threatfeed: Pre-parse and cache html templates

This change pre-parses all html templates from the `templates` directory and stores the results globally. With this change, http handlers no longer need to re-parse templates on every request.

internal/threatfeed/handler-logs.go

@@ -3,7 +3,6 @@ package threatfeed
 import (
 	"cmp"
 	"encoding/json"
-	"html/template"
 	"io"
 	"net/http"
 	"os"
@@ -14,8 +13,7 @@ import (
 // handleLogsMain serves a static page listing honeypot logs available for
 // viewing.
 func handleLogsMain(w http.ResponseWriter, r *http.Request) {
-	tmpl := template.Must(template.ParseFS(templates, "templates/logs.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "logs.html", "logs")
+	_ = parsedTemplates.ExecuteTemplate(w, "logs.html", "logs")
 }
 
 // handleLogs directs the request to the appropriate log parser based on the
@@ -65,8 +63,7 @@ func handleLogs(w http.ResponseWriter, r *http.Request) {
 // log files.
 func displayLogErrorPage(w http.ResponseWriter, err error) {
 	w.WriteHeader(http.StatusInternalServerError)
-	tmpl := template.Must(template.ParseFS(templates, "templates/logs-error.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "logs-error.html", map[string]any{"Error": err, "NavData": "logs"})
+	_ = parsedTemplates.ExecuteTemplate(w, "logs-error.html", map[string]any{"Error": err, "NavData": "logs"})
 }
 
 // handleLogSSH serves the SSH honeypot logs as a web page. It opens the
@@ -107,8 +104,7 @@ func handleLogSSH(w http.ResponseWriter) {
 	}
 	slices.Reverse(data)
 
-	tmpl := template.Must(template.ParseFS(templates, "templates/logs-ssh.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "logs-ssh.html", map[string]any{"Data": data, "NavData": "logs"})
+	_ = parsedTemplates.ExecuteTemplate(w, "logs-ssh.html", map[string]any{"Data": data, "NavData": "logs"})
 }
 
 // handleLogHTTP serves the HTTP honeypot logs as a web page. It opens the
@@ -149,8 +145,7 @@ func handleLogHTTP(w http.ResponseWriter) {
 	}
 	slices.Reverse(data)
 
-	tmpl := template.Must(template.ParseFS(templates, "templates/logs-http.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "logs-http.html", map[string]any{"Data": data, "NavData": "logs"})
+	_ = parsedTemplates.ExecuteTemplate(w, "logs-http.html", map[string]any{"Data": data, "NavData": "logs"})
 }
 
 // displayStats handles the processing and rendering of statistics for a given
@@ -178,8 +173,7 @@ func displayStats(w http.ResponseWriter, field fieldCounter) {
 		)
 	})
 
-	tmpl := template.Must(template.ParseFS(templates, "templates/logs-stats.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(
+	_ = parsedTemplates.ExecuteTemplate(
 		w,
 		"logs-stats.html",
 		map[string]any{

internal/threatfeed/handler-websocket.go

@@ -2,7 +2,6 @@ package threatfeed
 
 import (
 	"fmt"
-	"html/template"
 	"net"
 	"net/http"
 	"sync"
@@ -29,8 +28,7 @@ var (
 // handleLiveIndex serves a web page that displays honeypot log data in
 // real-time through a WebSocket connection.
 func handleLiveIndex(w http.ResponseWriter, r *http.Request) {
-	tmpl := template.Must(template.ParseFS(templates, "templates/live.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "live.html", "live")
+	_ = parsedTemplates.ExecuteTemplate(w, "live.html", "live")
 }
 
 // broadcastLogsToClients receives honeypot log data through a byte channel

internal/threatfeed/handler.go

@@ -22,6 +22,11 @@ import (
 //go:embed templates
 var templates embed.FS
 
+// parsedTemplates pre-parses and caches all HTML templates when the threat
+// feed server starts. This eliminates the need for HTTP handlers to re-parse
+// templates on each request.
+var parsedTemplates = template.Must(template.ParseFS(templates, "templates/*.html"))
+
 // handlePlain handles HTTP requests to serve the threat feed in plain text. It
 // returns a list of IP addresses that interacted with the honeypot servers.
 func handlePlain(w http.ResponseWriter, r *http.Request) {
@@ -281,15 +286,13 @@ func handleTAXIIObjects(w http.ResponseWriter, r *http.Request) {
 // delivers a static HTML document with information on accessing the threat
 // feed.
 func handleHome(w http.ResponseWriter, r *http.Request) {
-	tmpl := template.Must(template.ParseFS(templates, "templates/home.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "home.html", "home")
+	_ = parsedTemplates.ExecuteTemplate(w, "home.html", "home")
 }
 
 // handleDocs serves a static page with documentation for accessing the threat
 // feed.
 func handleDocs(w http.ResponseWriter, r *http.Request) {
-	tmpl := template.Must(template.ParseFS(templates, "templates/docs.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "docs.html", "docs")
+	_ = parsedTemplates.ExecuteTemplate(w, "docs.html", "docs")
 }
 
 // handleCSS serves a CSS stylesheet for styling HTML templates.
@@ -311,8 +314,7 @@ func handleConfig(w http.ResponseWriter, r *http.Request) {
 		NavData string
 	}
 	d := templateData{C: cfg, Version: config.Version, NavData: "config"}
-	tmpl := template.Must(template.ParseFS(templates, "templates/config.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(w, "config.html", d)
+	_ = parsedTemplates.ExecuteTemplate(w, "config.html", d)
 }
 
 // handleHTML returns the threat feed as a web page for viewing in a browser.
@@ -347,8 +349,7 @@ func handleHTML(w http.ResponseWriter, r *http.Request) {
 		m = "observations"
 	}
 
-	tmpl := template.Must(template.ParseFS(templates, "templates/webfeed.html", "templates/nav.html"))
-	_ = tmpl.ExecuteTemplate(
+	_ = parsedTemplates.ExecuteTemplate(
 		w,
 		"webfeed.html",
 		map[string]any{"Data": prepareFeed(opt), "SortDirection": d, "SortMethod": m, "NavData": "webfeed"},
@@ -459,6 +460,5 @@ func parseParams(r *http.Request) (feedOptions, error) {
 // response when a request is made to an undefined path.
 func handleNotFound(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNotFound)
-	tmpl := template.Must(template.ParseFS(templates, "templates/404.html"))
-	_ = tmpl.Execute(w, nil)
+	_ = parsedTemplates.ExecuteTemplate(w, "404.html", nil)
 }