Add database stats

api/openapi.yml

@@ -15,7 +15,7 @@ tags:
   - name: Admin
     description: Manage PURLs
   - name: System
-    description: Endpoints for interacting / managing the overal system
+    description: Endpoints for interacting / managing the overall system
 
 security: []
 
@@ -31,6 +31,24 @@ paths:
         500:
           description: Service is not healthy
 
+  /s/stats/public:
+    get:
+      operationId: getPublicStats
+      summary: Get public stats about this system
+      tags: [System]
+      responses:
+        200:
+          description: Returns stats
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  domains_total:
+                    type: integer
+                  purls_total:
+                    type: integer
+
   /r/{domain}/{name}:
     get:
       operationId: resolvePURL

api/server.go

@@ -2,10 +2,8 @@ package api
 
 import (
 	"errors"
-	"fmt"
 	"net/http"
 
-	"github.com/fabiante/persurl/api/res"
 	"github.com/fabiante/persurl/app"
 	"github.com/gin-gonic/gin"
 )
@@ -34,40 +32,3 @@ func (s *Server) Resolve(ctx *gin.Context) {
 		respondWithError(ctx, http.StatusInternalServerError, err)
 	}
 }
-
-func (s *Server) SavePURL(ctx *gin.Context) {
-	domain := ctx.Param("domain")
-	name := ctx.Param("name")
-
-	var req res.SavePURL
-	if err := ctx.BindJSON(&req); err != nil {
-		ctx.Abort()
-		return
-	}
-
-	err := s.service.SavePURL(domain, name, req.Target)
-	switch true {
-	case err == nil:
-		break
-	case errors.Is(err, app.ErrBadRequest):
-		respondWithError(ctx, http.StatusBadRequest, err)
-	default:
-		respondWithError(ctx, http.StatusInternalServerError, err)
-	}
-
-	ctx.JSON(http.StatusOK, res.NewSavePURLResponse(fmt.Sprintf("/r/%s/%s", domain, name)))
-}
-
-func (s *Server) CreateDomain(ctx *gin.Context) {
-	domain := ctx.Param("domain")
-
-	err := s.service.CreateDomain(domain)
-	switch true {
-	case err == nil:
-		ctx.Status(http.StatusNoContent)
-	case errors.Is(err, app.ErrBadRequest):
-		respondWithError(ctx, http.StatusBadRequest, err)
-	default:
-		respondWithError(ctx, http.StatusInternalServerError, err)
-	}
-}

api/server_admin.go

@@ -0,0 +1,48 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/fabiante/persurl/api/res"
+	"github.com/fabiante/persurl/app"
+	"github.com/gin-gonic/gin"
+)
+
+func (s *Server) SavePURL(ctx *gin.Context) {
+	domain := ctx.Param("domain")
+	name := ctx.Param("name")
+
+	var req res.SavePURL
+	if err := ctx.BindJSON(&req); err != nil {
+		ctx.Abort()
+		return
+	}
+
+	err := s.service.SavePURL(domain, name, req.Target)
+	switch true {
+	case err == nil:
+		break
+	case errors.Is(err, app.ErrBadRequest):
+		respondWithError(ctx, http.StatusBadRequest, err)
+	default:
+		respondWithError(ctx, http.StatusInternalServerError, err)
+	}
+
+	ctx.JSON(http.StatusOK, res.NewSavePURLResponse(fmt.Sprintf("/r/%s/%s", domain, name)))
+}
+
+func (s *Server) CreateDomain(ctx *gin.Context) {
+	domain := ctx.Param("domain")
+
+	err := s.service.CreateDomain(domain)
+	switch true {
+	case err == nil:
+		ctx.Status(http.StatusNoContent)
+	case errors.Is(err, app.ErrBadRequest):
+		respondWithError(ctx, http.StatusBadRequest, err)
+	default:
+		respondWithError(ctx, http.StatusInternalServerError, err)
+	}
+}

api/server_routes.go

@@ -57,5 +57,7 @@ func SetupRouting(r gin.IRouter, s *Server) {
 
 			ctx.JSON(http.StatusOK, "service is ready to receive requests")
 		})
+
+		sys.GET("/stats/public", s.GetPublicStats)
 	}
 }

api/server_stats.go

@@ -0,0 +1,18 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func (s *Server) GetPublicStats(ctx *gin.Context) {
+	stats, err := s.service.DetermineServiceStats()
+
+	switch true {
+	case err == nil:
+		ctx.JSON(http.StatusOK, stats)
+	default:
+		respondWithError(ctx, http.StatusInternalServerError, err)
+	}
+}

app/service.go

@@ -16,4 +16,15 @@ type ServiceInterface interface {
 	//
 	// ErrBadRequest is returned if the domain already exists.
 	CreateDomain(domain string) error
+
+	// DetermineServiceStats calculates statistics about the service.
+	//
+	// This is potentially an expensive operation and should not be called
+	// frequently.
+	DetermineServiceStats() (*Stats, error)
+}
+
+type Stats struct {
+	DomainsTotal int `json:"domains_total"`
+	PurlsTotal   int `json:"purls_total"`
 }

db/database.go

@@ -101,6 +101,34 @@ func (db *Database) CreateDomain(domain string) error {
 	}
 }
 
+func (db *Database) DetermineServiceStats() (*app.Stats, error) {
+	stat := &app.Stats{}
+	var errs []error
+	var err error
+
+	stat.DomainsTotal, err = db.countRows("domains", "id")
+	errs = append(errs, err)
+
+	stat.PurlsTotal, err = db.countRows("purls", "id")
+	errs = append(errs, err)
+
+	return stat, errors.Join(errs...)
+}
+
+func (db *Database) countRows(table string, column string) (int, error) {
+	var count int
+
+	found, err := db.db.From("domains").Select(goqu.COUNT(goqu.C("id"))).ScanVal(&count)
+	switch {
+	case err != nil:
+		return 0, fmt.Errorf("failed to count rows of table %s: %w", table, err)
+	case !found:
+		return 0, fmt.Errorf("failed to count rows of table %s, no rows found: %w", table, err)
+	}
+
+	return count, nil
+}
+
 const (
 	pgErrUniqueKeyViolation = "23505"
 )