var MissingArvadosApiToken = errors.New("Missing required environment variable ARVADOS_API_TOKEN")
var ErrInvalidArgument = errors.New("Invalid argument")
-// Before a POST or DELERE request, close any connections that were idle for this long
+// A common failure mode is to reuse a keepalive connection that has been
+// terminated (in a way that we can't detect) for being idle too long.
+// POST and DELETE are not safe to retry automatically, so we minimize
+// 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".
// Information about how to contact the Arvados server
type ArvadosClient struct {
+ // https
+ Scheme string
+
// Arvados API server, form "host:port"
ApiServer string
// 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
lastClosedIdlesAt time.Time
+
+ // Number of retries
+ 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"))
external := matchTrue.MatchString(os.Getenv("ARVADOS_EXTERNAL_CLIENT"))
ac = ArvadosClient{
+ Scheme: "https",
ApiServer: os.Getenv("ARVADOS_API_HOST"),
ApiToken: os.Getenv("ARVADOS_API_TOKEN"),
ApiInsecure: insecure,
Client: &http.Client{Transport: &http.Transport{
TLSClientConfig: &tls.Config{InsecureSkipVerify: insecure}}},
- External: external}
+ External: external,
+ Retries: 2}
+
+ for _, s := range strings.Split(os.Getenv("ARVADOS_KEEP_SERVICES"), " ") {
+ if s == "" {
+ continue
+ }
+ if u, err := url.Parse(s); err != nil {
+ return ac, fmt.Errorf("ARVADOS_KEEP_SERVICES: %q: %s", s, err)
+ } else if !u.IsAbs() {
+ return ac, fmt.Errorf("ARVADOS_KEEP_SERVICES: %q: not an absolute URI", s)
+ }
+ ac.KeepServiceURIs = append(ac.KeepServiceURIs, s)
+ }
if ac.ApiServer == "" {
return ac, MissingArvadosApiHost
// CallRaw is the same as Call() but returns a Reader that reads the
// response body, instead of taking an output object.
func (c ArvadosClient) CallRaw(method string, resourceType string, uuid string, action string, parameters Dict) (reader io.ReadCloser, err error) {
- var req *http.Request
-
+ scheme := c.Scheme
+ if scheme == "" {
+ scheme = "https"
+ }
u := url.URL{
- Scheme: "https",
+ Scheme: scheme,
Host: c.ApiServer}
if resourceType != API_DISCOVERY_RESOURCE {
}
}
- if method == "GET" || method == "HEAD" {
- u.RawQuery = vals.Encode()
- if req, err = http.NewRequest(method, u.String(), nil); err != nil {
- return nil, err
- }
- } else {
- if req, err = http.NewRequest(method, u.String(), bytes.NewBufferString(vals.Encode())); err != nil {
- return nil, err
- }
- req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
- }
-
- // Add api token header
- req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", c.ApiToken))
- if c.External {
- req.Header.Add("X-External-Client", "1")
+ retryable := false
+ switch method {
+ case "GET", "HEAD", "PUT", "OPTIONS", "DELETE":
+ retryable = true
}
- // Before a POST or DELETE, close any idle connections
- if method == "POST" || method == "DELETE" {
+ // 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
+ var req *http.Request
var resp *http.Response
- if resp, err = c.Client.Do(req); err != nil {
- return nil, err
- }
- if resp.StatusCode == http.StatusOK {
- return resp.Body, nil
+ 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 {
+ return nil, err
+ }
+ } else {
+ if req, err = http.NewRequest(method, u.String(), bytes.NewBufferString(vals.Encode())); err != nil {
+ return nil, err
+ }
+ req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
+ }
+
+ // Add api token header
+ req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", c.ApiToken))
+ if c.External {
+ req.Header.Add("X-External-Client", "1")
+ }
+
+ resp, err = c.Client.Do(req)
+ if err != nil {
+ if retryable {
+ time.Sleep(RetryDelay)
+ continue
+ } else {
+ return nil, err
+ }
+ }
+
+ if resp.StatusCode == http.StatusOK {
+ return resp.Body, nil
+ }
+
+ defer resp.Body.Close()
+
+ switch resp.StatusCode {
+ case 408, 409, 422, 423, 500, 502, 503, 504:
+ time.Sleep(RetryDelay)
+ continue
+ default:
+ return nil, newAPIServerError(c.ApiServer, resp)
+ }
}
- defer resp.Body.Close()
- return nil, newAPIServerError(c.ApiServer, resp)
+ if resp != nil {
+ return nil, newAPIServerError(c.ApiServer, resp)
+ }
+ return nil, err
}
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()