CartoDB-SQL-API/app/services/stream_copy.js

90 lines
2.5 KiB
JavaScript

'use strict';
const PSQL = require('cartodb-psql');
const copyTo = require('pg-copy-streams').to;
const copyFrom = require('pg-copy-streams').from;
const ACTION_TO = 'to';
const ACTION_FROM = 'from';
const DEFAULT_TIMEOUT = "'5h'";
const cancelQuery = pid => `SELECT pg_cancel_backend(${pid})`;
const timeoutQuery = timeout => `SET statement_timeout=${timeout}`;
module.exports = class StreamCopy {
constructor(sql, userDbParams, logger) {
this.dbParams = Object.assign({}, userDbParams, {
port: global.settings.db_batch_port || userDbParams.port
});
this.sql = sql;
this.stream = null;
this.timeout = global.settings.copy_timeout || DEFAULT_TIMEOUT;
this.logger = logger;
}
static get ACTION_TO() {
return ACTION_TO;
}
static get ACTION_FROM() {
return ACTION_FROM;
}
getPGStream(action, callback) {
this.action = action;
const pg = new PSQL(this.dbParams);
pg.connect((err, client, done) => {
if (err) {
return callback(err);
}
client.query(timeoutQuery(this.timeout), (err) => {
if (err) {
return callback(err);
}
this.clientProcessID = client.processID;
this.stream = action === ACTION_TO ? copyTo(this.sql) : copyFrom(this.sql);
const pgstream = client.query(this.stream);
if (action === ACTION_TO) {
pgstream.on('end', () => done());
} else if (action === ACTION_FROM) {
pgstream.on('finish', () => done());
}
pgstream.on('error', err => done(err));
callback(null, pgstream);
});
});
}
getRowCount() {
return this.stream.rowCount;
}
cancel () {
const pid = this.clientProcessID;
const pg = new PSQL(this.dbParams);
pg.query(cancelQuery(pid), (err, result) => {
if (err) {
return this.logger.error(err);
}
const actionType = this.action === ACTION_TO ? ACTION_TO : ACTION_FROM;
const isCancelled = result.rows[0].pg_cancel_backend;
if (!isCancelled) {
return this.logger.error(new Error(`Unable to cancel "copy ${actionType}" stream query (pid: ${pid})`));
}
return this.logger.info(`Canceled "copy ${actionType}" stream query successfully (pid: ${pid})`);
});
}
};