Add CORS support and response caching to aggregate endpoints

- Introduced CORS configuration options in config.example.yaml, allowing specification of allowed origins for cross-origin requests. - Enhanced the aggregate handler to support response caching with a configurable TTL, improving performance for repeated requests. - Updated the aggregate API to return a structured response indicating whether any upstream requests failed, enhancing error handling and response clarity. - Modified documentation in AGGREGATE.md and README.md to reflect the new CORS and caching features. - Added tests to validate the new functionality in the aggregate handler.
2026-03-30 10:02:16 +07:00
parent 2a8390e687
commit 04c257a84e
14 changed files with 1071 additions and 142 deletions
@@ -15,105 +15,89 @@ import (

 const statsUsersPath = "stats/users"

-// FetchStatsUsers calls GET {base}{path_prefix}/stats/users for each alias.
+// UpstreamCallMeta describes one upstream Telemt GET outcome (before typed data).
+type UpstreamCallMeta struct {
+	OK         bool   `json:"ok"`
+	HTTPStatus int    `json:"http_status,omitempty"`
+	LatencyMs  int64  `json:"latency_ms,omitempty"`
+	Error      string `json:"error,omitempty"`
+	Revision   string `json:"revision,omitempty"`
+}
+
+type telemtEnvelope[T any] struct {
+	OK       bool   `json:"ok"`
+	Data     T      `json:"data"`
+	Revision string `json:"revision"`
+}
+
+// FetchTelemtGET performs GET {base}{path_prefix}/{relPath} and decodes Telemt success envelope into T.
+// On upstream/network errors, returns zero T and meta with OK=false; meta.Error is set.
+func FetchTelemtGET[T any](ctx context.Context, client *http.Client, parsed *config.Parsed, alias string, relPath string) (out T, meta UpstreamCallMeta) {
+	var zero T
+	srv := parsed.ByAlias[alias]
+	if srv == nil {
+		return zero, UpstreamCallMeta{OK: false, Error: "unknown alias"}
+	}
+	u, err := url.Parse(srv.BaseURL)
+	if err != nil {
+		return zero, UpstreamCallMeta{OK: false, Error: err.Error()}
+	}
+	target := joinPathPrefix(u, srv.PathPrefix, relPath)
+	start := time.Now()
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, target.String(), nil)
+	if err != nil {
+		return zero, UpstreamCallMeta{OK: false, LatencyMs: time.Since(start).Milliseconds(), Error: err.Error()}
+	}
+	if auth := parsed.AuthByAlias[alias]; auth != "" {
+		req.Header.Set("Authorization", auth)
+	}
+	resp, err := client.Do(req)
+	latency := time.Since(start).Milliseconds()
+	if err != nil {
+		return zero, UpstreamCallMeta{OK: false, LatencyMs: latency, Error: err.Error()}
+	}
+	body, readErr := io.ReadAll(io.LimitReader(resp.Body, 64<<20))
+	_ = resp.Body.Close()
+	if readErr != nil {
+		return zero, UpstreamCallMeta{OK: false, HTTPStatus: resp.StatusCode, LatencyMs: latency, Error: readErr.Error()}
+	}
+	if resp.StatusCode != http.StatusOK {
+		return zero, UpstreamCallMeta{
+			OK: false, HTTPStatus: resp.StatusCode, LatencyMs: latency,
+			Error: fmt.Sprintf("http %d: %s", resp.StatusCode, truncate(string(body), 200)),
+		}
+	}
+	var env telemtEnvelope[json.RawMessage]
+	if err := json.Unmarshal(body, &env); err != nil {
+		return zero, UpstreamCallMeta{OK: false, HTTPStatus: resp.StatusCode, LatencyMs: latency, Error: "invalid json: " + err.Error()}
+	}
+	if !env.OK {
+		return zero, UpstreamCallMeta{OK: false, HTTPStatus: resp.StatusCode, LatencyMs: latency, Error: "upstream ok=false"}
+	}
+	var data T
+	if err := json.Unmarshal(env.Data, &data); err != nil {
+		return zero, UpstreamCallMeta{OK: false, HTTPStatus: resp.StatusCode, LatencyMs: latency, Error: "decode data: " + err.Error()}
+	}
+	return data, UpstreamCallMeta{OK: true, HTTPStatus: resp.StatusCode, LatencyMs: latency, Revision: env.Revision}
+}
+
+// FetchStatsUsers calls GET stats/users for each alias using FetchTelemtGET.
 func FetchStatsUsers(ctx context.Context, client *http.Client, parsed *config.Parsed, aliases []string) []ServerFetchResult {
 	out := make([]ServerFetchResult, 0, len(aliases))
 	for _, alias := range aliases {
-		srv := parsed.ByAlias[alias]
-		if srv == nil {
-			out = append(out, ServerFetchResult{
-				Alias: alias,
-				OK:    false,
-				Error: "unknown alias",
-			})
-			continue
-		}
-		u, err := url.Parse(srv.BaseURL)
-		if err != nil {
-			out = append(out, ServerFetchResult{
-				Alias: alias,
-				OK:    false,
-				Error: err.Error(),
-			})
-			continue
-		}
-		target := joinPathPrefix(u, srv.PathPrefix, statsUsersPath)
-		start := time.Now()
-		req, err := http.NewRequestWithContext(ctx, http.MethodGet, target.String(), nil)
-		if err != nil {
-			out = append(out, ServerFetchResult{
-				Alias:     alias,
-				OK:        false,
-				LatencyMs: time.Since(start).Milliseconds(),
-				Error:     err.Error(),
-			})
-			continue
-		}
-		if auth := parsed.AuthByAlias[alias]; auth != "" {
-			req.Header.Set("Authorization", auth)
-		}
-		resp, err := client.Do(req)
-		latency := time.Since(start).Milliseconds()
-		if err != nil {
-			out = append(out, ServerFetchResult{
-				Alias:     alias,
-				OK:        false,
-				LatencyMs: latency,
-				Error:     err.Error(),
-			})
-			continue
-		}
-		body, readErr := io.ReadAll(io.LimitReader(resp.Body, 64<<20))
-		_ = resp.Body.Close()
-		if readErr != nil {
-			out = append(out, ServerFetchResult{
-				Alias:      alias,
-				OK:         false,
-				HTTPStatus: resp.StatusCode,
-				LatencyMs:  latency,
-				Error:      readErr.Error(),
-			})
-			continue
-		}
-		if resp.StatusCode != http.StatusOK {
-			out = append(out, ServerFetchResult{
-				Alias:      alias,
-				OK:         false,
-				HTTPStatus: resp.StatusCode,
-				LatencyMs:  latency,
-				Error:      fmt.Sprintf("http %d: %s", resp.StatusCode, truncate(string(body), 200)),
-			})
-			continue
-		}
-		var env statsUsersEnvelope
-		if err := json.Unmarshal(body, &env); err != nil {
-			out = append(out, ServerFetchResult{
-				Alias:      alias,
-				OK:         false,
-				HTTPStatus: resp.StatusCode,
-				LatencyMs:  latency,
-				Error:      "invalid json: " + err.Error(),
-			})
-			continue
-		}
-		if !env.OK {
-			out = append(out, ServerFetchResult{
-				Alias:      alias,
-				OK:         false,
-				HTTPStatus: resp.StatusCode,
-				LatencyMs:  latency,
-				Error:      "upstream ok=false",
-			})
-			continue
-		}
-		out = append(out, ServerFetchResult{
+		users, meta := FetchTelemtGET[[]UserInfo](ctx, client, parsed, alias, statsUsersPath)
+		fr := ServerFetchResult{
 			Alias:      alias,
-			OK:         true,
-			HTTPStatus: resp.StatusCode,
-			LatencyMs:  latency,
-			Revision:   env.Revision,
-			Users:      env.Data,
-		})
+			OK:         meta.OK,
+			HTTPStatus: meta.HTTPStatus,
+			LatencyMs:  meta.LatencyMs,
+			Error:      meta.Error,
+			Revision:   meta.Revision,
+		}
+		if meta.OK {
+			fr.Users = users
+		}
+		out = append(out, fr)
 	}
 	return out
 }