src/plugins/PgPlugin.ts

/*!
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 SwPlugin, {wrapEmit, wrapCallback, wrapPromise} from '../core/SwPlugin';
import ContextManager from '../trace/context/ContextManager';
import { Component } from '../trace/Component';
import Tag from '../Tag';
import { SpanLayer } from '../proto/language-agent/Tracing_pb';
import PluginInstaller from '../core/PluginInstaller';
import agentConfig from '../config/AgentConfig';

class MySQLPlugin implements SwPlugin {
  readonly module = 'pg';
  readonly versions = '*';

  install(installer: PluginInstaller): void {
    const Client = installer.require('pg/lib/client');

    let Cursor: any;

    try {
      Cursor = installer.require('pg-cursor');
    } catch { /* Linter food */ }

    const _query = Client.prototype.query;

    Client.prototype.query = function(config: any, values: any, callback: any) {
      let query: any;

      const host = `${this.host}:${this.port}`;
      const span = ContextManager.current.newExitSpan('pg/query', host, Component.POSTGRESQL);

      span.start();

      try {
        span.component = Component.POSTGRESQL;
        span.layer = SpanLayer.DATABASE;
        span.peer = host;

        span.tag(Tag.dbType('PostgreSQL'));
        span.tag(Tag.dbInstance(`${this.connectionParameters.database}`));

        let _sql: any;
        let _values: any;

        if (typeof config === 'string')
          _sql = config;

        else if (config !== null && config !== undefined) {
          _sql    = config.text;
          _values = config.values;

          if (typeof config.callback === 'function')
            config.callback = wrapCallback(span, config.callback, 0);
        }

        if (typeof values === 'function')
          values = wrapCallback(span, values, 0);
        else if (_values !== undefined)
          _values = values;

        if (typeof callback === 'function')
          callback = wrapCallback(span, callback, 0);

        span.tag(Tag.dbStatement(`${_sql}`));

        if (agentConfig.sqlTraceParameters && _values) {
          let vals = _values.map((v: any) => v === undefined ? 'undefined' : JSON.stringify(v)).join(', ');

          if (vals.length > agentConfig.sqlParametersMaxLength)
            vals = vals.slice(0, agentConfig.sqlParametersMaxLength) + ' ...';

            span.tag(Tag.dbSqlParameters(`[${vals}]`));
        }

        query = _query.call(this, config, values, callback);

        if (query) {
          if (Cursor && query instanceof Cursor)
            wrapEmit(span, query, true, 'end');
          else if (typeof query.then === 'function')  // generic Promise check
            query = wrapPromise(span, query);
          // else we assume there was a callback
        }

      } catch (e) {
        span.error(e);
        span.stop();

        throw e;
      }

      span.async();

      return query;
    };
  }
}

// noinspection JSUnusedGlobalSymbols
export default new MySQLPlugin();