server

Documentation

Overview

Package server configures and launches http/rpc server and storage engines specific to the type of DVID platform: local (e.g., running on MacBook Pro), clustered, or using cloud-based services like Google Cloud.

Datatypes can use any of the three tiers of storage (MetaData, Mutable, Immutable) that provide a layer of storage semantics (latency, mutability, etc) on top of underlying storage engines.

The DVID web client is also managed from this package. For a DVID web console, see the repo:

https://github.com/janelia-flyem/dvid-console

The goal of a DVID web console is to provide a GUI for monitoring and performing a subset of operations in a nicely formatted view.

DVID command line interaction occurs via the rpc interface to a running server. Please see the main DVID documentation:

http://godoc.org/github.com/janelia-flyem/dvid

Index

• Constants
• Variables
• func About() string
• func AboutJSON() (jsonStr string, err error)
• func BadAPIRequest(w http.ResponseWriter, r *http.Request, d dvid.Data)
• func BadRequest(w http.ResponseWriter, r *http.Request, format interface{}, ...)
• func BlockOnInteractiveRequests(caller ...string)
• func CreateTestInstance(t *testing.T, uuid dvid.UUID, typename, name string, config dvid.Config)
• func CreateTestReplaceSync(t *testing.T, uuid dvid.UUID, name string, syncs ...string)
• func CreateTestSync(t *testing.T, uuid dvid.UUID, name string, syncs ...string)
• func DecodeJSON(r *http.Request) (dvid.Config, error)
• func GitVersion() string
• func GotInteractiveRequest()
• func LoadConfig(filename string) (*datastore.InstanceConfig, *dvid.LogConfig, *storage.Backend, error)
• func NotFound(w http.ResponseWriter, r *http.Request)
• func SendNotification(message string, recipients []string) error
• func SendRPC(addr string, req datastore.Request) error
• func Serve()
• func ServeSingleHTTP(w http.ResponseWriter, r *http.Request)
• func SetMaxThrottleOps(maxOps int)
• func SetReadOnly(on bool)
• func Shutdown()
• func TestBadHTTP(t *testing.T, method, urlStr string, payload io.Reader)
• func TestHTTP(t *testing.T, method, urlStr string, payload io.Reader) []byte
• func TestHTTPResponse(t *testing.T, method, urlStr string, payload io.Reader) *httptest.ResponseRecorder
• func ThrottledHTTP(w http.ResponseWriter) bool
• func ThrottledOpDone()
• type Config
  • func GetConfig() Config
• type WebMux

Constants

const (
	// DefaultWebAddress is the default URL of the DVID web server
	DefaultWebAddress = "localhost:8000"

	// DefaultRPCAddress is the default RPC address for command-line use of a remote DVID server
	DefaultRPCAddress = "localhost:8001"

	// ErrorLogFilename is the name of the server error log, stored in the datastore directory.
	ErrorLogFilename = "dvid-errors.log"
)

const (
	// WebAPIVersion is the string version of the API.  Once DVID is somewhat stable,
	// this will be "v1/", "v2/", etc.
	WebAPIVersion = ""

	// The relative URL path to our Level 2 REST API
	WebAPIPath = "/api/" + WebAPIVersion

	// WriteTimeout is the maximum time in seconds DVID will wait to write data down HTTP connection.
	WriteTimeout = 300 * time.Second

	// ReadTimeout is the maximum time in seconds DVID will wait to read data from HTTP connection.
	ReadTimeout = 300 * time.Second
)

const RPCHelpMessage = `` /* 3389-byte string literal not displayed */

const WebHelp = `` /* 10704-byte string literal not displayed */

Variables

var (
	// Don't allow requests that will return more than this amount of data.
	MaxDataRequest = int64(3) * dvid.Giga

	// InteractiveOpsPer2Min gives the number of interactive-level requests
	// received over the last 2 minutes.  This is useful for throttling "batch"
	// operations on a single DVID server.  Note that this metric is an lower
	// bound on the number of interactive requests over the last minute since
	// we do non-blocking reports.
	InteractiveOpsPer2Min int

	// MaxInteractiveOpsBeforeBlock specifies the number of interactive requests
	// per minute that are allowed before batch-like computation (e.g., loading
	// of voxel volumes) is blocked.
	MaxInteractiveOpsBeforeBlock int = 3

	// ActiveHandlers is maximum number of active handlers over last second.
	ActiveHandlers int

	// MaxChunkHandlers sets the maximum number of chunk handlers (goroutines) that
	// can be multiplexed onto available cores.  (See -numcpu setting in dvid.go)
	MaxChunkHandlers = runtime.NumCPU()

	// HandlerToken is buffered channel to limit spawning of goroutines.
	// See ProcessChunk() in datatype/imageblk for example.
	HandlerToken = make(chan int, MaxChunkHandlers)

	// SpawnGoroutineMutex is a global lock for compute-intense processes that want to
	// spawn goroutines that consume handler tokens.  This lets processes capture most
	// if not all available handler tokens in a FIFO basis rather than have multiple
	// concurrent requests launch a few goroutines each.
	SpawnGoroutineMutex sync.Mutex

	// Timeout in seconds for waiting to open a datastore for exclusive access.
	TimeoutSecs int
)

var (
	// DefaultHost is the default most understandable alias for this server.
	DefaultHost = "localhost"
)

Functions

func About

func About() string

About returns a chart of version identifiers for the DVID source code, DVID datastore, and all component data types for this executable.

func AboutJSON

func AboutJSON() (jsonStr string, err error)

AboutJSON returns a JSON string describing the properties of this server.

func BadAPIRequest

func BadAPIRequest(w http.ResponseWriter, r *http.Request, d dvid.Data)

BadAPIRequest writes a standard error message to http.ResponseWriter for a badly formatted API call.

func BadRequest

func BadRequest(w http.ResponseWriter, r *http.Request, format interface{}, args ...interface{})

BadRequest writes an error message out to the http.ResponseWriter using format similar to fmt.Printf.

func BlockOnInteractiveRequests

func BlockOnInteractiveRequests(caller ...string)

BlockOnInteractiveRequests will block this goroutine until the number of interactive requests dips below MaxInteractiveOpsBeforeBlock.

func CreateTestInstance

func CreateTestInstance(t *testing.T, uuid dvid.UUID, typename, name string, config dvid.Config)

func CreateTestReplaceSync

func CreateTestReplaceSync(t *testing.T, uuid dvid.UUID, name string, syncs ...string)

func CreateTestSync

func CreateTestSync(t *testing.T, uuid dvid.UUID, name string, syncs ...string)

func DecodeJSON

func DecodeJSON(r *http.Request) (dvid.Config, error)

DecodeJSON decodes JSON passed in a request into a dvid.Config.

func GitVersion

func GitVersion() string

GitVersion returns a git-derived string that allows recovery of the exact source code used for this DVID server.

func GotInteractiveRequest

func GotInteractiveRequest()

GotInteractiveRequest can be called to track the # of interactive requests that require some amount of computation. Don't use this to track simple polling APIs. This routine will not block.

func LoadConfig

func LoadConfig(filename string) (*datastore.InstanceConfig, *dvid.LogConfig, *storage.Backend, error)

LoadConfig loads DVID server configuration from a TOML file.

func NotFound

func NotFound(w http.ResponseWriter, r *http.Request)

func SendNotification

func SendNotification(message string, recipients []string) error

SendNotification sends e-mail to the given recipients or the default emails loaded during configuration.

func SendRPC

func SendRPC(addr string, req datastore.Request) error

SendRPC sends a request to a remote DVID.

func Serve

func Serve()

Serve starts HTTP and RPC servers.

func ServeSingleHTTP

func ServeSingleHTTP(w http.ResponseWriter, r *http.Request)

ServeSingleHTTP fulfills one request using the default web Mux.

func SetMaxThrottleOps

func SetMaxThrottleOps(maxOps int)

func SetReadOnly

func SetReadOnly(on bool)

func Shutdown

func Shutdown()

Shutdown handles graceful cleanup of server functions before exiting DVID. This may not be so graceful if the chunk handler uses cgo since the interrupt may be caught during cgo execution.

func TestBadHTTP

func TestBadHTTP(t *testing.T, method, urlStr string, payload io.Reader)

TestBadHTTP expects a HTTP response with an error status code.

func TestHTTP

func TestHTTP(t *testing.T, method, urlStr string, payload io.Reader) []byte

TestHTTP returns the response body bytes for a test request, making sure any response has status OK.

func TestHTTPResponse

func TestHTTPResponse(t *testing.T, method, urlStr string, payload io.Reader) *httptest.ResponseRecorder

TestHTTPResponse returns a response from a test run of the DVID server. Use TestHTTP if you just want the response body bytes.

func ThrottledHTTP

func ThrottledHTTP(w http.ResponseWriter) bool

ThrottledHTTP checks if a request can continue under throttling. If so, it returns false. If it cannot (throttled state), it sends a http.StatusServiceUnavailable and returns true. Throttling is controlled by

func ThrottledOpDone

func ThrottledOpDone()

ThrottleOpDone marks the end of a throttled operation, allowing another op blocked by ThrottledHTTP() to succeed.

Types

type Config

type Config interface {
	Host() string // User understandable alias for this server, e.g., "emdata2" instead of "localhost" or "c06u30".
	HTTPAddress() string
	RPCAddress() string

	// Path to web client files
	WebClient() string

	// Set timing in HTTP header
	AllowTiming() bool
}

DVID server configuration parameters. Should be set by platform-specific implementations.

func GetConfig

func GetConfig() Config

Returns configuration settings for the server, which is set by each platform-specific server code.

type WebMux

type WebMux struct {
	*web.Mux
	sync.Mutex
	// contains filtered or unexported fields
}