Initial Commit

2023-10-02 12:50:34 +02:00
commit 3998f9e2c2
38 changed files with 3485 additions and 0 deletions
--- a/server/auth.go
+++ b/server/auth.go
@ -0,0 +1,17 @@
+package server
+
+import (
+	"net/http"
+
+	"git.cryptic.systems/volker.raschek/prometheus-fail2ban-exporter/auth"
+)
+
+func AuthMiddleware(handlerFunc http.HandlerFunc, authProvider auth.AuthProvider) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if authProvider.IsAllowed(r) {
+			handlerFunc.ServeHTTP(w, r)
+		} else {
+			w.WriteHeader(http.StatusUnauthorized)
+		}
+	}
+}
--- a/server/auth_test.go
+++ b/server/auth_test.go
@ -0,0 +1,46 @@
+package server
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+type testAuthProvider struct {
+	match bool
+}
+
+func (p testAuthProvider) IsAllowed(request *http.Request) bool {
+	return p.match
+}
+
+func newTestRequest() *http.Request {
+	return httptest.NewRequest(http.MethodGet, "http://example.com", nil)
+}
+
+func executeAuthMiddlewareTest(t *testing.T, authMatches bool, expectedCode int, expectedCallCount int) {
+	callCount := 0
+	testHandler := func(w http.ResponseWriter, r *http.Request) {
+		callCount++
+	}
+
+	handler := AuthMiddleware(testHandler, testAuthProvider{match: authMatches})
+	recorder := httptest.NewRecorder()
+	request := newTestRequest()
+	handler.ServeHTTP(recorder, request)
+
+	if recorder.Code != expectedCode {
+		t.Errorf("statusCode = %v, want %v", recorder.Code, expectedCode)
+	}
+	if callCount != expectedCallCount {
+		t.Errorf("callCount = %v, want %v", callCount, expectedCallCount)
+	}
+}
+
+func Test_GIVEN_MatchingBasicAuth_WHEN_MethodCalled_THEN_RequestProcessed(t *testing.T) {
+	executeAuthMiddlewareTest(t, true, http.StatusOK, 1)
+}
+
+func Test_GIVEN_NonMatchingBasicAuth_WHEN_MethodCalled_THEN_RequestRejected(t *testing.T) {
+	executeAuthMiddlewareTest(t, false, http.StatusUnauthorized, 0)
+}
--- a/server/handler.go
+++ b/server/handler.go
@ -0,0 +1,33 @@
+package server
+
+import (
+	"log"
+	"net/http"
+
+	"git.cryptic.systems/volker.raschek/prometheus-fail2ban-exporter/collector/textfile"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+const (
+	metricsPath = "/metrics"
+)
+
+func rootHtmlHandler(w http.ResponseWriter, r *http.Request) {
+	_, err := w.Write([]byte(
+		`<html>
+			<head><title>Fail2Ban Exporter</title></head>
+			<body>
+			<h1>Fail2Ban Exporter</h1>
+			<p><a href="` + metricsPath + `">Metrics</a></p>
+			</body>
+		</html>`))
+	if err != nil {
+		log.Printf("error handling root url: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+}
+
+func metricHandler(w http.ResponseWriter, r *http.Request, collector *textfile.Collector) {
+	promhttp.Handler().ServeHTTP(w, r)
+	collector.WriteTextFileMetrics(w, r)
+}
--- a/server/server.go
+++ b/server/server.go
@ -0,0 +1,41 @@
+package server
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"git.cryptic.systems/volker.raschek/prometheus-fail2ban-exporter/cfg"
+	"git.cryptic.systems/volker.raschek/prometheus-fail2ban-exporter/collector/textfile"
+)
+
+func StartServer(
+	appSettings *cfg.AppSettings,
+	textFileCollector *textfile.Collector,
+) chan error {
+	http.HandleFunc("/", AuthMiddleware(
+		rootHtmlHandler,
+		appSettings.AuthProvider,
+	))
+	http.HandleFunc(metricsPath, AuthMiddleware(
+		func(w http.ResponseWriter, r *http.Request) {
+			metricHandler(w, r, textFileCollector)
+		},
+		appSettings.AuthProvider,
+	))
+	log.Printf("metrics available at '%s'", metricsPath)
+
+	svrErr := make(chan error)
+	go func() {
+		httpServer := &http.Server{
+			Addr:              appSettings.MetricsAddress,
+			ReadHeaderTimeout: 10 * time.Second,
+			ReadTimeout:       10 * time.Second,
+			WriteTimeout:      10 * time.Second,
+			IdleTimeout:       30 * time.Second,
+		}
+		svrErr <- httpServer.ListenAndServe()
+	}()
+	log.Print("ready")
+	return svrErr
+}