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/*
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 *  This file is part of CoCalc: Copyright © 2022 Sagemath, Inc.
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 *  License: MS-RSL – see LICENSE.md for details
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 */
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import getLogger from "@cocalc/backend/logger";
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import { newGauge } from "@cocalc/backend/metrics";
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import { PostgreSQL } from "./types";
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function getStatusGauge() {
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  return newGauge(
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    "database",
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    "db_latest_connection_ts_total",
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    "Last time the connect/disconnect event was emitted",
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    ["status"],
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  );
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}
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const L = getLogger("db:record-connect-error");
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// timestamp when the *first* disconnect event happend
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// a "connect" event will reset this to null
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let lastDisconnected: number | null = null;
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// ATTN: do not move/rename this function, since it is referenced in postgres-base.coffee
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export function recordDisconnected() {
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  L.debug("disconnected");
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  const now = Date.now();
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  try {
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    getStatusGauge().labels("disconnected").set(now);
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  } catch (err) {
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    L.debug("issue with database status gauge", err);
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  }
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  if (lastDisconnected == null) {
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    lastDisconnected = now;
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  }
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}
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// ATTN: do not move/rename this function, since it is referenced in postgres-base.coffee
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export function recordConnected() {
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  L.debug("connected");
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  try {
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    getStatusGauge().labels("connected").set(Date.now());
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  } catch (err) {
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    L.debug("issue with database status gauge", err);
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  }
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  lastDisconnected = null;
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}
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export function setupRecordConnectErrors(_db: PostgreSQL) {
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  // These event listeners are not robust. Somehow, a "removeAllListeners" or similar must trimp them up
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  // The problem arises when the database connection is dropped, reconnected, and dropped again:
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  // After the 2nd connection drop, the "disconnect" event is attempted to emit, but never appears here.
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  //db.on("connect", () => recordConnected());
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  //db.on("disconnect", () => recordDisconnected());
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}
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export function howLongDisconnectedMins(): number | undefined {
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  if (lastDisconnected == null) {
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    return undefined;
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  } else {
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    const last = lastDisconnected;
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    const now = Date.now();
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    const dtMin = (now - last) / 1000 / 60;
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    return dtMin;
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  }
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}
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