"use strict";
/*
* Copyright 2019 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Subchannel = exports.subchannelAddressToString = exports.subchannelAddressEqual = exports.isTcpSubchannelAddress = void 0;
const http2 = require("http2");
const tls_1 = require("tls");
const channel_1 = require("./channel");
const backoff_timeout_1 = require("./backoff-timeout");
const resolver_1 = require("./resolver");
const logging = require("./logging");
const constants_1 = require("./constants");
const http_proxy_1 = require("./http_proxy");
const net = require("net");
const uri_parser_1 = require("./uri-parser");
const clientVersion = require('../../package.json').version;
const TRACER_NAME = 'subchannel';
function trace(text) {
logging.trace(constants_1.LogVerbosity.DEBUG, TRACER_NAME, text);
}
function refTrace(text) {
logging.trace(constants_1.LogVerbosity.DEBUG, 'subchannel_refcount', text);
}
const MIN_CONNECT_TIMEOUT_MS = 20000;
const INITIAL_BACKOFF_MS = 1000;
const BACKOFF_MULTIPLIER = 1.6;
const MAX_BACKOFF_MS = 120000;
const BACKOFF_JITTER = 0.2;
/* setInterval and setTimeout only accept signed 32 bit integers. JS doesn't
* have a constant for the max signed 32 bit integer, so this is a simple way
* to calculate it */
const KEEPALIVE_MAX_TIME_MS = ~(1 << 31);
const KEEPALIVE_TIMEOUT_MS = 20000;
const { HTTP2_HEADER_AUTHORITY, HTTP2_HEADER_CONTENT_TYPE, HTTP2_HEADER_METHOD, HTTP2_HEADER_PATH, HTTP2_HEADER_TE, HTTP2_HEADER_USER_AGENT, } = http2.constants;
/**
* Get a number uniformly at random in the range [min, max)
* @param min
* @param max
*/
function uniformRandom(min, max) {
return Math.random() * (max - min) + min;
}
const tooManyPingsData = Buffer.from('too_many_pings', 'ascii');
function isTcpSubchannelAddress(address) {
return 'port' in address;
}
exports.isTcpSubchannelAddress = isTcpSubchannelAddress;
function subchannelAddressEqual(address1, address2) {
if (isTcpSubchannelAddress(address1)) {
return (isTcpSubchannelAddress(address2) &&
address1.host === address2.host &&
address1.port === address2.port);
}
else {
return !isTcpSubchannelAddress(address2) && address1.path === address2.path;
}
}
exports.subchannelAddressEqual = subchannelAddressEqual;
function subchannelAddressToString(address) {
if (isTcpSubchannelAddress(address)) {
return address.host + ':' + address.port;
}
else {
return address.path;
}
}
exports.subchannelAddressToString = subchannelAddressToString;
class Subchannel {
/**
* A class representing a connection to a single backend.
* @param channelTarget The target string for the channel as a whole
* @param subchannelAddress The address for the backend that this subchannel
* will connect to
* @param options The channel options, plus any specific subchannel options
* for this subchannel
* @param credentials The channel credentials used to establish this
* connection
*/
constructor(channelTarget, subchannelAddress, options, credentials) {
this.channelTarget = channelTarget;
this.subchannelAddress = subchannelAddress;
this.options = options;
this.credentials = credentials;
/**
* The subchannel's current connectivity state. Invariant: `session` === `null`
* if and only if `connectivityState` is IDLE or TRANSIENT_FAILURE.
*/
this.connectivityState = channel_1.ConnectivityState.IDLE;
/**
* The underlying http2 session used to make requests.
*/
this.session = null;
/**
* Indicates that the subchannel should transition from TRANSIENT_FAILURE to
* CONNECTING instead of IDLE when the backoff timeout ends.
*/
this.continueConnecting = false;
/**
* A list of listener functions that will be called whenever the connectivity
* state changes. Will be modified by `addConnectivityStateListener` and
* `removeConnectivityStateListener`
*/
this.stateListeners = [];
/**
* A list of listener functions that will be called when the underlying
* socket disconnects. Used for ending active calls with an UNAVAILABLE
* status.
*/
this.disconnectListeners = [];
/**
* The amount of time in between sending pings
*/
this.keepaliveTimeMs = KEEPALIVE_MAX_TIME_MS;
/**
* The amount of time to wait for an acknowledgement after sending a ping
*/
this.keepaliveTimeoutMs = KEEPALIVE_TIMEOUT_MS;
/**
* Indicates whether keepalive pings should be sent without any active calls
*/
this.keepaliveWithoutCalls = false;
/**
* Tracks calls with references to this subchannel
*/
this.callRefcount = 0;
/**
* Tracks channels and subchannel pools with references to this subchannel
*/
this.refcount = 0;
// Build user-agent string.
this.userAgent = [
options['grpc.primary_user_agent'],
`grpc-node-js/${clientVersion}`,
options['grpc.secondary_user_agent'],
]
.filter((e) => e)
.join(' '); // remove falsey values first
if ('grpc.keepalive_time_ms' in options) {
this.keepaliveTimeMs = options['grpc.keepalive_time_ms'];
}
if ('grpc.keepalive_timeout_ms' in options) {
this.keepaliveTimeoutMs = options['grpc.keepalive_timeout_ms'];
}
if ('grpc.keepalive_permit_without_calls' in options) {
this.keepaliveWithoutCalls = options['grpc.keepalive_permit_without_calls'] === 1;
}
else {
this.keepaliveWithoutCalls = false;
}
this.keepaliveIntervalId = setTimeout(() => { }, 0);
clearTimeout(this.keepaliveIntervalId);
this.keepaliveTimeoutId = setTimeout(() => { }, 0);
clearTimeout(this.keepaliveTimeoutId);
const backoffOptions = {
initialDelay: options['grpc.initial_reconnect_backoff_ms'],
maxDelay: options['grpc.max_reconnect_backoff_ms'],
};
this.backoffTimeout = new backoff_timeout_1.BackoffTimeout(() => {
this.handleBackoffTimer();
}, backoffOptions);
this.subchannelAddressString = subchannelAddressToString(subchannelAddress);
}
handleBackoffTimer() {
if (this.continueConnecting) {
this.transitionToState([channel_1.ConnectivityState.TRANSIENT_FAILURE], channel_1.ConnectivityState.CONNECTING);
}
else {
this.transitionToState([channel_1.ConnectivityState.TRANSIENT_FAILURE], channel_1.ConnectivityState.IDLE);
}
}
/**
* Start a backoff timer with the current nextBackoff timeout
*/
startBackoff() {
this.backoffTimeout.runOnce();
}
stopBackoff() {
this.backoffTimeout.stop();
this.backoffTimeout.reset();
}
sendPing() {
var _a, _b;
logging.trace(constants_1.LogVerbosity.DEBUG, 'keepalive', 'Sending ping to ' + this.subchannelAddressString);
this.keepaliveTimeoutId = setTimeout(() => {
this.transitionToState([channel_1.ConnectivityState.READY], channel_1.ConnectivityState.IDLE);
}, this.keepaliveTimeoutMs);
(_b = (_a = this.keepaliveTimeoutId).unref) === null || _b === void 0 ? void 0 : _b.call(_a);
this.session.ping((err, duration, payload) => {
clearTimeout(this.keepaliveTimeoutId);
});
}
startKeepalivePings() {
var _a, _b;
this.keepaliveIntervalId = setInterval(() => {
this.sendPing();
}, this.keepaliveTimeMs);
(_b = (_a = this.keepaliveIntervalId).unref) === null || _b === void 0 ? void 0 : _b.call(_a);
/* Don't send a ping immediately because whatever caused us to start
* sending pings should also involve some network activity. */
}
stopKeepalivePings() {
clearInterval(this.keepaliveIntervalId);
clearTimeout(this.keepaliveTimeoutId);
}
createSession(proxyConnectionResult) {
var _a, _b, _c;
if (proxyConnectionResult.realTarget) {
trace(this.subchannelAddressString + ' creating HTTP/2 session through proxy to ' + proxyConnectionResult.realTarget);
}
else {
trace(this.subchannelAddressString + ' creating HTTP/2 session');
}
const targetAuthority = resolver_1.getDefaultAuthority((_a = proxyConnectionResult.realTarget) !== null && _a !== void 0 ? _a : this.channelTarget);
let connectionOptions = this.credentials._getConnectionOptions() || {};
connectionOptions.maxSendHeaderBlockLength = Number.MAX_SAFE_INTEGER;
if ('grpc-node.max_session_memory' in this.options) {
connectionOptions.maxSessionMemory = this.options['grpc-node.max_session_memory'];
}
let addressScheme = 'http://';
if ('secureContext' in connectionOptions) {
addressScheme = 'https://';
// If provided, the value of grpc.ssl_target_name_override should be used
// to override the target hostname when checking server identity.
// This option is used for testing only.
if (this.options['grpc.ssl_target_name_override']) {
const sslTargetNameOverride = this.options['grpc.ssl_target_name_override'];
connectionOptions.checkServerIdentity = (host, cert) => {
return tls_1.checkServerIdentity(sslTargetNameOverride, cert);
};
connectionOptions.servername = sslTargetNameOverride;
}
else {
const authorityHostname = (_c = (_b = uri_parser_1.splitHostPort(targetAuthority)) === null || _b === void 0 ? void 0 : _b.host) !== null && _c !== void 0 ? _c : 'localhost';
// We want to always set servername to support SNI
connectionOptions.servername = authorityHostname;
}
if (proxyConnectionResult.socket) {
/* This is part of the workaround for
* https://github.com/nodejs/node/issues/32922. Without that bug,
* proxyConnectionResult.socket would always be a plaintext socket and
* this would say
* connectionOptions.socket = proxyConnectionResult.socket; */
connectionOptions.createConnection = (authority, option) => {
return proxyConnectionResult.socket;
};
}
}
else {
/* In all but the most recent versions of Node, http2.connect does not use
* the options when establishing plaintext connections, so we need to
* establish that connection explicitly. */
connectionOptions.createConnection = (authority, option) => {
if (proxyConnectionResult.socket) {
return proxyConnectionResult.socket;
}
else {
/* net.NetConnectOpts is declared in a way that is more restrictive
* than what net.connect will actually accept, so we use the type
* assertion to work around that. */
return net.connect(this.subchannelAddress);
}
};
}
connectionOptions = Object.assign(Object.assign({}, connectionOptions), this.subchannelAddress);
/* http2.connect uses the options here:
* https://github.com/nodejs/node/blob/70c32a6d190e2b5d7b9ff9d5b6a459d14e8b7d59/lib/internal/http2/core.js#L3028-L3036
* The spread operator overides earlier values with later ones, so any port
* or host values in the options will be used rather than any values extracted
* from the first argument. In addition, the path overrides the host and port,
* as documented for plaintext connections here:
* https://nodejs.org/api/net.html#net_socket_connect_options_connectlistener
* and for TLS connections here:
* https://nodejs.org/api/tls.html#tls_tls_connect_options_callback. In
* earlier versions of Node, http2.connect passes these options to
* tls.connect but not net.connect, so in the insecure case we still need
* to set the createConnection option above to create the connection
* explicitly. We cannot do that in the TLS case because http2.connect
* passes necessary additional options to tls.connect.
* The first argument just needs to be parseable as a URL and the scheme
* determines whether the connection will be established over TLS or not.
*/
const session = http2.connect(addressScheme + targetAuthority, connectionOptions);
this.session = session;
session.unref();
/* For all of these events, check if the session at the time of the event
* is the same one currently attached to this subchannel, to ensure that
* old events from previous connection attempts cannot cause invalid state
* transitions. */
session.once('connect', () => {
if (this.session === session) {
this.transitionToState([channel_1.ConnectivityState.CONNECTING], channel_1.ConnectivityState.READY);
}
});
session.once('close', () => {
if (this.session === session) {
trace(this.subchannelAddressString + ' connection closed');
this.transitionToState([channel_1.ConnectivityState.CONNECTING], channel_1.ConnectivityState.TRANSIENT_FAILURE);
/* Transitioning directly to IDLE here should be OK because we are not
* doing any backoff, because a connection was established at some
* point */
this.transitionToState([channel_1.ConnectivityState.READY], channel_1.ConnectivityState.IDLE);
}
});
session.once('goaway', (errorCode, lastStreamID, opaqueData) => {
if (this.session === session) {
/* See the last paragraph of
* https://github.com/grpc/proposal/blob/master/A8-client-side-keepalive.md#basic-keepalive */
if (errorCode === http2.constants.NGHTTP2_ENHANCE_YOUR_CALM &&
opaqueData.equals(tooManyPingsData)) {
this.keepaliveTimeMs = Math.min(2 * this.keepaliveTimeMs, KEEPALIVE_MAX_TIME_MS);
logging.log(constants_1.LogVerbosity.ERROR, `Connection to ${uri_parser_1.uriToString(this.channelTarget)} at ${this.subchannelAddressString} rejected by server because of excess pings. Increasing ping interval to ${this.keepaliveTimeMs} ms`);
}
trace(this.subchannelAddressString +
' connection closed by GOAWAY with code ' +
errorCode);
this.transitionToState([channel_1.ConnectivityState.CONNECTING, channel_1.ConnectivityState.READY], channel_1.ConnectivityState.IDLE);
}
});
session.once('error', (error) => {
/* Do nothing here. Any error should also trigger a close event, which is
* where we want to handle that. */
trace(this.subchannelAddressString +
' connection closed with error ' +
error.message);
});
}
startConnectingInternal() {
var _a, _b;
/* Pass connection options through to the proxy so that it's able to
* upgrade it's connection to support tls if needed.
* This is a workaround for https://github.com/nodejs/node/issues/32922
* See https://github.com/grpc/grpc-node/pull/1369 for more info. */
const connectionOptions = this.credentials._getConnectionOptions() || {};
if ('secureContext' in connectionOptions) {
connectionOptions.ALPNProtocols = ['h2'];
// If provided, the value of grpc.ssl_target_name_override should be used
// to override the target hostname when checking server identity.
// This option is used for testing only.
if (this.options['grpc.ssl_target_name_override']) {
const sslTargetNameOverride = this.options['grpc.ssl_target_name_override'];
connectionOptions.checkServerIdentity = (host, cert) => {
return tls_1.checkServerIdentity(sslTargetNameOverride, cert);
};
connectionOptions.servername = sslTargetNameOverride;
}
else {
if ('grpc.http_connect_target' in this.options) {
/* This is more or less how servername will be set in createSession
* if a connection is successfully established through the proxy.
* If the proxy is not used, these connectionOptions are discarded
* anyway */
const targetPath = resolver_1.getDefaultAuthority((_a = uri_parser_1.parseUri(this.options['grpc.http_connect_target'])) !== null && _a !== void 0 ? _a : {
path: 'localhost',
});
const hostPort = uri_parser_1.splitHostPort(targetPath);
connectionOptions.servername = (_b = hostPort === null || hostPort === void 0 ? void 0 : hostPort.host) !== null && _b !== void 0 ? _b : targetPath;
}
}
}
http_proxy_1.getProxiedConnection(this.subchannelAddress, this.options, connectionOptions).then((result) => {
this.createSession(result);
}, (reason) => {
this.transitionToState([channel_1.ConnectivityState.CONNECTING], channel_1.ConnectivityState.TRANSIENT_FAILURE);
});
}
/**
* Initiate a state transition from any element of oldStates to the new
* state. If the current connectivityState is not in oldStates, do nothing.
* @param oldStates The set of states to transition from
* @param newState The state to transition to
* @returns True if the state changed, false otherwise
*/
transitionToState(oldStates, newState) {
if (oldStates.indexOf(this.connectivityState) === -1) {
return false;
}
trace(this.subchannelAddressString +
' ' +
channel_1.ConnectivityState[this.connectivityState] +
' -> ' +
channel_1.ConnectivityState[newState]);
const previousState = this.connectivityState;
this.connectivityState = newState;
switch (newState) {
case channel_1.ConnectivityState.READY:
this.stopBackoff();
this.session.socket.once('close', () => {
for (const listener of this.disconnectListeners) {
listener();
}
});
if (this.keepaliveWithoutCalls) {
this.startKeepalivePings();
}
break;
case channel_1.ConnectivityState.CONNECTING:
this.startBackoff();
this.startConnectingInternal();
this.continueConnecting = false;
break;
case channel_1.ConnectivityState.TRANSIENT_FAILURE:
if (this.session) {
this.session.close();
}
this.session = null;
this.stopKeepalivePings();
/* If the backoff timer has already ended by the time we get to the
* TRANSIENT_FAILURE state, we want to immediately transition out of
* TRANSIENT_FAILURE as though the backoff timer is ending right now */
if (!this.backoffTimeout.isRunning()) {
process.nextTick(() => {
this.handleBackoffTimer();
});
}
break;
case channel_1.ConnectivityState.IDLE:
if (this.session) {
this.session.close();
}
this.session = null;
this.stopKeepalivePings();
break;
default:
throw new Error(`Invalid state: unknown ConnectivityState ${newState}`);
}
/* We use a shallow copy of the stateListeners array in case a listener
* is removed during this iteration */
for (const listener of [...this.stateListeners]) {
listener(this, previousState, newState);
}
return true;
}
/**
* Check if the subchannel associated with zero calls and with zero channels.
* If so, shut it down.
*/
checkBothRefcounts() {
/* If no calls, channels, or subchannel pools have any more references to
* this subchannel, we can be sure it will never be used again. */
if (this.callRefcount === 0 && this.refcount === 0) {
this.transitionToState([
channel_1.ConnectivityState.CONNECTING,
channel_1.ConnectivityState.READY,
], channel_1.ConnectivityState.TRANSIENT_FAILURE);
}
}
callRef() {
refTrace(this.subchannelAddressString +
' callRefcount ' +
this.callRefcount +
' -> ' +
(this.callRefcount + 1));
if (this.callRefcount === 0) {
if (this.session) {
this.session.ref();
}
this.backoffTimeout.ref();
if (!this.keepaliveWithoutCalls) {
this.startKeepalivePings();
}
}
this.callRefcount += 1;
}
callUnref() {
refTrace(this.subchannelAddressString +
' callRefcount ' +
this.callRefcount +
' -> ' +
(this.callRefcount - 1));
this.callRefcount -= 1;
if (this.callRefcount === 0) {
if (this.session) {
this.session.unref();
}
this.backoffTimeout.unref();
if (!this.keepaliveWithoutCalls) {
this.stopKeepalivePings();
}
this.checkBothRefcounts();
}
}
ref() {
refTrace(this.subchannelAddressString +
' refcount ' +
this.refcount +
' -> ' +
(this.refcount + 1));
this.refcount += 1;
}
unref() {
refTrace(this.subchannelAddressString +
' refcount ' +
this.refcount +
' -> ' +
(this.refcount - 1));
this.refcount -= 1;
this.checkBothRefcounts();
}
unrefIfOneRef() {
if (this.refcount === 1) {
this.unref();
return true;
}
return false;
}
/**
* Start a stream on the current session with the given `metadata` as headers
* and then attach it to the `callStream`. Must only be called if the
* subchannel's current connectivity state is READY.
* @param metadata
* @param callStream
*/
startCallStream(metadata, callStream, extraFilterFactory) {
const headers = metadata.toHttp2Headers();
headers[HTTP2_HEADER_AUTHORITY] = callStream.getHost();
headers[HTTP2_HEADER_USER_AGENT] = this.userAgent;
headers[HTTP2_HEADER_CONTENT_TYPE] = 'application/grpc';
headers[HTTP2_HEADER_METHOD] = 'POST';
headers[HTTP2_HEADER_PATH] = callStream.getMethod();
headers[HTTP2_HEADER_TE] = 'trailers';
let http2Stream;
/* In theory, if an error is thrown by session.request because session has
* become unusable (e.g. because it has received a goaway), this subchannel
* should soon see the corresponding close or goaway event anyway and leave
* READY. But we have seen reports that this does not happen
* (https://github.com/googleapis/nodejs-firestore/issues/1023#issuecomment-653204096)
* so for defense in depth, we just discard the session when we see an
* error here.
*/
try {
http2Stream = this.session.request(headers);
}
catch (e) {
this.transitionToState([channel_1.ConnectivityState.READY], channel_1.ConnectivityState.TRANSIENT_FAILURE);
throw e;
}
let headersString = '';
for (const header of Object.keys(headers)) {
headersString += '\t\t' + header + ': ' + headers[header] + '\n';
}
logging.trace(constants_1.LogVerbosity.DEBUG, 'call_stream', 'Starting stream on subchannel ' + this.subchannelAddressString + ' with headers\n' + headersString);
callStream.attachHttp2Stream(http2Stream, this, extraFilterFactory);
}
/**
* If the subchannel is currently IDLE, start connecting and switch to the
* CONNECTING state. If the subchannel is current in TRANSIENT_FAILURE,
* the next time it would transition to IDLE, start connecting again instead.
* Otherwise, do nothing.
*/
startConnecting() {
/* First, try to transition from IDLE to connecting. If that doesn't happen
* because the state is not currently IDLE, check if it is
* TRANSIENT_FAILURE, and if so indicate that it should go back to
* connecting after the backoff timer ends. Otherwise do nothing */
if (!this.transitionToState([channel_1.ConnectivityState.IDLE], channel_1.ConnectivityState.CONNECTING)) {
if (this.connectivityState === channel_1.ConnectivityState.TRANSIENT_FAILURE) {
this.continueConnecting = true;
}
}
}
/**
* Get the subchannel's current connectivity state.
*/
getConnectivityState() {
return this.connectivityState;
}
/**
* Add a listener function to be called whenever the subchannel's
* connectivity state changes.
* @param listener
*/
addConnectivityStateListener(listener) {
this.stateListeners.push(listener);
}
/**
* Remove a listener previously added with `addConnectivityStateListener`
* @param listener A reference to a function previously passed to
* `addConnectivityStateListener`
*/
removeConnectivityStateListener(listener) {
const listenerIndex = this.stateListeners.indexOf(listener);
if (listenerIndex > -1) {
this.stateListeners.splice(listenerIndex, 1);
}
}
addDisconnectListener(listener) {
this.disconnectListeners.push(listener);
}
removeDisconnectListener(listener) {
const listenerIndex = this.disconnectListeners.indexOf(listener);
if (listenerIndex > -1) {
this.disconnectListeners.splice(listenerIndex, 1);
}
}
/**
* Reset the backoff timeout, and immediately start connecting if in backoff.
*/
resetBackoff() {
this.backoffTimeout.reset();
this.transitionToState([channel_1.ConnectivityState.TRANSIENT_FAILURE], channel_1.ConnectivityState.CONNECTING);
}
getAddress() {
return this.subchannelAddressString;
}
}
exports.Subchannel = Subchannel;
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