|
| 1 | +package handler |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "context" |
| 6 | + "fmt" |
| 7 | + "html/template" |
| 8 | + "net/http" |
| 9 | + "time" |
| 10 | + |
| 11 | + "github.com/kedacore/http-add-on/operator/apis/http/v1alpha1" |
| 12 | + "github.com/kedacore/http-add-on/pkg/routing" |
| 13 | + metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" |
| 14 | + "k8s.io/client-go/kubernetes" |
| 15 | +) |
| 16 | + |
| 17 | +const defaultPlaceholderTemplate = `<!DOCTYPE html> |
| 18 | +<html> |
| 19 | +<head> |
| 20 | + <title>Service Starting</title> |
| 21 | + <meta http-equiv="refresh" content="{{.RefreshInterval}}"> |
| 22 | + <meta charset="utf-8"> |
| 23 | + <style> |
| 24 | + body { |
| 25 | + font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; |
| 26 | + display: flex; |
| 27 | + align-items: center; |
| 28 | + justify-content: center; |
| 29 | + min-height: 100vh; |
| 30 | + margin: 0; |
| 31 | + background: #f5f5f5; |
| 32 | + } |
| 33 | + .container { |
| 34 | + text-align: center; |
| 35 | + padding: 2rem; |
| 36 | + background: white; |
| 37 | + border-radius: 8px; |
| 38 | + box-shadow: 0 2px 10px rgba(0,0,0,0.1); |
| 39 | + max-width: 400px; |
| 40 | + } |
| 41 | + h1 { |
| 42 | + color: #333; |
| 43 | + margin-bottom: 1rem; |
| 44 | + font-size: 1.5rem; |
| 45 | + } |
| 46 | + .spinner { |
| 47 | + width: 40px; |
| 48 | + height: 40px; |
| 49 | + margin: 1.5rem auto; |
| 50 | + border: 4px solid #f3f3f3; |
| 51 | + border-top: 4px solid #3498db; |
| 52 | + border-radius: 50%; |
| 53 | + animation: spin 1s linear infinite; |
| 54 | + } |
| 55 | + @keyframes spin { |
| 56 | + 0% { transform: rotate(0deg); } |
| 57 | + 100% { transform: rotate(360deg); } |
| 58 | + } |
| 59 | + p { |
| 60 | + color: #666; |
| 61 | + margin: 0.5rem 0; |
| 62 | + } |
| 63 | + .small { |
| 64 | + font-size: 0.875rem; |
| 65 | + color: #999; |
| 66 | + } |
| 67 | + </style> |
| 68 | +</head> |
| 69 | +<body> |
| 70 | + <div class="container"> |
| 71 | + <h1>{{.ServiceName}} is starting up...</h1> |
| 72 | + <div class="spinner"></div> |
| 73 | + <p>Please wait while we prepare your service.</p> |
| 74 | + <p class="small">This page will refresh automatically every {{.RefreshInterval}} seconds.</p> |
| 75 | + </div> |
| 76 | +</body> |
| 77 | +</html>` |
| 78 | + |
| 79 | +// PlaceholderHandler handles serving placeholder pages during scale-from-zero |
| 80 | +type PlaceholderHandler struct { |
| 81 | + k8sClient kubernetes.Interface |
| 82 | + routingTable routing.Table |
| 83 | + templateCache map[string]*template.Template |
| 84 | + defaultTmpl *template.Template |
| 85 | +} |
| 86 | + |
| 87 | +// PlaceholderData contains data for rendering placeholder templates |
| 88 | +type PlaceholderData struct { |
| 89 | + ServiceName string |
| 90 | + Namespace string |
| 91 | + RefreshInterval int32 |
| 92 | + RequestID string |
| 93 | + Timestamp string |
| 94 | +} |
| 95 | + |
| 96 | +// NewPlaceholderHandler creates a new placeholder handler |
| 97 | +func NewPlaceholderHandler(k8sClient kubernetes.Interface, routingTable routing.Table) (*PlaceholderHandler, error) { |
| 98 | + defaultTmpl, err := template.New("default").Parse(defaultPlaceholderTemplate) |
| 99 | + if err != nil { |
| 100 | + return nil, fmt.Errorf("failed to parse default template: %w", err) |
| 101 | + } |
| 102 | + |
| 103 | + return &PlaceholderHandler{ |
| 104 | + k8sClient: k8sClient, |
| 105 | + routingTable: routingTable, |
| 106 | + templateCache: make(map[string]*template.Template), |
| 107 | + defaultTmpl: defaultTmpl, |
| 108 | + }, nil |
| 109 | +} |
| 110 | + |
| 111 | +// ServePlaceholder serves a placeholder page based on the HTTPScaledObject configuration |
| 112 | +func (h *PlaceholderHandler) ServePlaceholder(w http.ResponseWriter, r *http.Request, hso *v1alpha1.HTTPScaledObject) error { |
| 113 | + if hso.Spec.PlaceholderConfig == nil || !hso.Spec.PlaceholderConfig.Enabled { |
| 114 | + http.Error(w, "Service temporarily unavailable", http.StatusServiceUnavailable) |
| 115 | + return nil |
| 116 | + } |
| 117 | + |
| 118 | + config := hso.Spec.PlaceholderConfig |
| 119 | + |
| 120 | + statusCode := int(config.StatusCode) |
| 121 | + if statusCode == 0 { |
| 122 | + statusCode = http.StatusServiceUnavailable |
| 123 | + } |
| 124 | + |
| 125 | + for k, v := range config.Headers { |
| 126 | + w.Header().Set(k, v) |
| 127 | + } |
| 128 | + |
| 129 | + w.Header().Set("Content-Type", "text/html; charset=utf-8") |
| 130 | + w.Header().Set("X-KEDA-HTTP-Placeholder-Served", "true") |
| 131 | + w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate") |
| 132 | + |
| 133 | + tmpl, err := h.getTemplate(r.Context(), hso) |
| 134 | + if err != nil { |
| 135 | + w.WriteHeader(statusCode) |
| 136 | + fmt.Fprintf(w, "<h1>%s is starting up...</h1><meta http-equiv='refresh' content='%d'>", |
| 137 | + hso.Spec.ScaleTargetRef.Service, config.RefreshInterval) |
| 138 | + return nil |
| 139 | + } |
| 140 | + |
| 141 | + data := PlaceholderData{ |
| 142 | + ServiceName: hso.Spec.ScaleTargetRef.Service, |
| 143 | + Namespace: hso.Namespace, |
| 144 | + RefreshInterval: config.RefreshInterval, |
| 145 | + RequestID: r.Header.Get("X-Request-ID"), |
| 146 | + Timestamp: time.Now().Format(time.RFC3339), |
| 147 | + } |
| 148 | + |
| 149 | + var buf bytes.Buffer |
| 150 | + if err := tmpl.Execute(&buf, data); err != nil { |
| 151 | + w.WriteHeader(statusCode) |
| 152 | + fmt.Fprintf(w, "<h1>%s is starting up...</h1><meta http-equiv='refresh' content='%d'>", |
| 153 | + hso.Spec.ScaleTargetRef.Service, config.RefreshInterval) |
| 154 | + return nil |
| 155 | + } |
| 156 | + |
| 157 | + w.WriteHeader(statusCode) |
| 158 | + _, err = w.Write(buf.Bytes()) |
| 159 | + return err |
| 160 | +} |
| 161 | + |
| 162 | +// getTemplate retrieves the template for the given HTTPScaledObject |
| 163 | +func (h *PlaceholderHandler) getTemplate(ctx context.Context, hso *v1alpha1.HTTPScaledObject) (*template.Template, error) { |
| 164 | + config := hso.Spec.PlaceholderConfig |
| 165 | + |
| 166 | + if config.Content != "" { |
| 167 | + cacheKey := fmt.Sprintf("%s/%s/inline", hso.Namespace, hso.Name) |
| 168 | + if tmpl, ok := h.templateCache[cacheKey]; ok { |
| 169 | + return tmpl, nil |
| 170 | + } |
| 171 | + |
| 172 | + tmpl, err := template.New("inline").Parse(config.Content) |
| 173 | + if err != nil { |
| 174 | + return nil, err |
| 175 | + } |
| 176 | + h.templateCache[cacheKey] = tmpl |
| 177 | + return tmpl, nil |
| 178 | + } |
| 179 | + |
| 180 | + if config.ContentConfigMap != "" { |
| 181 | + cacheKey := fmt.Sprintf("%s/%s/cm/%s", hso.Namespace, hso.Name, config.ContentConfigMap) |
| 182 | + if tmpl, ok := h.templateCache[cacheKey]; ok { |
| 183 | + return tmpl, nil |
| 184 | + } |
| 185 | + |
| 186 | + cm, err := h.k8sClient.CoreV1().ConfigMaps(hso.Namespace).Get(ctx, config.ContentConfigMap, metav1.GetOptions{}) |
| 187 | + if err != nil { |
| 188 | + return nil, fmt.Errorf("failed to get ConfigMap %s: %w", config.ContentConfigMap, err) |
| 189 | + } |
| 190 | + |
| 191 | + key := config.ContentConfigMapKey |
| 192 | + if key == "" { |
| 193 | + key = "template.html" |
| 194 | + } |
| 195 | + |
| 196 | + content, ok := cm.Data[key] |
| 197 | + if !ok { |
| 198 | + return nil, fmt.Errorf("key %s not found in ConfigMap %s", key, config.ContentConfigMap) |
| 199 | + } |
| 200 | + |
| 201 | + tmpl, err := template.New("configmap").Parse(content) |
| 202 | + if err != nil { |
| 203 | + return nil, err |
| 204 | + } |
| 205 | + h.templateCache[cacheKey] = tmpl |
| 206 | + return tmpl, nil |
| 207 | + } |
| 208 | + |
| 209 | + return h.defaultTmpl, nil |
| 210 | +} |
| 211 | + |
| 212 | +// ClearCache clears the template cache |
| 213 | +func (h *PlaceholderHandler) ClearCache() { |
| 214 | + h.templateCache = make(map[string]*template.Template) |
| 215 | +} |
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