namecheap: add experimental proxy support (#2715)

.golangci.yml

@@ -216,11 +216,7 @@ linters:
         text: load is a global variable
         linters:
           - gochecknoglobals
-      - path: providers/dns/([\d\w]+/)*[\d\w]+_test.go
-        text: envTest is a global variable
-        linters:
-          - gochecknoglobals
-      - path: providers/http/([\d\w]+/)*[\d\w]+_test.go
+      - path: providers/(dns|http)/([\d\w]+/)*[\d\w]+_test.go
         text: envTest is a global variable
         linters:
           - gochecknoglobals
@@ -228,6 +224,10 @@ linters:
         text: testCases is a global variable
         linters:
           - gochecknoglobals
+      - path: providers/dns/namecheap/transport.go
+        text: (envProxyOnce|envProxyFuncValue) is a global variable
+        linters:
+          - gochecknoglobals
       - path: providers/dns/acmedns/mock_test.go
         text: egTestAccount is a global variable
         linters:

providers/dns/internal/clientdebug/client.go

@@ -91,6 +91,9 @@ func (d *DumpTransport) RoundTrip(h *http.Request) (*http.Response, error) {
 	_, _ = fmt.Fprintln(d.writer, d.redact(data))
 
 	resp, err := d.rt.RoundTrip(h)
+	if err != nil {
+		return nil, err
+	}
 
 	data, _ = httputil.DumpResponse(resp, true)
 

providers/dns/namecheap/namecheap.go

@@ -76,7 +76,8 @@ func NewDefaultConfig() *Config {
 		PropagationTimeout: env.GetOrDefaultSecond(EnvPropagationTimeout, time.Hour),
 		PollingInterval:    env.GetOrDefaultSecond(EnvPollingInterval, 15*time.Second),
 		HTTPClient: &http.Client{
-			Timeout: env.GetOrDefaultSecond(EnvHTTPTimeout, time.Minute),
+			Timeout:   env.GetOrDefaultSecond(EnvHTTPTimeout, time.Minute),
+			Transport: defaultTransport(envNamespace),
 		},
 	}
 }

providers/dns/namecheap/transport.go

@@ -0,0 +1,71 @@
+package namecheap
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+
+	"github.com/go-acme/lego/v4/platform/config/env"
+	"golang.org/x/net/http/httpproxy"
+)
+
+const (
+	envHTTPProxy       = "HTTP_PROXY"
+	envHTTPProxyLower  = "http_proxy"
+	envHTTPSProxy      = "HTTPS_PROXY"
+	envHTTPSProxyLower = "https_proxy"
+	envNoProxy         = "NO_PROXY"
+	envNoProxyLower    = "no_proxy"
+	envRequestMethod   = "REQUEST_METHOD"
+)
+
+// Allows lazy loading of the proxy.
+var (
+	envProxyOnce      sync.Once
+	envProxyFuncValue func(*url.URL) (*url.URL, error)
+)
+
+func defaultTransport(namespace string) http.RoundTripper {
+	tr, ok := http.DefaultTransport.(*http.Transport)
+	if !ok {
+		return nil
+	}
+
+	clone := tr.Clone()
+	clone.Proxy = proxyFromEnvironment(namespace)
+
+	return clone
+}
+
+// Inspired by:
+// - https://pkg.go.dev/net/http#ProxyFromEnvironment
+// - https://pkg.go.dev/golang.org/x/net/http/httpproxy#FromEnvironment
+func envProxyFunc(namespace string) func(*url.URL) (*url.URL, error) {
+	envProxyOnce.Do(func() {
+		cfg := &httpproxy.Config{
+			HTTPProxy:  getEnv(namespace, envHTTPProxy, envHTTPProxyLower),
+			HTTPSProxy: getEnv(namespace, envHTTPSProxy, envHTTPSProxyLower),
+			NoProxy:    getEnv(namespace, envNoProxy, envNoProxyLower),
+			CGI:        env.GetOneWithFallback(namespace+envRequestMethod, "", env.ParseString, envRequestMethod) != "",
+		}
+
+		envProxyFuncValue = cfg.ProxyFunc()
+	})
+
+	return envProxyFuncValue
+}
+
+// Inspired by:
+// - https://pkg.go.dev/net/http#ProxyFromEnvironment
+// - https://pkg.go.dev/golang.org/x/net/http/httpproxy#FromEnvironment
+func proxyFromEnvironment(namespace string) func(req *http.Request) (*url.URL, error) {
+	return func(req *http.Request) (*url.URL, error) {
+		return envProxyFunc(namespace)(req.URL)
+	}
+}
+
+func getEnv(namespace, baseEnvName, baseEnvNameLower string) string {
+	return env.GetOneWithFallback(namespace+baseEnvName, "", env.ParseString,
+		strings.ToLower(namespace)+baseEnvNameLower, baseEnvName, baseEnvNameLower)
+}

providers/dns/namecheap/transport_test.go

@@ -0,0 +1,39 @@
+package namecheap
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/go-acme/lego/v4/platform/tester/servermock"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_defaultTransport(t *testing.T) {
+	client := servermock.NewBuilder(
+		func(server *httptest.Server) (*http.Client, error) {
+			cl := server.Client()
+
+			t.Setenv("NAMECHEAP_HTTP_PROXY", server.URL)
+
+			cl.Transport = defaultTransport(envNamespace)
+
+			return cl, nil
+		}).
+		Route("/",
+			servermock.Noop().WithStatusCode(http.StatusTeapot)).
+		Build(t)
+
+	req, err := http.NewRequest(http.MethodGet, "http://example.com", nil)
+	require.NoError(t, err)
+
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+
+	t.Cleanup(func() {
+		_ = resp.Body.Close()
+	})
+
+	assert.Equal(t, http.StatusTeapot, resp.StatusCode)
+}