7491: Remove KeepServerError, all errors are BlockNotFound errors for now.

Refactor Get() and Ask() to use common function.

diff --git a/sdk/go/keepclient/keepclient.go b/sdk/go/keepclient/keepclient.go
index 2cf852b8f7071204472febe15001677318ae1d39..26764e5ce420c0a7df763df654e824ebda5c889d 100644 (file)
--- a/sdk/go/keepclient/keepclient.go
+++ b/sdk/go/keepclient/keepclient.go
@@ -29,7 +29,6 @@ var OversizeBlockError = errors.New("Exceeded maximum block size (" + strconv.It
 var MissingArvadosApiHost = errors.New("Missing required environment variable ARVADOS_API_HOST")
 var MissingArvadosApiToken = errors.New("Missing required environment variable ARVADOS_API_TOKEN")
 var InvalidLocatorError = errors.New("Invalid locator")
-var KeepServerError = errors.New("One or more keep servers returned an error")
 
 // ErrNoSuchKeepServer is returned when GetIndex is invoked with a UUID with no matching keep server
 var ErrNoSuchKeepServer = errors.New("No keep server matching the given UUID is found")
@@ -140,14 +139,7 @@ func (kc *KeepClient) PutR(r io.Reader) (locator string, replicas int, err error
        }
 }
 
-// Get() retrieves a block, given a locator. Returns a reader, the
-// expected data length, the URL the block is being fetched from, and
-// an error.
-//
-// If the block checksum does not match, the final Read() on the
-// reader returned by this method will return a BadChecksum error
-// instead of EOF.
-func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error) {
+func (kc *KeepClient) getOrHead(method string, locator string) (io.ReadCloser, int64, string, error) {
        var errs []string
 
        tries_remaining := 1 + kc.Retries
@@ -161,7 +153,7 @@ func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error)
                for _, host := range serversToTry {
                        url := host + "/" + locator
 
-                       req, err := http.NewRequest("GET", url, nil)
+                       req, err := http.NewRequest(method, url, nil)
                        if err != nil {
                                errs = append(errs, fmt.Sprintf("%s: %v", url, err))
                                continue
@@ -174,36 +166,51 @@ func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error)
                                errs = append(errs, fmt.Sprintf("%s: %v", url, err))
                                retryList = append(retryList, host)
                        } else if resp.StatusCode != http.StatusOK {
-                               respbody, _ := ioutil.ReadAll(&io.LimitedReader{resp.Body, 4096})
-                               resp.Body.Close()
+                               var respbody []byte
+                               if resp.Body != nil {
+                                       respbody, _ = ioutil.ReadAll(&io.LimitedReader{resp.Body, 4096})
+                                       resp.Body.Close()
+                               }
                                errs = append(errs, fmt.Sprintf("%s: %d %s",
                                        url, resp.StatusCode, bytes.TrimSpace(respbody)))
 
-                               if resp.StatusCode >= 500 {
-                                       // Server side failure, may be
-                                       // transient, can try again.
+                               if resp.StatusCode == 408 ||
+                                       resp.StatusCode == 429 ||
+                                       resp.StatusCode >= 500 {
+                                       // Timeout, too many requests, or other
+                                       // server side failure, transient
+                                       // error, can try again.
                                        retryList = append(retryList, host)
                                }
                        } else {
                                // Success.
-                               return HashCheckingReader{
-                                       Reader: resp.Body,
-                                       Hash:   md5.New(),
-                                       Check:  locator[0:32],
-                               }, resp.ContentLength, url, nil
+                               if method == "GET" {
+                                       return HashCheckingReader{
+                                               Reader: resp.Body,
+                                               Hash:   md5.New(),
+                                               Check:  locator[0:32],
+                                       }, resp.ContentLength, url, nil
+                               } else {
+                                       return nil, resp.ContentLength, url, nil
+                               }
                        }
                }
                serversToTry = retryList
        }
        log.Printf("DEBUG: GET %s failed: %v", locator, errs)
 
-       if len(retryList) > 0 {
-               // There was at least one failure to get a final answer
-               return nil, 0, "", KeepServerError
-       } else {
-               // Ever server returned a 4xx error
-               return nil, 0, "", BlockNotFound
-       }
+       return nil, 0, "", BlockNotFound
+}
+
+// Get() retrieves a block, given a locator. Returns a reader, the
+// expected data length, the URL the block is being fetched from, and
+// an error.
+//
+// If the block checksum does not match, the final Read() on the
+// reader returned by this method will return a BadChecksum error
+// instead of EOF.
+func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error) {
+       return kc.getOrHead("GET", locator)
 }
 
 // Ask() verifies that a block with the given hash is available and
@@ -214,18 +221,8 @@ func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error)
 // Returns the data size (content length) reported by the Keep service
 // and the URI reporting the data size.
 func (kc *KeepClient) Ask(locator string) (int64, string, error) {
-       for _, host := range kc.getSortedRoots(locator) {
-               url := host + "/" + locator
-               req, err := http.NewRequest("HEAD", url, nil)
-               if err != nil {
-                       continue
-               }
-               req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", kc.Arvados.ApiToken))
-               if resp, err := kc.Client.Do(req); err == nil && resp.StatusCode == http.StatusOK {
-                       return resp.ContentLength, url, nil
-               }
-       }
-       return 0, "", BlockNotFound
+       _, size, url, err := kc.getOrHead("HEAD", locator)
+       return size, url, err
 }
 
 // GetIndex retrieves a list of blocks stored on the given server whose hashes

diff --git a/sdk/go/keepclient/keepclient_test.go b/sdk/go/keepclient/keepclient_test.go
index 95269bfef6e9b5382d29c0913ef79f61d30a5bfd..b1395eff2070e226fc20ad0987979fd9f0bf14eb 100644 (file)
--- a/sdk/go/keepclient/keepclient_test.go
+++ b/sdk/go/keepclient/keepclient_test.go
@@ -554,7 +554,7 @@ func (s *StandaloneSuite) TestGetFail(c *C) {
        kc.SetServiceRoots(map[string]string{"x": ks.url}, map[string]string{ks.url: ""}, nil)
 
        r, n, url2, err := kc.Get(hash)
-       c.Check(err, Equals, KeepServerError)
+       c.Check(err, Equals, BlockNotFound)
        c.Check(n, Equals, int64(0))
        c.Check(url2, Equals, "")
        c.Check(r, Equals, nil)
@@ -599,7 +599,7 @@ func (s *StandaloneSuite) TestGetNetError(c *C) {
        kc.SetServiceRoots(map[string]string{"x": "http://localhost:62222"}, map[string]string{"http://localhost:62222": ""}, nil)
 
        r, n, url2, err := kc.Get(hash)
-       c.Check(err, Equals, KeepServerError)
+       c.Check(err, Equals, BlockNotFound)
        c.Check(n, Equals, int64(0))
        c.Check(url2, Equals, "")
        c.Check(r, Equals, nil)