srv.ListenAndServe())
+		err := srv.ListenAndServe()
+		report.Check(err, nil)
+		log.Fatal(err.Error())
 	}()
 }
 
@@ -304,6 +321,8 @@ func main() {
 		cfg = cli
 	}
 
+	report.Init(cfg)
+
 	if vaultPath == "" || !cfg.Valid() {
 		if !cfg.Valid() {
 			fmt.Fprintf(os.Stderr, "Invalid config.\n")
@@ -314,6 +333,7 @@ func main() {
 	}
 
 	if err := core.Init(vaultPath, cfg); err != nil {
+		report.Check(err, nil)
 		log.Fatal(err)
 	}
 
@@ -323,9 +343,14 @@ func main() {
 	s, l, err := NewServer(cfg.UI.Static, cfg.Server.Addr, cfg.Server.CAPath,
 		cpaths, kpaths, cfg.Server.Systemd)
 	if err != nil {
+		report.Check(err, nil)
 		log.Fatalf("Error starting redoctober server: %s\n", err)
 	}
 
 	log.Printf("http.serve start: addr=%s", cfg.Server.Addr)
-	log.Fatal(s.Serve(l))
+	report.Recover(func() {
+		err := s.Serve(l)
+		report.Check(err, nil)
+		log.Fatal(err.Error())
+	})
 }