--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+ "bytes"
+ "context"
+ "crypto"
+ "crypto/rand"
+ "encoding/json"
+ "fmt"
+ "io/ioutil"
+ "math/big"
+ "net/http"
+ "strconv"
+ "strings"
+ "time"
+)
+
+// retryTimer encapsulates common logic for retrying unsuccessful requests.
+// It is not safe for concurrent use.
+type retryTimer struct {
+ // backoffFn provides backoff delay sequence for retries.
+ // See Client.RetryBackoff doc comment.
+ backoffFn func(n int, r *http.Request, res *http.Response) time.Duration
+ // n is the current retry attempt.
+ n int
+}
+
+func (t *retryTimer) inc() {
+ t.n++
+}
+
+// backoff pauses the current goroutine as described in Client.RetryBackoff.
+func (t *retryTimer) backoff(ctx context.Context, r *http.Request, res *http.Response) error {
+ d := t.backoffFn(t.n, r, res)
+ if d <= 0 {
+ return fmt.Errorf("acme: no more retries for %s; tried %d time(s)", r.URL, t.n)
+ }
+ wakeup := time.NewTimer(d)
+ defer wakeup.Stop()
+ select {
+ case <-ctx.Done():
+ return ctx.Err()
+ case <-wakeup.C:
+ return nil
+ }
+}
+
+func (c *Client) retryTimer() *retryTimer {
+ f := c.RetryBackoff
+ if f == nil {
+ f = defaultBackoff
+ }
+ return &retryTimer{backoffFn: f}
+}
+
+// defaultBackoff provides default Client.RetryBackoff implementation
+// using a truncated exponential backoff algorithm,
+// as described in Client.RetryBackoff.
+//
+// The n argument is always bounded between 1 and 30.
+// The returned value is always greater than 0.
+func defaultBackoff(n int, r *http.Request, res *http.Response) time.Duration {
+ const max = 10 * time.Second
+ var jitter time.Duration
+ if x, err := rand.Int(rand.Reader, big.NewInt(1000)); err == nil {
+ // Set the minimum to 1ms to avoid a case where
+ // an invalid Retry-After value is parsed into 0 below,
+ // resulting in the 0 returned value which would unintentionally
+ // stop the retries.
+ jitter = (1 + time.Duration(x.Int64())) * time.Millisecond
+ }
+ if v, ok := res.Header["Retry-After"]; ok {
+ return retryAfter(v[0]) + jitter
+ }
+
+ if n < 1 {
+ n = 1
+ }
+ if n > 30 {
+ n = 30
+ }
+ d := time.Duration(1<<uint(n-1))*time.Second + jitter
+ if d > max {
+ return max
+ }
+ return d
+}
+
+// retryAfter parses a Retry-After HTTP header value,
+// trying to convert v into an int (seconds) or use http.ParseTime otherwise.
+// It returns zero value if v cannot be parsed.
+func retryAfter(v string) time.Duration {
+ if i, err := strconv.Atoi(v); err == nil {
+ return time.Duration(i) * time.Second
+ }
+ t, err := http.ParseTime(v)
+ if err != nil {
+ return 0
+ }
+ return t.Sub(timeNow())
+}
+
+// resOkay is a function that reports whether the provided response is okay.
+// It is expected to keep the response body unread.
+type resOkay func(*http.Response) bool
+
+// wantStatus returns a function which reports whether the code
+// matches the status code of a response.
+func wantStatus(codes ...int) resOkay {
+ return func(res *http.Response) bool {
+ for _, code := range codes {
+ if code == res.StatusCode {
+ return true
+ }
+ }
+ return false
+ }
+}
+
+// get issues an unsigned GET request to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// get retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+func (c *Client) get(ctx context.Context, url string, ok resOkay) (*http.Response, error) {
+ retry := c.retryTimer()
+ for {
+ req, err := http.NewRequest("GET", url, nil)
+ if err != nil {
+ return nil, err
+ }
+ res, err := c.doNoRetry(ctx, req)
+ switch {
+ case err != nil:
+ return nil, err
+ case ok(res):
+ return res, nil
+ case isRetriable(res.StatusCode):
+ retry.inc()
+ resErr := responseError(res)
+ res.Body.Close()
+ // Ignore the error value from retry.backoff
+ // and return the one from last retry, as received from the CA.
+ if retry.backoff(ctx, req, res) != nil {
+ return nil, resErr
+ }
+ default:
+ defer res.Body.Close()
+ return nil, responseError(res)
+ }
+ }
+}
+
+// post issues a signed POST request in JWS format using the provided key
+// to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// post retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+// It uses postNoRetry to make individual requests.
+func (c *Client) post(ctx context.Context, key crypto.Signer, url string, body interface{}, ok resOkay) (*http.Response, error) {
+ retry := c.retryTimer()
+ for {
+ res, req, err := c.postNoRetry(ctx, key, url, body)
+ if err != nil {
+ return nil, err
+ }
+ if ok(res) {
+ return res, nil
+ }
+ resErr := responseError(res)
+ res.Body.Close()
+ switch {
+ // Check for bad nonce before isRetriable because it may have been returned
+ // with an unretriable response code such as 400 Bad Request.
+ case isBadNonce(resErr):
+ // Consider any previously stored nonce values to be invalid.
+ c.clearNonces()
+ case !isRetriable(res.StatusCode):
+ return nil, resErr
+ }
+ retry.inc()
+ // Ignore the error value from retry.backoff
+ // and return the one from last retry, as received from the CA.
+ if err := retry.backoff(ctx, req, res); err != nil {
+ return nil, resErr
+ }
+ }
+}
+
+// postNoRetry signs the body with the given key and POSTs it to the provided url.
+// The body argument must be JSON-serializable.
+// It is used by c.post to retry unsuccessful attempts.
+func (c *Client) postNoRetry(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, *http.Request, error) {
+ nonce, err := c.popNonce(ctx, url)
+ if err != nil {
+ return nil, nil, err
+ }
+ b, err := jwsEncodeJSON(body, key, nonce)
+ if err != nil {
+ return nil, nil, err
+ }
+ req, err := http.NewRequest("POST", url, bytes.NewReader(b))
+ if err != nil {
+ return nil, nil, err
+ }
+ req.Header.Set("Content-Type", "application/jose+json")
+ res, err := c.doNoRetry(ctx, req)
+ if err != nil {
+ return nil, nil, err
+ }
+ c.addNonce(res.Header)
+ return res, req, nil
+}
+
+// doNoRetry issues a request req, replacing its context (if any) with ctx.
+func (c *Client) doNoRetry(ctx context.Context, req *http.Request) (*http.Response, error) {
+ res, err := c.httpClient().Do(req.WithContext(ctx))
+ if err != nil {
+ select {
+ case <-ctx.Done():
+ // Prefer the unadorned context error.
+ // (The acme package had tests assuming this, previously from ctxhttp's
+ // behavior, predating net/http supporting contexts natively)
+ // TODO(bradfitz): reconsider this in the future. But for now this
+ // requires no test updates.
+ return nil, ctx.Err()
+ default:
+ return nil, err
+ }
+ }
+ return res, nil
+}
+
+func (c *Client) httpClient() *http.Client {
+ if c.HTTPClient != nil {
+ return c.HTTPClient
+ }
+ return http.DefaultClient
+}
+
+// isBadNonce reports whether err is an ACME "badnonce" error.
+func isBadNonce(err error) bool {
+ // According to the spec badNonce is urn:ietf:params:acme:error:badNonce.
+ // However, ACME servers in the wild return their versions of the error.
+ // See https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-5.4
+ // and https://github.com/letsencrypt/boulder/blob/0e07eacb/docs/acme-divergences.md#section-66.
+ ae, ok := err.(*Error)
+ return ok && strings.HasSuffix(strings.ToLower(ae.ProblemType), ":badnonce")
+}
+
+// isRetriable reports whether a request can be retried
+// based on the response status code.
+//
+// Note that a "bad nonce" error is returned with a non-retriable 400 Bad Request code.
+// Callers should parse the response and check with isBadNonce.
+func isRetriable(code int) bool {
+ return code <= 399 || code >= 500 || code == http.StatusTooManyRequests
+}
+
+// responseError creates an error of Error type from resp.
+func responseError(resp *http.Response) error {
+ // don't care if ReadAll returns an error:
+ // json.Unmarshal will fail in that case anyway
+ b, _ := ioutil.ReadAll(resp.Body)
+ e := &wireError{Status: resp.StatusCode}
+ if err := json.Unmarshal(b, e); err != nil {
+ // this is not a regular error response:
+ // populate detail with anything we received,
+ // e.Status will already contain HTTP response code value
+ e.Detail = string(b)
+ if e.Detail == "" {
+ e.Detail = resp.Status
+ }
+ }
+ return e.error(resp.Header)
+}
Code Review / barometer.git / blobdiff