Improved implementation of custom HTML template

This implementation watches for changes to the template via inotify
instead of checking for every request. This also removes some URL
parsing logic duplication because the original mechanism can be
reused. Also, asset is gzipped for faster delivery.

Deprecate custom css because this makes it redundant.

UserManual.md

@@ -616,12 +616,6 @@ DESCRIPTION=Anything here will appear on the job page in the frontend <em>unesca
 
 Change `LAMINAR_TITLE` in `/etc/laminar.conf` to your preferred page title. Laminar must be restarted for this change to take effect.
 
-## Custom stylesheet
-
-If it exists, the file `/var/lib/laminar/custom/style.css` will be served by laminar and may be used to change the appearance of Laminar's WebUI.
-
-This directory is also a good place to add any extra assets needed for this customization, but note that in this case you will need to serve this directory directly from your [HTTP reverse proxy](#Service-configuration) (highly recommended).
-
 ## Custom HTML template
 
 If it exists, the file `/var/lib/laminar/custom/index.html` will be served by laminar instead of the default markup that is bundled into the Laminar binary. This file can be used to change any aspect of Laminar's WebUI, including adding custom menu links, stylesheets, or anything else. Any additional assets that are needed will need to be served directly from your [HTTP reverse proxy](#Service-configuration) (highly recommended).

src/http.cpp

@@ -211,16 +211,14 @@ kj::Promise<void> Http::request(kj::HttpMethod method, kj::StringPtr url, const
                 return writeEvents(p,s);
             }).attach(kj::mv(stream)).attach(kj::mv(peer));
         }
-    }
-    if(url.startsWith("/archive/")) {
+    } else if(url.startsWith("/archive/")) {
         KJ_IF_MAYBE(file, laminar.getArtefact(url.slice(strlen("/archive/")))) {
             auto array = (*file)->mmap(0, (*file)->stat().size);
             responseHeaders.add("Content-Transfer-Encoding", "binary");
             auto stream = response.send(200, "OK", responseHeaders, array.size());
             return stream->write(array.begin(), array.size()).attach(kj::mv(array)).attach(kj::mv(file)).attach(kj::mv(stream));
         }
-    }
-    if(parseLogEndpoint(url, name, num)) {
+    } else if(parseLogEndpoint(url, name, num)) {
         auto lw = kj::heap<WithSetRef<LogWatcher>>(logWatchers);
         lw->job = name;
         lw->run = num;
@@ -238,33 +236,19 @@ kj::Promise<void> Http::request(kj::HttpMethod method, kj::StringPtr url, const
                 return writeLogChunk(c, s);
             }).attach(kj::mv(output)).attach(kj::mv(stream)).attach(kj::mv(lw));
         }
-    }
-    if(url == "/custom/style.css") {
+    } else if(url == "/custom/style.css") {
         responseHeaders.set(kj::HttpHeaderId::CONTENT_TYPE, "text/css; charset=utf-8");
         responseHeaders.add("Content-Transfer-Encoding", "binary");
         std::string css = laminar.getCustomCss();
         auto stream = response.send(200, "OK", responseHeaders, css.size());
         return stream->write(css.data(), css.size()).attach(kj::mv(css)).attach(kj::mv(stream));
-    }
-    // If there is custom html defined, serve it. Otherwise, the default html
-    // will be served by the next block.
-    if(url == "/" || url == "/index.html" || url.startsWith("/jobs")) {
-        responseHeaders.set(kj::HttpHeaderId::CONTENT_TYPE, "text/html; charset=utf-8");
-        responseHeaders.add("Content-Transfer-Encoding", "binary");
-        std::string html = laminar.getCustomIndexHtml();
-        if (!html.empty()) {
-            auto stream = response.send(200, "OK", responseHeaders, html.size());
-            return stream->write(html.data(), html.size()).attach(kj::mv(html)).attach(kj::mv(stream));
-        }
-    }
-    if(resources->handleRequest(url.cStr(), &start, &end, &content_type)) {
+    } else if(resources->handleRequest(url.cStr(), &start, &end, &content_type)) {
         responseHeaders.set(kj::HttpHeaderId::CONTENT_TYPE, content_type);
         responseHeaders.add("Content-Encoding", "gzip");
         responseHeaders.add("Content-Transfer-Encoding", "binary");
         auto stream = response.send(200, "OK", responseHeaders, end-start);
         return stream->write(start, end-start).attach(kj::mv(stream));
-    }
-    if(url.startsWith("/badge/") && url.endsWith(".svg") && laminar.handleBadgeRequest(std::string(url.begin()+7, url.size()-11), badge)) {
+    } else if(url.startsWith("/badge/") && url.endsWith(".svg") && laminar.handleBadgeRequest(std::string(url.begin()+7, url.size()-11), badge)) {
         responseHeaders.set(kj::HttpHeaderId::CONTENT_TYPE, "image/svg+xml");
         responseHeaders.add("Cache-Control", "no-cache");
         auto stream = response.send(200, "OK", responseHeaders, badge.size());
@@ -313,3 +297,8 @@ void Http::notifyLog(std::string job, uint run, std::string log_chunk, bool eot)
         }
     }
 }
+
+void Http::setHtmlTemplate(std::string tmpl)
+{
+    resources->setHtmlTemplate(tmpl);
+}

src/http.h

@@ -43,6 +43,9 @@ public:
     void notifyEvent(const char* data, std::string job = nullptr);
     void notifyLog(std::string job, uint run, std::string log_chunk, bool eot);
 
+    // Allows supplying a custom HTML template. Pass an empty string to use the default.
+    void setHtmlTemplate(std::string tmpl = std::string());
+
 private:
     virtual kj::Promise<void> request(kj::HttpMethod method, kj::StringPtr url, const kj::HttpHeaders& headers,
                                       kj::AsyncInputStream& requestBody, Response& response) override;

src/laminar.cpp

@@ -113,6 +113,12 @@ Laminar::Laminar(Server &server, Settings settings) :
       .addPath((homePath/"cfg"/"jobs").toString(true).cStr())
       .addPath((homePath/"cfg").toString(true).cStr()); // for groups.conf
 
+    loadCustomizations();
+    srv.watchPaths([this]{
+        LLOG(INFO, "Reloading customizations");
+        loadCustomizations();
+    }).addPath((homePath/"custom").toString(true).cStr());
+
     srv.listenRpc(*rpc, settings.bind_rpc);
     srv.listenHttp(*http, settings.bind_http);
 
@@ -121,6 +127,14 @@ Laminar::Laminar(Server &server, Settings settings) :
     loadConfiguration();
 }
 
+void Laminar::loadCustomizations() {
+    KJ_IF_MAYBE(templ, fsHome->tryOpenFile(kj::Path{"custom","index.html"})) {
+        http->setHtmlTemplate((*templ)->readAllText().cStr());
+    } else {
+        http->setHtmlTemplate();
+    }
+}
+
 uint Laminar::latestRun(std::string job) {
     auto it = activeJobs.byJobName().equal_range(job);
     if(it.first == it.second) {
@@ -789,18 +803,16 @@ R"x(
     return true;
 }
 
+// TODO: deprecate
 std::string Laminar::getCustomCss() {
     KJ_IF_MAYBE(cssFile, fsHome->tryOpenFile(kj::Path{"custom","style.css"})) {
+        static bool warningShown = false;
+        if(!warningShown) {
+            LLOG(WARNING, "Custom CSS has been deprecated and will be removed from a future release. Use a custom HTML template instead.");
+            warningShown = true;
+        }
         return (*cssFile)->readAllText().cStr();
     } else {
         return std::string();
     }
 }
-
-std::string Laminar::getCustomIndexHtml() {
-    KJ_IF_MAYBE(htmlFile, fsHome->tryOpenFile(kj::Path{"custom","index.html"})) {
-        return (*htmlFile)->readAllText().cStr();
-    } else {
-        return std::string();
-    }
-}

src/laminar.h

@@ -95,10 +95,6 @@ public:
     // which handles this url.
     std::string getCustomCss();
 
-    // Fetches the content of $LAMINAR_HOME/custom/index.html or an empty
-    // string. This is used for custom template overrides.
-    std::string getCustomIndexHtml();
-
     // Aborts a single job
     bool abort(std::string job, uint buildNum);
 
@@ -107,6 +103,7 @@ public:
 
 private:
     bool loadConfiguration();
+    void loadCustomizations();
     void assignNewJobs();
     bool tryStartRun(std::shared_ptr<Run> run, int queueIndex);
     void handleRunFinished(Run*);

src/resources.cpp

@@ -37,7 +37,6 @@
 
 Resources::Resources()
 {
-    INIT_RESOURCE("/", index_html, CONTENT_TYPE_HTML);
     INIT_RESOURCE("/favicon.ico", favicon_ico, CONTENT_TYPE_ICO);
     INIT_RESOURCE("/favicon-152.png", favicon_152_png, CONTENT_TYPE_PNG);
     INIT_RESOURCE("/icon.png", icon_png, CONTENT_TYPE_PNG);
@@ -48,14 +47,36 @@ Resources::Resources()
     INIT_RESOURCE("/js/ansi_up.js", js_ansi_up_js, CONTENT_TYPE_JS);
     INIT_RESOURCE("/js/Chart.min.js", js_Chart_min_js, CONTENT_TYPE_JS);
     INIT_RESOURCE("/css/bootstrap.min.css", css_bootstrap_min_css, CONTENT_TYPE_CSS);
+    // Configure the default template
+    setHtmlTemplate(std::string());
+}
 
+void Resources::setHtmlTemplate(std::string tmpl) {
+    extern const char _binary_index_html_z_start[];
+    extern const char _binary_index_html_z_end[];
+
+    z_stream strm;
+    memset(&strm, 0, sizeof(z_stream));
+
+    if(!tmpl.empty()) {
+        // deflate
+        index_html.resize(tmpl.size());
+        deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, MAX_WBITS|GZIP_FORMAT, 8, Z_DEFAULT_STRATEGY);
+        strm.next_in = (unsigned char*) tmpl.data();
+        strm.avail_in = tmpl.size();
+        strm.next_out = (unsigned char*) index_html.data();
+        strm.avail_out = tmpl.size();
+        if(deflate(&strm, Z_FINISH) != Z_STREAM_END) {
+            LLOG(FATAL, "Failed to compress index.html");
+        }
+        index_html.resize(strm.total_out);
+    } else {
+        // use the default template from compile-time asset
         if(const char* baseUrl = getenv("LAMINAR_BASE_URL")) {
             // The administrator needs to customize the <base href>. Unfortunately this seems
             // to be the only thing that needs to be customizable but cannot be done via dynamic
             // DOM manipulation without heavy compromises. So replace the static char array with
             // a modified buffer accordingly.
-        z_stream strm;
-        memset(&strm, 0, sizeof(z_stream));
             std::string tmp;
             tmp.resize(INDEX_HTML_UNCOMPRESSED_SIZE);
             // inflate
@@ -84,10 +105,12 @@ Resources::Resources()
                 LLOG(FATAL, "Failed to compress index.html");
             }
             index_html.resize(strm.total_out);
-        // update resource map
-        resources["/"].start = index_html.data();
-        resources["/"].end = index_html.data() + index_html.size();
+        } else {
+            index_html = std::string(_binary_index_html_z_start, _binary_index_html_z_end);
         }
+    }
+    // update resource map
+    resources["/"] = Resource{index_html.data(), index_html.data() + index_html.size(), CONTENT_TYPE_HTML};
 }
 
 inline bool beginsWith(std::string haystack, const char* needle) {

src/resources.h

@@ -34,6 +34,9 @@ public:
     // type. Function returns false if no resource for the given path exists
     bool handleRequest(std::string path, const char** start, const char** end, const char** content_type);
 
+    // Allows providing a custom HTML template. Pass an empty string to use the default.
+    void setHtmlTemplate(std::string templ = std::string());
+
 private:
     struct Resource {
         const char* start;