proxy.go

v1.0.0

package server

import (
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"

	"golang.org/x/mod/module"

	"example.com/curator/internal/build"
	"example.com/curator/internal/git"
	"example.com/curator/internal/metrics"
	"example.com/curator/internal/storage"
)

func (s *Server) serveProxy(w http.ResponseWriter, r *http.Request, escapedModPath, file string) {
	// Unescape the module path (e.g., "!azure" → "Azure").
	modPath, err := module.UnescapePath(escapedModPath)
	if err != nil {
		log.Printf("proxy: invalid module path %q: %v", escapedModPath, err)
		http.NotFound(w, r)
		return
	}

	localName := modPath
	if strings.Contains(modPath, "/") {
		if after, ok := strings.CutPrefix(modPath, s.Cfg.Host+"/"); ok {
			localName = after
		}
	}

	if _, ok := s.Resolver.ResolveModule(localName); ok {
		if !s.CanAccessModule(localName, r) {
			http.NotFound(w, r)
			return
		}

		s.serveLocalModule(w, r, localName, file)
		return
	}

	s.serveFallback(w, r, escapedModPath, file)
}

func (s *Server) serveLocalModule(w http.ResponseWriter, r *http.Request, modName, file string) {
	mod, _ := s.Resolver.ResolveModule(modName)
	modulePath := s.Cfg.Host + "/" + modName

	// For version-specific artifacts, try S3 cache first.
	if s.Store != nil && file != "list" {
		key := StorageKey(modName, file)
		data, ct, err := s.Store.Get(r.Context(), key)
		if err == nil {
			metrics.ProxyCacheHitsTotal.Inc()
			w.Header().Set("Content-Type", ct)
			w.Write(data)
			return
		}

		metrics.ProxyCacheMissesTotal.Inc()
		if !errors.Is(err, storage.ErrNotFound) {
			log.Printf("s3 get %s: %v", key, err)
		}
	}

	repoPath, err := s.Git.CloneOrFetch(modName, mod.Repo)
	if err != nil {
		log.Printf("git error for %s: %v", modName, err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	switch {
	case file == "list":
		s.serveList(w, repoPath, modulePath)
	case strings.HasSuffix(file, ".info"):
		escapedVer := strings.TrimSuffix(file, ".info")
		query, err := module.UnescapeVersion(escapedVer)
		if err != nil {
			log.Printf("proxy: invalid version %q: %v", escapedVer, err)
			http.NotFound(w, r)
			return
		}
		rv, err := git.ResolveVersion(repoPath, query)
		if err != nil {
			log.Printf("resolve %s: %v", query, err)
			http.NotFound(w, r)
			return
		}
		cacheFile := rv.Version + ".info"
		s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
			return build.Info(repoPath, rv, modulePath)
		})
	case strings.HasSuffix(file, ".mod"):
		escapedVer := strings.TrimSuffix(file, ".mod")
		query, err := module.UnescapeVersion(escapedVer)
		if err != nil {
			log.Printf("proxy: invalid version %q: %v", escapedVer, err)
			http.NotFound(w, r)
			return
		}
		rv, err := git.ResolveVersion(repoPath, query)
		if err != nil {
			log.Printf("resolve %s: %v", query, err)
			http.NotFound(w, r)
			return
		}
		cacheFile := rv.Version + ".mod"
		s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
			return build.Mod(repoPath, rv, modulePath)
		})
	case strings.HasSuffix(file, ".zip"):
		escapedVer := strings.TrimSuffix(file, ".zip")
		query, err := module.UnescapeVersion(escapedVer)
		if err != nil {
			log.Printf("proxy: invalid version %q: %v", escapedVer, err)
			http.NotFound(w, r)
			return
		}
		rv, err := git.ResolveVersion(repoPath, query)
		if err != nil {
			log.Printf("resolve %s: %v", query, err)
			http.NotFound(w, r)
			return
		}
		cacheFile := rv.Version + ".zip"
		s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
			return build.Zip(repoPath, rv, modulePath)
		})
	default:
		http.NotFound(w, r)
	}
}

// serveLatest handles GET $base/$module/@latest requests.
func (s *Server) serveLatest(w http.ResponseWriter, r *http.Request, escapedModPath string) {
	modPath, err := module.UnescapePath(escapedModPath)
	if err != nil {
		log.Printf("proxy: invalid module path %q: %v", escapedModPath, err)
		http.NotFound(w, r)
		return
	}

	localName := modPath
	if strings.Contains(modPath, "/") {
		if after, ok := strings.CutPrefix(modPath, s.Cfg.Host+"/"); ok {
			localName = after
		}
	}

	mod, ok := s.Resolver.ResolveModule(localName)
	if !ok {
		// Try fallback for @latest.
		s.serveFallbackLatest(w, r, escapedModPath)
		return
	}

	if !s.CanAccessModule(localName, r) {
		http.NotFound(w, r)
		return
	}

	modulePath := s.Cfg.Host + "/" + localName

	repoPath, err := s.Git.CloneOrFetch(localName, mod.Repo)
	if err != nil {
		log.Printf("git error for %s: %v", localName, err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	allTags, err := git.ListTags(repoPath)
	if err != nil || len(allTags) == 0 {
		http.NotFound(w, r)
		return
	}

	tags := git.FilterTagsByMajor(allTags, modulePath)
	if len(tags) == 0 {
		http.NotFound(w, r)
		return
	}

	latest := git.LatestRelease(tags)
	rv, err := git.ResolveVersion(repoPath, latest)
	if err != nil {
		log.Printf("resolve latest %s: %v", latest, err)
		http.NotFound(w, r)
		return
	}

	data, ct, err := build.Info(repoPath, rv, modulePath)
	if err != nil {
		log.Printf("build info for %s@latest: %v", localName, err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", ct)
	w.Write(data)
}

func (s *Server) serveFallback(w http.ResponseWriter, r *http.Request, modName, file string) {
	mode := s.Cfg.FallbackMode()
	switch mode {
	case "redirect":
		http.Redirect(w, r, s.upstreamURL(modName, file), http.StatusFound)
	case "sync":
		s.fetchAndCache(w, r, modName, file, true)
	case "async":
		s.fetchAndCache(w, r, modName, file, false)
	default:
		http.NotFound(w, r)
	}
}

func (s *Server) serveFallbackLatest(w http.ResponseWriter, r *http.Request, modName string) {
	mode := s.Cfg.FallbackMode()
	upURL := strings.TrimRight(s.Cfg.Fallback.Upstream, "/") + "/" + modName + "/@latest"

	switch mode {
	case "redirect":
		http.Redirect(w, r, upURL, http.StatusFound)
	case "sync", "async":
		req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, upURL, nil)
		if err != nil {
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		resp, err := s.HTTPClient.Do(req)
		if err != nil {
			http.Error(w, "upstream error", http.StatusBadGateway)
			return
		}
		defer resp.Body.Close()
		w.WriteHeader(resp.StatusCode)
		io.Copy(w, resp.Body)
	default:
		http.NotFound(w, r)
	}
}

func (s *Server) upstreamURL(modName, file string) string {
	return strings.TrimRight(s.Cfg.Fallback.Upstream, "/") + "/" + modName + "/@v/" + file
}

// fetchAndCache fetches from upstream and optionally caches.
// When syncCache is true (sync mode), the cache write completes before responding.
// When false (async mode), the cache write runs in a background goroutine.
func (s *Server) fetchAndCache(w http.ResponseWriter, r *http.Request, modName, file string, syncCache bool) {
	// Try cache first for both sync and async modes.
	if s.Store != nil {
		key := StorageKey(modName, file)
		data, ct, err := s.Store.Get(r.Context(), key)
		if err == nil {
			metrics.ProxyCacheHitsTotal.Inc()
			w.Header().Set("Content-Type", ct)
			w.Write(data)
			return
		}

		if !errors.Is(err, storage.ErrNotFound) {
			log.Printf("storage get %s: %v", key, err)
		}
	}

	upURL := s.upstreamURL(modName, file)

	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, upURL, nil)
	if err != nil {
		log.Printf("upstream request: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	resp, err := s.HTTPClient.Do(req)
	if err != nil {
		log.Printf("upstream fetch %s: %v", upURL, err)
		http.Error(w, "upstream error", http.StatusBadGateway)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		w.WriteHeader(resp.StatusCode)
		io.Copy(w, resp.Body)
		return
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		log.Printf("upstream read %s: %v", upURL, err)
		http.Error(w, "upstream error", http.StatusBadGateway)
		return
	}

	ct := resp.Header.Get("Content-Type")

	if s.Store != nil {
		key := StorageKey(modName, file)
		if syncCache {
			if err := s.Store.Put(context.Background(), key, body, ct); err != nil {
				log.Printf("storage put %s: %v", key, err)
			}
		} else {
			go func() {
				if err := s.Store.Put(context.Background(), key, body, ct); err != nil {
					log.Printf("storage put %s: %v", key, err)
				}
			}()
		}
	}

	if ct != "" {
		w.Header().Set("Content-Type", ct)
	}

	w.Write(body)
}

func (s *Server) serveVersioned(w http.ResponseWriter, r *http.Request, modName, file string, buildFn func() ([]byte, string, error)) {
	data, ct, err := buildFn()
	if err != nil {
		log.Printf("build %s/%s: %v", modName, file, err)
		http.NotFound(w, nil)
		return
	}

	if s.Store != nil {
		key := StorageKey(modName, file)
		go func() {
			if err := s.Store.Put(context.Background(), key, data, ct); err != nil {
				log.Printf("s3 put %s: %v", key, err)
			}
		}()
	}

	w.Header().Set("Content-Type", ct)
	w.Write(data)
}

func (s *Server) serveList(w http.ResponseWriter, repoPath, modulePath string) {
	tags, err := git.ListTags(repoPath)
	if err != nil {
		log.Printf("list tags: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	tags = git.FilterTagsByMajor(tags, modulePath)

	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	for _, tag := range tags {
		_, t, err := git.CommitInfo(repoPath, tag)
		if err != nil {
			// Fall back to version only (no timestamp).
			fmt.Fprintln(w, tag)
			continue
		}
		fmt.Fprintf(w, "%s %s\n", tag, t.UTC().Format("2006-01-02T15:04:05Z"))
	}
}


1	package server
2
3	import (
4	"context"
5	"errors"
6	"fmt"
7	"io"
8	"log"
9	"net/http"
10	"strings"
11
12	"golang.org/x/mod/module"
13
14	"example.com/curator/internal/build"
15	"example.com/curator/internal/git"
16	"example.com/curator/internal/metrics"
17	"example.com/curator/internal/storage"
18	)
19
20	func (s Server) serveProxy(w http.ResponseWriter, r http.Request, escapedModPath, file string) {
21	// Unescape the module path (e.g., "!azure" → "Azure").
22	modPath, err := module.UnescapePath(escapedModPath)
23	if err != nil {
24	log.Printf("proxy: invalid module path %q: %v", escapedModPath, err)
25	http.NotFound(w, r)
26	return
27	}
28
29	localName := modPath
30	if strings.Contains(modPath, "/") {
31	if after, ok := strings.CutPrefix(modPath, s.Cfg.Host+"/"); ok {
32	localName = after
33	}
34	}
35
36	if _, ok := s.Resolver.ResolveModule(localName); ok {
37	if !s.CanAccessModule(localName, r) {
38	http.NotFound(w, r)
39	return
40	}
41
42	s.serveLocalModule(w, r, localName, file)
43	return
44	}
45
46	s.serveFallback(w, r, escapedModPath, file)
47	}
48
49	func (s Server) serveLocalModule(w http.ResponseWriter, r http.Request, modName, file string) {
50	mod, _ := s.Resolver.ResolveModule(modName)
51	modulePath := s.Cfg.Host + "/" + modName
52
53	// For version-specific artifacts, try S3 cache first.
54	if s.Store != nil && file != "list" {
55	key := StorageKey(modName, file)
56	data, ct, err := s.Store.Get(r.Context(), key)
57	if err == nil {
58	metrics.ProxyCacheHitsTotal.Inc()
59	w.Header().Set("Content-Type", ct)
60	w.Write(data)
61	return
62	}
63
64	metrics.ProxyCacheMissesTotal.Inc()
65	if !errors.Is(err, storage.ErrNotFound) {
66	log.Printf("s3 get %s: %v", key, err)
67	}
68	}
69
70	repoPath, err := s.Git.CloneOrFetch(modName, mod.Repo)
71	if err != nil {
72	log.Printf("git error for %s: %v", modName, err)
73	http.Error(w, "internal error", http.StatusInternalServerError)
74	return
75	}
76
77	switch {
78	case file == "list":
79	s.serveList(w, repoPath, modulePath)
80	case strings.HasSuffix(file, ".info"):
81	escapedVer := strings.TrimSuffix(file, ".info")
82	query, err := module.UnescapeVersion(escapedVer)
83	if err != nil {
84	log.Printf("proxy: invalid version %q: %v", escapedVer, err)
85	http.NotFound(w, r)
86	return
87	}
88	rv, err := git.ResolveVersion(repoPath, query)
89	if err != nil {
90	log.Printf("resolve %s: %v", query, err)
91	http.NotFound(w, r)
92	return
93	}
94	cacheFile := rv.Version + ".info"
95	s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
96	return build.Info(repoPath, rv, modulePath)
97	})
98	case strings.HasSuffix(file, ".mod"):
99	escapedVer := strings.TrimSuffix(file, ".mod")
100	query, err := module.UnescapeVersion(escapedVer)
101	if err != nil {
102	log.Printf("proxy: invalid version %q: %v", escapedVer, err)
103	http.NotFound(w, r)
104	return
105	}
106	rv, err := git.ResolveVersion(repoPath, query)
107	if err != nil {
108	log.Printf("resolve %s: %v", query, err)
109	http.NotFound(w, r)
110	return
111	}
112	cacheFile := rv.Version + ".mod"
113	s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
114	return build.Mod(repoPath, rv, modulePath)
115	})
116	case strings.HasSuffix(file, ".zip"):
117	escapedVer := strings.TrimSuffix(file, ".zip")
118	query, err := module.UnescapeVersion(escapedVer)
119	if err != nil {
120	log.Printf("proxy: invalid version %q: %v", escapedVer, err)
121	http.NotFound(w, r)
122	return
123	}
124	rv, err := git.ResolveVersion(repoPath, query)
125	if err != nil {
126	log.Printf("resolve %s: %v", query, err)
127	http.NotFound(w, r)
128	return
129	}
130	cacheFile := rv.Version + ".zip"
131	s.serveVersioned(w, r, modName, cacheFile, func() ([]byte, string, error) {
132	return build.Zip(repoPath, rv, modulePath)
133	})
134	default:
135	http.NotFound(w, r)
136	}
137	}
138
139	// serveLatest handles GET $base/$module/@latest requests.
140	func (s Server) serveLatest(w http.ResponseWriter, r http.Request, escapedModPath string) {
141	modPath, err := module.UnescapePath(escapedModPath)
142	if err != nil {
143	log.Printf("proxy: invalid module path %q: %v", escapedModPath, err)
144	http.NotFound(w, r)
145	return
146	}
147
148	localName := modPath
149	if strings.Contains(modPath, "/") {
150	if after, ok := strings.CutPrefix(modPath, s.Cfg.Host+"/"); ok {
151	localName = after
152	}
153	}
154
155	mod, ok := s.Resolver.ResolveModule(localName)
156	if !ok {
157	// Try fallback for @latest.
158	s.serveFallbackLatest(w, r, escapedModPath)
159	return
160	}
161
162	if !s.CanAccessModule(localName, r) {
163	http.NotFound(w, r)
164	return
165	}
166
167	modulePath := s.Cfg.Host + "/" + localName
168
169	repoPath, err := s.Git.CloneOrFetch(localName, mod.Repo)
170	if err != nil {
171	log.Printf("git error for %s: %v", localName, err)
172	http.Error(w, "internal error", http.StatusInternalServerError)
173	return
174	}
175
176	allTags, err := git.ListTags(repoPath)
177	if err != nil \|\| len(allTags) == 0 {
178	http.NotFound(w, r)
179	return
180	}
181
182	tags := git.FilterTagsByMajor(allTags, modulePath)
183	if len(tags) == 0 {
184	http.NotFound(w, r)
185	return
186	}
187
188	latest := git.LatestRelease(tags)
189	rv, err := git.ResolveVersion(repoPath, latest)
190	if err != nil {
191	log.Printf("resolve latest %s: %v", latest, err)
192	http.NotFound(w, r)
193	return
194	}
195
196	data, ct, err := build.Info(repoPath, rv, modulePath)
197	if err != nil {
198	log.Printf("build info for %s@latest: %v", localName, err)
199	http.Error(w, "internal error", http.StatusInternalServerError)
200	return
201	}
202
203	w.Header().Set("Content-Type", ct)
204	w.Write(data)
205	}
206
207	func (s Server) serveFallback(w http.ResponseWriter, r http.Request, modName, file string) {
208	mode := s.Cfg.FallbackMode()
209	switch mode {
210	case "redirect":
211	http.Redirect(w, r, s.upstreamURL(modName, file), http.StatusFound)
212	case "sync":
213	s.fetchAndCache(w, r, modName, file, true)
214	case "async":
215	s.fetchAndCache(w, r, modName, file, false)
216	default:
217	http.NotFound(w, r)
218	}
219	}
220
221	func (s Server) serveFallbackLatest(w http.ResponseWriter, r http.Request, modName string) {
222	mode := s.Cfg.FallbackMode()
223	upURL := strings.TrimRight(s.Cfg.Fallback.Upstream, "/") + "/" + modName + "/@latest"
224
225	switch mode {
226	case "redirect":
227	http.Redirect(w, r, upURL, http.StatusFound)
228	case "sync", "async":
229	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, upURL, nil)
230	if err != nil {
231	http.Error(w, "internal error", http.StatusInternalServerError)
232	return
233	}
234	resp, err := s.HTTPClient.Do(req)
235	if err != nil {
236	http.Error(w, "upstream error", http.StatusBadGateway)
237	return
238	}
239	defer resp.Body.Close()
240	w.WriteHeader(resp.StatusCode)
241	io.Copy(w, resp.Body)
242	default:
243	http.NotFound(w, r)
244	}
245	}
246
247	func (s *Server) upstreamURL(modName, file string) string {
248	return strings.TrimRight(s.Cfg.Fallback.Upstream, "/") + "/" + modName + "/@v/" + file
249	}
250
251	// fetchAndCache fetches from upstream and optionally caches.
252	// When syncCache is true (sync mode), the cache write completes before responding.
253	// When false (async mode), the cache write runs in a background goroutine.
254	func (s Server) fetchAndCache(w http.ResponseWriter, r http.Request, modName, file string, syncCache bool) {
255	// Try cache first for both sync and async modes.
256	if s.Store != nil {
257	key := StorageKey(modName, file)
258	data, ct, err := s.Store.Get(r.Context(), key)
259	if err == nil {
260	metrics.ProxyCacheHitsTotal.Inc()
261	w.Header().Set("Content-Type", ct)
262	w.Write(data)
263	return
264	}
265
266	if !errors.Is(err, storage.ErrNotFound) {
267	log.Printf("storage get %s: %v", key, err)
268	}
269	}
270
271	upURL := s.upstreamURL(modName, file)
272
273	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, upURL, nil)
274	if err != nil {
275	log.Printf("upstream request: %v", err)
276	http.Error(w, "internal error", http.StatusInternalServerError)
277	return
278	}
279
280	resp, err := s.HTTPClient.Do(req)
281	if err != nil {
282	log.Printf("upstream fetch %s: %v", upURL, err)
283	http.Error(w, "upstream error", http.StatusBadGateway)
284	return
285	}
286	defer resp.Body.Close()
287
288	if resp.StatusCode != http.StatusOK {
289	w.WriteHeader(resp.StatusCode)
290	io.Copy(w, resp.Body)
291	return
292	}
293
294	body, err := io.ReadAll(resp.Body)
295	if err != nil {
296	log.Printf("upstream read %s: %v", upURL, err)
297	http.Error(w, "upstream error", http.StatusBadGateway)
298	return
299	}
300
301	ct := resp.Header.Get("Content-Type")
302
303	if s.Store != nil {
304	key := StorageKey(modName, file)
305	if syncCache {
306	if err := s.Store.Put(context.Background(), key, body, ct); err != nil {
307	log.Printf("storage put %s: %v", key, err)
308	}
309	} else {
310	go func() {
311	if err := s.Store.Put(context.Background(), key, body, ct); err != nil {
312	log.Printf("storage put %s: %v", key, err)
313	}
314	}()
315	}
316	}
317
318	if ct != "" {
319	w.Header().Set("Content-Type", ct)
320	}
321
322	w.Write(body)
323	}
324
325	func (s Server) serveVersioned(w http.ResponseWriter, r http.Request, modName, file string, buildFn func() ([]byte, string, error)) {
326	data, ct, err := buildFn()
327	if err != nil {
328	log.Printf("build %s/%s: %v", modName, file, err)
329	http.NotFound(w, nil)
330	return
331	}
332
333	if s.Store != nil {
334	key := StorageKey(modName, file)
335	go func() {
336	if err := s.Store.Put(context.Background(), key, data, ct); err != nil {
337	log.Printf("s3 put %s: %v", key, err)
338	}
339	}()
340	}
341
342	w.Header().Set("Content-Type", ct)
343	w.Write(data)
344	}
345
346	func (s *Server) serveList(w http.ResponseWriter, repoPath, modulePath string) {
347	tags, err := git.ListTags(repoPath)
348	if err != nil {
349	log.Printf("list tags: %v", err)
350	http.Error(w, "internal error", http.StatusInternalServerError)
351	return
352	}
353
354	tags = git.FilterTagsByMajor(tags, modulePath)
355
356	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
357	for _, tag := range tags {
358	_, t, err := git.CommitInfo(repoPath, tag)
359	if err != nil {
360	// Fall back to version only (no timestamp).
361	fmt.Fprintln(w, tag)
362	continue
363	}
364	fmt.Fprintf(w, "%s %s\n", tag, t.UTC().Format("2006-01-02T15:04:05Z"))
365	}
366	}
367

proxy.go

Source Files