lib/instrumentation/modules/mysql2.js

/*
 * Copyright Elasticsearch B.V. and other contributors where applicable.
 * Licensed under the BSD 2-Clause License; you may not use this file except in
 * compliance with the BSD 2-Clause License.
 */

'use strict';

var semver = require('semver');
var sqlSummary = require('sql-summary');

var shimmer = require('../shimmer');
var symbols = require('../../symbols');
var { getDBDestination } = require('../context');

module.exports = function (mysql2, agent, { version, enabled }) {
  if (!enabled) {
    return mysql2;
  }
  if (!semver.satisfies(version, '>=1 <4')) {
    agent.logger.debug(
      'mysql2 version %s not supported - aborting...',
      version,
    );
    return mysql2;
  }

  var ins = agent._instrumentation;

  // mysql2@3.11.5 added BaseConnection class which is extended by Connection
  // but is not in the public API so we need to extract it via prototype chain
  // ref: https://github.com/sidorares/node-mysql2/pull/3081
  const baseClass = Object.getPrototypeOf(mysql2.Connection);
  const baseProto = baseClass.prototype;
  const hasQuery = typeof baseProto?.query === 'function';
  const hasExec = typeof baseProto?.execute === 'function';
  const shouldPatchBase = hasQuery && hasExec;

  if (shouldPatchBase) {
    shimmer.wrap(baseProto, 'query', wrapQuery);
    shimmer.wrap(baseProto, 'execute', wrapQuery);
  } else {
    shimmer.wrap(mysql2.Connection.prototype, 'query', wrapQuery);
    shimmer.wrap(mysql2.Connection.prototype, 'execute', wrapQuery);
  }

  return mysql2;

  function wrapQuery(original) {
    return function wrappedQuery(sql, values, cb) {
      agent.logger.debug('intercepted call to mysql2.%s', original.name);

      var span = ins.createSpan(null, 'db', 'mysql', 'query', {
        exitSpan: true,
      });
      if (!span) {
        return original.apply(this, arguments);
      }

      if (this[symbols.knexStackObj]) {
        span.customStackTrace(this[symbols.knexStackObj]);
        this[symbols.knexStackObj] = null;
      }

      let hasCallback = false;
      const wrapCallback = function (origCallback) {
        hasCallback = true;
        return ins.bindFunction(function wrappedCallback(_err) {
          span.end();
          return origCallback.apply(this, arguments);
        });
      };

      let host, port, user, database;
      if (typeof this.config === 'object') {
        ({ host, port, user, database } = this.config);
      }
      span._setDestinationContext(getDBDestination(host, port));

      let sqlStr;
      switch (typeof sql) {
        case 'string':
          sqlStr = sql;
          break;
        case 'object':
          // `mysql2.{query,execute}` support the only arg being an instance
          // of the internal mysql2 `Command` object.
          if (typeof sql.onResult === 'function') {
            sql.onResult = wrapCallback(sql.onResult);
          }
          sqlStr = sql.sql;
          break;
        case 'function':
          arguments[0] = wrapCallback(sql);
          break;
      }
      if (sqlStr) {
        span.setDbContext({
          type: 'sql',
          instance: database,
          user,
          statement: sqlStr,
        });
        span.name = sqlSummary(sqlStr);
      } else {
        span.setDbContext({ type: 'sql', instance: database, user });
      }

      if (typeof values === 'function') {
        arguments[1] = wrapCallback(values);
      } else if (typeof cb === 'function') {
        arguments[2] = wrapCallback(cb);
      }
      const spanRunContext = ins.currRunContext().enterSpan(span);
      const result = ins.withRunContext(
        spanRunContext,
        original,
        this,
        ...arguments,
      );

      if (result && !hasCallback) {
        ins.bindEmitter(result);
        shimmer.wrap(result, 'emit', function (origEmit) {
          return function (event) {
            switch (event) {
              case 'error':
              case 'close':
              case 'end':
                span.end();
            }
            return origEmit.apply(this, arguments);
          };
        });
      }

      return result;
    };
  }
};