9550: Update comments.

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

diff --git a/sdk/go/arvadosclient/arvadosclient.go b/sdk/go/arvadosclient/arvadosclient.go
index a5d5a022196b69359a1622a4fe17f7a4078dd552..57f81c2c86479aef0abab228467915ae9170ecdd 100644 (file)
--- a/sdk/go/arvadosclient/arvadosclient.go
+++ b/sdk/go/arvadosclient/arvadosclient.go
@@ -32,6 +32,8 @@ var ErrInvalidArgument = errors.New("Invalid argument")
 // such failures by always using a new or recently active socket.
 var MaxIdleConnectionDuration = 30 * time.Second
 
+var RetryDelay = 2 * time.Second
+
 // Indicates an error that was returned by the API server.
 type APIServerError struct {
        // Address of server returning error, of the form "host:port".
@@ -84,6 +86,12 @@ type ArvadosClient struct {
        // the client is outside the cluster.
        External bool
 
+       // Base URIs of Keep services, e.g., {"https://host1:8443",
+       // "https://host2:8443"}.  If this is nil, Keep clients will
+       // use the arvados.v1.keep_services.accessible API to discover
+       // available services.
+       KeepServiceURIs []string
+
        // Discovery document
        DiscoveryDoc Dict
 
@@ -93,9 +101,10 @@ type ArvadosClient struct {
        Retries int
 }
 
-// Create a new ArvadosClient, initialized with standard Arvados environment
-// variables ARVADOS_API_HOST, ARVADOS_API_TOKEN, and (optionally)
-// ARVADOS_API_HOST_INSECURE.
+// MakeArvadosClient creates a new ArvadosClient using the standard
+// environment variables ARVADOS_API_HOST, ARVADOS_API_TOKEN,
+// ARVADOS_API_HOST_INSECURE, ARVADOS_EXTERNAL_CLIENT, and
+// ARVADOS_KEEP_SERVICES.
 func MakeArvadosClient() (ac ArvadosClient, err error) {
        var matchTrue = regexp.MustCompile("^(?i:1|yes|true)$")
        insecure := matchTrue.MatchString(os.Getenv("ARVADOS_API_HOST_INSECURE"))
@@ -111,6 +120,10 @@ func MakeArvadosClient() (ac ArvadosClient, err error) {
                External: external,
                Retries:  2}
 
+       if s := os.Getenv("ARVADOS_KEEP_SERVICES"); s != "" {
+               ac.KeepServiceURIs = strings.Split(s, " ")
+       }
+
        if ac.ApiServer == "" {
                return ac, MissingArvadosApiHost
        }
@@ -161,14 +174,26 @@ func (c ArvadosClient) CallRaw(method string, resourceType string, uuid string,
                }
        }
 
+       retryable := false
+       switch method {
+       case "GET", "HEAD", "PUT", "OPTIONS", "DELETE":
+               retryable = true
+       }
+
+       // Non-retryable methods such as POST are not safe to retry automatically,
+       // so we minimize such failures by always using a new or recently active socket
+       if !retryable {
+               if time.Since(c.lastClosedIdlesAt) > MaxIdleConnectionDuration {
+                       c.lastClosedIdlesAt = time.Now()
+                       c.Client.Transport.(*http.Transport).CloseIdleConnections()
+               }
+       }
+
        // Make the request
-       remainingTries := 1 + c.Retries
        var req *http.Request
        var resp *http.Response
-       var errs []string
-       var badResp bool
 
-       for remainingTries > 0 {
+       for attempt := 0; attempt <= c.Retries; attempt++ {
                if method == "GET" || method == "HEAD" {
                        u.RawQuery = vals.Encode()
                        if req, err = http.NewRequest(method, u.String(), nil); err != nil {
@@ -187,21 +212,10 @@ func (c ArvadosClient) CallRaw(method string, resourceType string, uuid string,
                        req.Header.Add("X-External-Client", "1")
                }
 
-               // POST and DELETE are not safe to retry automatically, so we minimize
-               // such failures by always using a new or recently active socket
-               if method == "POST" || method == "DELETE" {
-                       if time.Since(c.lastClosedIdlesAt) > MaxIdleConnectionDuration {
-                               c.lastClosedIdlesAt = time.Now()
-                               c.Client.Transport.(*http.Transport).CloseIdleConnections()
-                       }
-               }
-
                resp, err = c.Client.Do(req)
                if err != nil {
-                       if method == "GET" || method == "HEAD" || method == "PUT" {
-                               errs = append(errs, err.Error())
-                               badResp = false
-                               remainingTries -= 1
+                       if retryable {
+                               time.Sleep(RetryDelay)
                                continue
                        } else {
                                return nil, err
@@ -214,27 +228,19 @@ func (c ArvadosClient) CallRaw(method string, resourceType string, uuid string,
 
                defer resp.Body.Close()
 
-               if resp.StatusCode == 408 ||
-                       resp.StatusCode == 409 ||
-                       resp.StatusCode == 422 ||
-                       resp.StatusCode == 423 ||
-                       resp.StatusCode == 500 ||
-                       resp.StatusCode == 502 ||
-                       resp.StatusCode == 503 ||
-                       resp.StatusCode == 504 {
-                       badResp = true
-                       remainingTries -= 1
+               switch resp.StatusCode {
+               case 408, 409, 422, 423, 500, 502, 503, 504:
+                       time.Sleep(RetryDelay)
                        continue
-               } else {
+               default:
                        return nil, newAPIServerError(c.ApiServer, resp)
                }
        }
 
-       if badResp {
+       if resp != nil {
                return nil, newAPIServerError(c.ApiServer, resp)
-       } else {
-               return nil, fmt.Errorf("%v", errs)
        }
+       return nil, err
 }
 
 func newAPIServerError(ServerAddress string, resp *http.Response) APIServerError {
@@ -278,7 +284,7 @@ func newAPIServerError(ServerAddress string, resp *http.Response) APIServerError
 // Returns a non-nil error if an error occurs making the API call, the
 // API responds with a non-successful HTTP status, or an error occurs
 // parsing the response body.
-func (c ArvadosClient) Call(method string, resourceType string, uuid string, action string, parameters Dict, output interface{}) error {
+func (c ArvadosClient) Call(method, resourceType, uuid, action string, parameters Dict, output interface{}) error {
        reader, err := c.CallRaw(method, resourceType, uuid, action, parameters)
        if reader != nil {
                defer reader.Close()