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diff --git a/frontend-old/node_modules/@grpc/grpc-js/src/load-balancer-pick-first.ts b/frontend-old/node_modules/@grpc/grpc-js/src/load-balancer-pick-first.ts
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@@ -0,0 +1,487 @@
+/*
+ * 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.
+ *
+ */
+
+import {
+  LoadBalancer,
+  ChannelControlHelper,
+  LoadBalancingConfig,
+  registerDefaultLoadBalancerType,
+  registerLoadBalancerType,
+} from './load-balancer';
+import { ConnectivityState } from './connectivity-state';
+import {
+  QueuePicker,
+  Picker,
+  PickArgs,
+  CompletePickResult,
+  PickResultType,
+  UnavailablePicker,
+} from './picker';
+import { SubchannelAddress } from './subchannel-address';
+import * as logging from './logging';
+import { LogVerbosity } from './constants';
+import {
+  SubchannelInterface,
+  ConnectivityStateListener,
+} from './subchannel-interface';
+
+const TRACER_NAME = 'pick_first';
+
+function trace(text: string): void {
+  logging.trace(LogVerbosity.DEBUG, TRACER_NAME, text);
+}
+
+const TYPE_NAME = 'pick_first';
+
+/**
+ * Delay after starting a connection on a subchannel before starting a
+ * connection on the next subchannel in the list, for Happy Eyeballs algorithm.
+ */
+const CONNECTION_DELAY_INTERVAL_MS = 250;
+
+export class PickFirstLoadBalancingConfig implements LoadBalancingConfig {
+  constructor(private readonly shuffleAddressList: boolean) {}
+
+  getLoadBalancerName(): string {
+    return TYPE_NAME;
+  }
+
+  toJsonObject(): object {
+    return {
+      [TYPE_NAME]: {
+        shuffleAddressList: this.shuffleAddressList,
+      },
+    };
+  }
+
+  getShuffleAddressList() {
+    return this.shuffleAddressList;
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  static createFromJson(obj: any) {
+    if (
+      'shuffleAddressList' in obj &&
+      !(typeof obj.shuffleAddressList === 'boolean')
+    ) {
+      throw new Error(
+        'pick_first config field shuffleAddressList must be a boolean if provided'
+      );
+    }
+    return new PickFirstLoadBalancingConfig(obj.shuffleAddressList === true);
+  }
+}
+
+/**
+ * Picker for a `PickFirstLoadBalancer` in the READY state. Always returns the
+ * picked subchannel.
+ */
+class PickFirstPicker implements Picker {
+  constructor(private subchannel: SubchannelInterface) {}
+
+  pick(pickArgs: PickArgs): CompletePickResult {
+    return {
+      pickResultType: PickResultType.COMPLETE,
+      subchannel: this.subchannel,
+      status: null,
+      onCallStarted: null,
+      onCallEnded: null,
+    };
+  }
+}
+
+interface SubchannelChild {
+  subchannel: SubchannelInterface;
+  hasReportedTransientFailure: boolean;
+}
+
+/**
+ * Return a new array with the elements of the input array in a random order
+ * @param list The input array
+ * @returns A shuffled array of the elements of list
+ */
+export function shuffled<T>(list: T[]): T[] {
+  const result = list.slice();
+  for (let i = result.length - 1; i > 1; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    const temp = result[i];
+    result[i] = result[j];
+    result[j] = temp;
+  }
+  return result;
+}
+
+export class PickFirstLoadBalancer implements LoadBalancer {
+  /**
+   * The list of subchannels this load balancer is currently attempting to
+   * connect to.
+   */
+  private children: SubchannelChild[] = [];
+  /**
+   * The current connectivity state of the load balancer.
+   */
+  private currentState: ConnectivityState = ConnectivityState.IDLE;
+  /**
+   * The index within the `subchannels` array of the subchannel with the most
+   * recently started connection attempt.
+   */
+  private currentSubchannelIndex = 0;
+  /**
+   * The currently picked subchannel used for making calls. Populated if
+   * and only if the load balancer's current state is READY. In that case,
+   * the subchannel's current state is also READY.
+   */
+  private currentPick: SubchannelInterface | null = null;
+  /**
+   * Listener callback attached to each subchannel in the `subchannels` list
+   * while establishing a connection.
+   */
+  private subchannelStateListener: ConnectivityStateListener = (
+    subchannel,
+    previousState,
+    newState,
+    keepaliveTime,
+    errorMessage
+  ) => {
+    this.onSubchannelStateUpdate(subchannel, previousState, newState, errorMessage);
+  };
+  /**
+   * Timer reference for the timer tracking when to start
+   */
+  private connectionDelayTimeout: NodeJS.Timeout;
+
+  private triedAllSubchannels = false;
+
+  /**
+   * The LB policy enters sticky TRANSIENT_FAILURE mode when all
+   * subchannels have failed to connect at least once, and it stays in that
+   * mode until a connection attempt is successful. While in sticky TF mode,
+   * the LB policy continuously attempts to connect to all of its subchannels.
+   */
+  private stickyTransientFailureMode = false;
+
+  /**
+   * Indicates whether we called channelControlHelper.requestReresolution since
+   * the last call to updateAddressList
+   */
+  private requestedResolutionSinceLastUpdate = false;
+
+  /**
+   * The most recent error reported by any subchannel as it transitioned to
+   * TRANSIENT_FAILURE.
+   */
+  private lastError: string | null = null;
+
+  private latestAddressList: SubchannelAddress[] | null = null;
+
+  /**
+   * Load balancer that attempts to connect to each backend in the address list
+   * in order, and picks the first one that connects, using it for every
+   * request.
+   * @param channelControlHelper `ChannelControlHelper` instance provided by
+   *     this load balancer's owner.
+   */
+  constructor(private readonly channelControlHelper: ChannelControlHelper) {
+    this.connectionDelayTimeout = setTimeout(() => {}, 0);
+    clearTimeout(this.connectionDelayTimeout);
+  }
+
+  private allChildrenHaveReportedTF(): boolean {
+    return this.children.every(child => child.hasReportedTransientFailure);
+  }
+
+  private calculateAndReportNewState() {
+    if (this.currentPick) {
+      this.updateState(
+        ConnectivityState.READY,
+        new PickFirstPicker(this.currentPick)
+      );
+    } else if (this.children.length === 0) {
+      this.updateState(ConnectivityState.IDLE, new QueuePicker(this));
+    } else {
+      if (this.stickyTransientFailureMode) {
+        this.updateState(
+          ConnectivityState.TRANSIENT_FAILURE,
+          new UnavailablePicker({details: `No connection established. Last error: ${this.lastError}`})
+        );
+      } else {
+        this.updateState(ConnectivityState.CONNECTING, new QueuePicker(this));
+      }
+    }
+  }
+
+  private requestReresolution() {
+    this.requestedResolutionSinceLastUpdate = true;
+    this.channelControlHelper.requestReresolution();
+  }
+
+  private maybeEnterStickyTransientFailureMode() {
+    if (!this.allChildrenHaveReportedTF()) {
+      return;
+    }
+    if (!this.requestedResolutionSinceLastUpdate) {
+      /* Each time we get an update we reset each subchannel's
+       * hasReportedTransientFailure flag, so the next time we get to this
+       * point after that, each subchannel has reported TRANSIENT_FAILURE
+       * at least once since then. That is the trigger for requesting
+       * reresolution, whether or not the LB policy is already in sticky TF
+       * mode. */
+      this.requestReresolution();
+    }
+    if (this.stickyTransientFailureMode) {
+      return;
+    }
+    this.stickyTransientFailureMode = true;
+    for (const { subchannel } of this.children) {
+      subchannel.startConnecting();
+    }
+    this.calculateAndReportNewState();
+  }
+
+  private removeCurrentPick() {
+    if (this.currentPick !== null) {
+      /* Unref can cause a state change, which can cause a change in the value
+       * of this.currentPick, so we hold a local reference to make sure that
+       * does not impact this function. */
+      const currentPick = this.currentPick;
+      this.currentPick = null;
+      currentPick.unref();
+      currentPick.removeConnectivityStateListener(this.subchannelStateListener);
+      this.channelControlHelper.removeChannelzChild(
+        currentPick.getChannelzRef()
+      );
+    }
+  }
+
+  private onSubchannelStateUpdate(
+    subchannel: SubchannelInterface,
+    previousState: ConnectivityState,
+    newState: ConnectivityState,
+    errorMessage?: string
+  ) {
+    if (this.currentPick?.realSubchannelEquals(subchannel)) {
+      if (newState !== ConnectivityState.READY) {
+        this.removeCurrentPick();
+        this.calculateAndReportNewState();
+        this.requestReresolution();
+      }
+      return;
+    }
+    for (const [index, child] of this.children.entries()) {
+      if (subchannel.realSubchannelEquals(child.subchannel)) {
+        if (newState === ConnectivityState.READY) {
+          this.pickSubchannel(child.subchannel);
+        }
+        if (newState === ConnectivityState.TRANSIENT_FAILURE) {
+          child.hasReportedTransientFailure = true;
+          if (errorMessage) {
+            this.lastError = errorMessage;
+          }
+          this.maybeEnterStickyTransientFailureMode();
+          if (index === this.currentSubchannelIndex) {
+            this.startNextSubchannelConnecting(index + 1);
+          }
+        }
+        child.subchannel.startConnecting();
+        return;
+      }
+    }
+  }
+
+  private startNextSubchannelConnecting(startIndex: number) {
+    clearTimeout(this.connectionDelayTimeout);
+    if (this.triedAllSubchannels) {
+      return;
+    }
+    for (const [index, child] of this.children.entries()) {
+      if (index >= startIndex) {
+        const subchannelState = child.subchannel.getConnectivityState();
+        if (
+          subchannelState === ConnectivityState.IDLE ||
+          subchannelState === ConnectivityState.CONNECTING
+        ) {
+          this.startConnecting(index);
+          return;
+        }
+      }
+    }
+    this.triedAllSubchannels = true;
+    this.maybeEnterStickyTransientFailureMode();
+  }
+
+  /**
+   * Have a single subchannel in the `subchannels` list start connecting.
+   * @param subchannelIndex The index into the `subchannels` list.
+   */
+  private startConnecting(subchannelIndex: number) {
+    clearTimeout(this.connectionDelayTimeout);
+    this.currentSubchannelIndex = subchannelIndex;
+    if (
+      this.children[subchannelIndex].subchannel.getConnectivityState() ===
+      ConnectivityState.IDLE
+    ) {
+      trace(
+        'Start connecting to subchannel with address ' +
+          this.children[subchannelIndex].subchannel.getAddress()
+      );
+      process.nextTick(() => {
+        this.children[subchannelIndex]?.subchannel.startConnecting();
+      });
+    }
+    this.connectionDelayTimeout = setTimeout(() => {
+      this.startNextSubchannelConnecting(subchannelIndex + 1);
+    }, CONNECTION_DELAY_INTERVAL_MS).unref?.();
+  }
+
+  private pickSubchannel(subchannel: SubchannelInterface) {
+    if (this.currentPick && subchannel.realSubchannelEquals(this.currentPick)) {
+      return;
+    }
+    trace('Pick subchannel with address ' + subchannel.getAddress());
+    this.stickyTransientFailureMode = false;
+    if (this.currentPick !== null) {
+      this.currentPick.unref();
+      this.channelControlHelper.removeChannelzChild(
+        this.currentPick.getChannelzRef()
+      );
+      this.currentPick.removeConnectivityStateListener(
+        this.subchannelStateListener
+      );
+    }
+    this.currentPick = subchannel;
+    subchannel.ref();
+    this.channelControlHelper.addChannelzChild(subchannel.getChannelzRef());
+    this.resetSubchannelList();
+    clearTimeout(this.connectionDelayTimeout);
+    this.calculateAndReportNewState();
+  }
+
+  private updateState(newState: ConnectivityState, picker: Picker) {
+    trace(
+      ConnectivityState[this.currentState] +
+        ' -> ' +
+        ConnectivityState[newState]
+    );
+    this.currentState = newState;
+    this.channelControlHelper.updateState(newState, picker);
+  }
+
+  private resetSubchannelList() {
+    for (const child of this.children) {
+      if (!(this.currentPick && child.subchannel.realSubchannelEquals(this.currentPick))) {
+        /* The connectivity state listener is the same whether the subchannel
+         * is in the list of children or it is the currentPick, so if it is in
+         * both, removing it here would cause problems. In particular, that
+         * always happens immediately after the subchannel is picked. */
+        child.subchannel.removeConnectivityStateListener(
+          this.subchannelStateListener
+        );
+      }
+      /* Refs are counted independently for the children list and the
+       * currentPick, so we call unref whether or not the child is the
+       * currentPick. Channelz child references are also refcounted, so
+       * removeChannelzChild can be handled the same way. */
+      child.subchannel.unref();
+      this.channelControlHelper.removeChannelzChild(
+        child.subchannel.getChannelzRef()
+      );
+    }
+    this.currentSubchannelIndex = 0;
+    this.children = [];
+    this.triedAllSubchannels = false;
+    this.requestedResolutionSinceLastUpdate = false;
+  }
+
+  private connectToAddressList(addressList: SubchannelAddress[]) {
+    const newChildrenList = addressList.map(address => ({
+      subchannel: this.channelControlHelper.createSubchannel(address, {}),
+      hasReportedTransientFailure: false,
+    }));
+    /* Ref each subchannel before resetting the list, to ensure that
+     * subchannels shared between the list don't drop to 0 refs during the
+     * transition. */
+    for (const { subchannel } of newChildrenList) {
+      subchannel.ref();
+      this.channelControlHelper.addChannelzChild(subchannel.getChannelzRef());
+    }
+    this.resetSubchannelList();
+    this.children = newChildrenList;
+    for (const { subchannel } of this.children) {
+      subchannel.addConnectivityStateListener(this.subchannelStateListener);
+      if (subchannel.getConnectivityState() === ConnectivityState.READY) {
+        this.pickSubchannel(subchannel);
+        return;
+      }
+    }
+    for (const child of this.children) {
+      if (
+        child.subchannel.getConnectivityState() ===
+        ConnectivityState.TRANSIENT_FAILURE
+      ) {
+        child.hasReportedTransientFailure = true;
+      }
+    }
+    this.startNextSubchannelConnecting(0);
+    this.calculateAndReportNewState();
+  }
+
+  updateAddressList(
+    addressList: SubchannelAddress[],
+    lbConfig: LoadBalancingConfig
+  ): void {
+    if (!(lbConfig instanceof PickFirstLoadBalancingConfig)) {
+      return;
+    }
+    /* Previously, an update would be discarded if it was identical to the
+     * previous update, to minimize churn. Now the DNS resolver is
+     * rate-limited, so that is less of a concern. */
+    if (lbConfig.getShuffleAddressList()) {
+      addressList = shuffled(addressList);
+    }
+    this.latestAddressList = addressList;
+    this.connectToAddressList(addressList);
+  }
+
+  exitIdle() {
+    if (this.currentState === ConnectivityState.IDLE && this.latestAddressList) {
+      this.connectToAddressList(this.latestAddressList);
+    }
+  }
+
+  resetBackoff() {
+    /* The pick first load balancer does not have a connection backoff, so this
+     * does nothing */
+  }
+
+  destroy() {
+    this.resetSubchannelList();
+    this.removeCurrentPick();
+  }
+
+  getTypeName(): string {
+    return TYPE_NAME;
+  }
+}
+
+export function setup(): void {
+  registerLoadBalancerType(
+    TYPE_NAME,
+    PickFirstLoadBalancer,
+    PickFirstLoadBalancingConfig
+  );
+  registerDefaultLoadBalancerType(TYPE_NAME);
+}