/* Simple Arvados Go SDK for communicating with API server. */ package arvadosclient import ( "bytes" "crypto/tls" "encoding/json" "errors" "fmt" "io" "net/http" "net/url" "os" "regexp" "strings" "time" ) type StringMatcher func(string) bool var UUIDMatch StringMatcher = regexp.MustCompile(`^[a-z0-9]{5}-[a-z0-9]{5}-[a-z0-9]{15}$`).MatchString var PDHMatch StringMatcher = regexp.MustCompile(`^[0-9a-f]{32}\+\d+$`).MatchString var MissingArvadosApiHost = errors.New("Missing required environment variable ARVADOS_API_HOST") var MissingArvadosApiToken = errors.New("Missing required environment variable ARVADOS_API_TOKEN") var ErrInvalidArgument = errors.New("Invalid argument") // 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". ServerAddress string // Components of server response. HttpStatusCode int HttpStatusMessage string // Additional error details from response body. ErrorDetails []string } func (e APIServerError) Error() string { if len(e.ErrorDetails) > 0 { return fmt.Sprintf("arvados API server error: %s (%d: %s) returned by %s", strings.Join(e.ErrorDetails, "; "), e.HttpStatusCode, e.HttpStatusMessage, e.ServerAddress) } else { return fmt.Sprintf("arvados API server error: %d: %s returned by %s", e.HttpStatusCode, e.HttpStatusMessage, e.ServerAddress) } } // Helper type so we don't have to write out 'map[string]interface{}' every time. type Dict map[string]interface{} // Information about how to contact the Arvados server type ArvadosClient struct { // https Scheme string // Arvados API server, form "host:port" ApiServer string // Arvados API token for authentication ApiToken string // Whether to require a valid SSL certificate or not ApiInsecure bool // Client object shared by client requests. Supports HTTP KeepAlive. Client *http.Client // If true, sets the X-External-Client header to indicate // the client is outside the cluster. External bool // 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. 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, Retries: 2} if ac.ApiServer == "" { return ac, MissingArvadosApiHost } if ac.ApiToken == "" { return ac, MissingArvadosApiToken } ac.lastClosedIdlesAt = time.Now() return ac, err } // 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) { scheme := c.Scheme if scheme == "" { scheme = "https" } u := url.URL{ Scheme: scheme, Host: c.ApiServer} if resourceType != API_DISCOVERY_RESOURCE { u.Path = "/arvados/v1" } if resourceType != "" { u.Path = u.Path + "/" + resourceType } if uuid != "" { u.Path = u.Path + "/" + uuid } if action != "" { u.Path = u.Path + "/" + action } if parameters == nil { parameters = make(Dict) } vals := make(url.Values) for k, v := range parameters { if s, ok := v.(string); ok { vals.Set(k, s) } else if m, err := json.Marshal(v); err == nil { vals.Set(k, string(m)) } } retryable := false switch method { case "GET", "HEAD", "PUT", "OPTIONS", "POST", "DELETE": retryable = true } // 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() } } // Make the request var req *http.Request var resp *http.Response 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) } } if resp != nil { return nil, newAPIServerError(c.ApiServer, resp) } else { return nil, err } } func newAPIServerError(ServerAddress string, resp *http.Response) APIServerError { ase := APIServerError{ ServerAddress: ServerAddress, HttpStatusCode: resp.StatusCode, HttpStatusMessage: resp.Status} // If the response body has {"errors":["reason1","reason2"]} // then return those reasons. var errInfo = Dict{} if err := json.NewDecoder(resp.Body).Decode(&errInfo); err == nil { if errorList, ok := errInfo["errors"]; ok { if errArray, ok := errorList.([]interface{}); ok { for _, errItem := range errArray { // We expect an array of strings here. // Non-strings will be passed along // JSON-encoded. if s, ok := errItem.(string); ok { ase.ErrorDetails = append(ase.ErrorDetails, s) } else if j, err := json.Marshal(errItem); err == nil { ase.ErrorDetails = append(ase.ErrorDetails, string(j)) } } } } } return ase } // Call an API endpoint and parse the JSON response into an object. // // method - HTTP method: GET, HEAD, PUT, POST, PATCH or DELETE. // resourceType - the type of arvados resource to act on (e.g., "collections", "pipeline_instances"). // uuid - the uuid of the specific item to access. May be empty. // action - API method name (e.g., "lock"). This is often empty if implied by method and uuid. // parameters - method parameters. // output - a map or annotated struct which is a legal target for encoding/json/Decoder. // // 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 { reader, err := c.CallRaw(method, resourceType, uuid, action, parameters) if reader != nil { defer reader.Close() } if err != nil { return err } if output != nil { dec := json.NewDecoder(reader) if err = dec.Decode(output); err != nil { return err } } return nil } // Create a new resource. See Call for argument descriptions. func (c ArvadosClient) Create(resourceType string, parameters Dict, output interface{}) error { return c.Call("POST", resourceType, "", "", parameters, output) } // Delete a resource. See Call for argument descriptions. func (c ArvadosClient) Delete(resource string, uuid string, parameters Dict, output interface{}) (err error) { return c.Call("DELETE", resource, uuid, "", parameters, output) } // Modify attributes of a resource. See Call for argument descriptions. func (c ArvadosClient) Update(resourceType string, uuid string, parameters Dict, output interface{}) (err error) { return c.Call("PUT", resourceType, uuid, "", parameters, output) } // Get a resource. See Call for argument descriptions. func (c ArvadosClient) Get(resourceType string, uuid string, parameters Dict, output interface{}) (err error) { if !UUIDMatch(uuid) && !(resourceType == "collections" && PDHMatch(uuid)) { // No object has uuid == "": there is no need to make // an API call. Furthermore, the HTTP request for such // an API call would be "GET /arvados/v1/type/", which // is liable to be misinterpreted as the List API. return ErrInvalidArgument } return c.Call("GET", resourceType, uuid, "", parameters, output) } // List resources of a given type. See Call for argument descriptions. func (c ArvadosClient) List(resource string, parameters Dict, output interface{}) (err error) { return c.Call("GET", resource, "", "", parameters, output) } const API_DISCOVERY_RESOURCE = "discovery/v1/apis/arvados/v1/rest" // Discovery returns the value of the given parameter in the discovery // document. Returns a non-nil error if the discovery document cannot // be retrieved/decoded. Returns ErrInvalidArgument if the requested // parameter is not found in the discovery document. func (c *ArvadosClient) Discovery(parameter string) (value interface{}, err error) { if len(c.DiscoveryDoc) == 0 { c.DiscoveryDoc = make(Dict) err = c.Call("GET", API_DISCOVERY_RESOURCE, "", "", nil, &c.DiscoveryDoc) if err != nil { return nil, err } } var found bool value, found = c.DiscoveryDoc[parameter] if found { return value, nil } else { return value, ErrInvalidArgument } }