feat: first

internal/health/health.go

@@ -0,0 +1,112 @@
+package health
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+)
+
+// Response represents a health check response
+type Response struct {
+	Status    string    `json:"status"`
+	Timestamp time.Time `json:"timestamp"`
+	Version   string    `json:"version,omitempty"`
+	Checks    []Check   `json:"checks,omitempty"`
+}
+
+// Check represents an individual health check
+type Check struct {
+	Name   string `json:"name"`
+	Status string `json:"status"`
+	Error  string `json:"error,omitempty"`
+}
+
+// Handler handles health check requests
+type Handler struct {
+	version string
+	checks  []HealthChecker
+}
+
+// HealthChecker interface for health checks
+type HealthChecker interface {
+	Name() string
+	Check() error
+}
+
+// NewHandler creates a new health check handler
+func NewHandler(version string) *Handler {
+	return &Handler{
+		version: version,
+		checks:  make([]HealthChecker, 0),
+	}
+}
+
+// AddCheck adds a health checker
+func (h *Handler) AddCheck(checker HealthChecker) {
+	h.checks = append(h.checks, checker)
+}
+
+// ServeHTTP implements http.Handler
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+
+	response := Response{
+		Status:    "ok",
+		Timestamp: time.Now().UTC(),
+		Version:   h.version,
+		Checks:    make([]Check, 0, len(h.checks)),
+	}
+
+	allHealthy := true
+	for _, checker := range h.checks {
+		check := Check{
+			Name:   checker.Name(),
+			Status: "ok",
+		}
+
+		if err := checker.Check(); err != nil {
+			check.Status = "error"
+			check.Error = err.Error()
+			allHealthy = false
+		}
+
+		response.Checks = append(response.Checks, check)
+	}
+
+	if !allHealthy {
+		response.Status = "error"
+		w.WriteHeader(http.StatusServiceUnavailable)
+	} else {
+		w.WriteHeader(http.StatusOK)
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(response)
+}
+
+// SimpleChecker is a basic health checker
+type SimpleChecker struct {
+	name string
+	fn   func() error
+}
+
+// NewSimpleChecker creates a new simple health checker
+func NewSimpleChecker(name string, fn func() error) *SimpleChecker {
+	return &SimpleChecker{
+		name: name,
+		fn:   fn,
+	}
+}
+
+// Name returns the checker name
+func (c *SimpleChecker) Name() string {
+	return c.name
+}
+
+// Check performs the health check
+func (c *SimpleChecker) Check() error {
+	return c.fn()
+}

internal/health/health_test.go

@@ -0,0 +1,115 @@
+package health
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestHealthHandler_ServeHTTP(t *testing.T) {
+	tests := []struct {
+		name           string
+		method         string
+		checkers       []HealthChecker
+		expectedStatus int
+		expectedHealth string
+	}{
+		{
+			name:           "GET request with no checkers",
+			method:         "GET",
+			checkers:       []HealthChecker{},
+			expectedStatus: http.StatusOK,
+			expectedHealth: "ok",
+		},
+		{
+			name:   "GET request with healthy checker",
+			method: "GET",
+			checkers: []HealthChecker{
+				NewSimpleChecker("test", func() error { return nil }),
+			},
+			expectedStatus: http.StatusOK,
+			expectedHealth: "ok",
+		},
+		{
+			name:   "GET request with unhealthy checker",
+			method: "GET",
+			checkers: []HealthChecker{
+				NewSimpleChecker("test", func() error { return errors.New("test error") }),
+			},
+			expectedStatus: http.StatusServiceUnavailable,
+			expectedHealth: "error",
+		},
+		{
+			name:           "POST request should return 405",
+			method:         "POST",
+			checkers:       []HealthChecker{},
+			expectedStatus: http.StatusMethodNotAllowed,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			handler := NewHandler("1.0.0")
+			for _, checker := range tt.checkers {
+				handler.AddCheck(checker)
+			}
+
+			req := httptest.NewRequest(tt.method, "/health", nil)
+			w := httptest.NewRecorder()
+
+			handler.ServeHTTP(w, req)
+
+			if w.Code != tt.expectedStatus {
+				t.Errorf("expected status %d, got %d", tt.expectedStatus, w.Code)
+			}
+
+			if tt.method == "GET" && tt.expectedStatus != http.StatusMethodNotAllowed {
+				var response Response
+				if err := json.NewDecoder(w.Body).Decode(&response); err != nil {
+					t.Fatalf("failed to decode response: %v", err)
+				}
+
+				if response.Status != tt.expectedHealth {
+					t.Errorf("expected status %s, got %s", tt.expectedHealth, response.Status)
+				}
+
+				if response.Version != "1.0.0" {
+					t.Errorf("expected version 1.0.0, got %s", response.Version)
+				}
+
+				if len(response.Checks) != len(tt.checkers) {
+					t.Errorf("expected %d checks, got %d", len(tt.checkers), len(response.Checks))
+				}
+			}
+		})
+	}
+}
+
+func TestSimpleChecker(t *testing.T) {
+	t.Run("healthy checker", func(t *testing.T) {
+		checker := NewSimpleChecker("test", func() error { return nil })
+		
+		if checker.Name() != "test" {
+			t.Errorf("expected name 'test', got %s", checker.Name())
+		}
+		
+		if err := checker.Check(); err != nil {
+			t.Errorf("expected no error, got %v", err)
+		}
+	})
+
+	t.Run("unhealthy checker", func(t *testing.T) {
+		testErr := errors.New("test error")
+		checker := NewSimpleChecker("test", func() error { return testErr })
+		
+		if checker.Name() != "test" {
+			t.Errorf("expected name 'test', got %s", checker.Name())
+		}
+		
+		if err := checker.Check(); err != testErr {
+			t.Errorf("expected error %v, got %v", testErr, err)
+		}
+	})
+}