5824: Merge branch 'master' into 5824-keep-web

[arvados.git] / sdk / go / keepclient / keepclient.go

diff --git a/sdk/go/keepclient/keepclient.go b/sdk/go/keepclient/keepclient.go
index e74ae2cf08da0401bab6b808cf7333af05ef8a36..0e6fadcc3548c99d2e85c30219a74ffdce42bf72 100644 (file)
--- a/sdk/go/keepclient/keepclient.go
+++ b/sdk/go/keepclient/keepclient.go
@@ -22,7 +22,33 @@ import (
 // A Keep "block" is 64MB.
 const BLOCKSIZE = 64 * 1024 * 1024
 
-var BlockNotFound = errors.New("Block not found")
+// Error interface with an error and boolean indicating whether the error is temporary
+type Error interface {
+       error
+       Temporary() bool
+}
+
+// multipleResponseError is of type Error
+type multipleResponseError struct {
+       error
+       isTemp bool
+}
+
+func (e *multipleResponseError) Temporary() bool {
+       return e.isTemp
+}
+
+// BlockNotFound is a multipleResponseError where isTemp is false
+var BlockNotFound = &ErrNotFound{multipleResponseError{
+       error:  errors.New("Block not found"),
+       isTemp: false,
+}}
+
+// ErrNotFound is a multipleResponseError where isTemp can be true or false
+type ErrNotFound struct {
+       multipleResponseError
+}
+
 var InsufficientReplicasError = errors.New("Could not write sufficient replicas")
 var OversizeBlockError = errors.New("Exceeded maximum block size (" + strconv.Itoa(BLOCKSIZE) + ")")
 var MissingArvadosApiHost = errors.New("Missing required environment variable ARVADOS_API_HOST")
@@ -145,7 +171,12 @@ func (kc *KeepClient) getOrHead(method string, locator string) (io.ReadCloser, i
        var errs []string
 
        tries_remaining := 1 + kc.Retries
+
        serversToTry := kc.getSortedRoots(locator)
+
+       numServers := len(serversToTry)
+       count404 := 0
+
        var retryList []string
 
        for tries_remaining > 0 {
@@ -181,6 +212,8 @@ func (kc *KeepClient) getOrHead(method string, locator string) (io.ReadCloser, i
                                        // server side failure, transient
                                        // error, can try again.
                                        retryList = append(retryList, host)
+                               } else if resp.StatusCode == 404 {
+                                       count404++
                                }
                        } else {
                                // Success.
@@ -201,7 +234,16 @@ func (kc *KeepClient) getOrHead(method string, locator string) (io.ReadCloser, i
        }
        log.Printf("DEBUG: %s %s failed: %v", method, locator, errs)
 
-       return nil, 0, "", BlockNotFound
+       var err error
+       if count404 == numServers {
+               err = BlockNotFound
+       } else {
+               err = &ErrNotFound{multipleResponseError{
+                       error:  fmt.Errorf("%s %s failed: %v", method, locator, errs),
+                       isTemp: len(serversToTry) > 0,
+               }}
+       }
+       return nil, 0, "", err
 }
 
 // Get() retrieves a block, given a locator. Returns a reader, the