feat: log article API failures to database

- Created api_logs table (username, article_name, status_code,
  response_time_ms, error, request_url)
- GetArticle logs failures (network errors and non-2xx responses)
  with timing, status code, and response body
- Successful requests are not logged

2 files changed, 50 insertions, 2 deletions

diff --git a/api/handlers.go b/api/handlers.go
index c9c3031..04fcc23 100644
--- a/api/handlers.go
+++ b/api/handlers.go
@@ -227,16 +227,30 @@ func (h *Handler) GetArticle(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	base := "https://api.enterprise.wikimedia.com/v2/structured-contents/" + url.QueryEscape(article)
-	req, err := http.NewRequestWithContext(ctx, "GET", base+"?limit=1&filters[project]=en.wikipedia.org", nil)
+	baseURL := "https://api.enterprise.wikimedia.com/v2/structured-contents/" + url.QueryEscape(article)
+	queryURL := baseURL + "?limit=1&filters[project]=en.wikipedia.org"
+
+	req, err := http.NewRequestWithContext(ctx, "GET", queryURL, nil)
 	if err != nil {
 		serverError(w, "could not build request")
 		return
 	}
 	req.Header.Set("Authorization", "Bearer "+acct.AccessToken)
 
+	start := time.Now()
 	resp, err := http.DefaultClient.Do(req)
+	elapsed := int(time.Since(start).Milliseconds())
+
 	if err != nil {
+		log.Printf("article request failed: user=%s article=%s error=%v (%dms)", username, article, err, elapsed)
+		h.db.LogApiCall(ctx, &db.ApiLogEntry{
+			Username:    username,
+			ArticleName: article,
+			StatusCode:  0,
+			ResponseMs:  elapsed,
+			Error:       err.Error(),
+			RequestURL:  queryURL,
+		})
 		serverError(w, "wikimedia api error")
 		return
 	}
@@ -244,6 +258,16 @@ func (h *Handler) GetArticle(w http.ResponseWriter, r *http.Request) {
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
 		b, _ := io.ReadAll(resp.Body)
+		log.Printf("article request failed: user=%s article=%s status=%d body=%s (%dms)",
+			username, article, resp.StatusCode, string(b), elapsed)
+		h.db.LogApiCall(ctx, &db.ApiLogEntry{
+			Username:    username,
+			ArticleName: article,
+			StatusCode:  resp.StatusCode,
+			ResponseMs:  elapsed,
+			Error:       string(b),
+			RequestURL:  queryURL,
+		})
 		http.Error(w, string(b), resp.StatusCode)
 		return
 	}
diff --git a/db/db.go b/db/db.go
index 228a655..7409047 100644
--- a/db/db.go
+++ b/db/db.go
@@ -325,3 +325,27 @@ func (d *DB) HealthCheck(ctx context.Context) error {
 	_, err := d.conn.ExecContext(ctx, "SELECT 1")
 	return err
 }
+
+// ApiLogEntry represents an API call log.
+type ApiLogEntry struct {
+	Username    string
+	ArticleName string
+	StatusCode  int
+	ResponseMs  int
+	Error       string
+	RequestURL  string
+}
+
+// LogApiCall stores an API call log in the database.
+func (d *DB) LogApiCall(ctx context.Context, entry *ApiLogEntry) error {
+	_, err := d.conn.ExecContext(ctx,
+		`INSERT INTO api_logs (username, article_name, status_code, response_time_ms, error, request_url)
+		 VALUES (?, ?, ?, ?, ?, ?)`,
+		entry.Username, entry.ArticleName, entry.StatusCode,
+		entry.ResponseMs, entry.Error, entry.RequestURL,
+	)
+	if err != nil {
+		return fmt.Errorf("log api call: %w", err)
+	}
+	return nil
+}