`waitForIndex` 不能正常工作

Question

当启动下面的脚本时，我遇到了一个卡在

上的错误

Something bad heppened while waiting for index created
Index `createdAt` was not found on table `olive.todos`
r.table("todos").indexWait("createdAt")
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

但是再次启动脚本，我没有问题。

这是RethinkDB的问题还是我的？并告诉我解决方法。

const createIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexList().contains(indexName)
    .do(containsIndex =>
      r.branch(
        containsIndex,
        { created: 0 },
        r.table(tableName).indexCreate(indexName)
      )
    )
    ...

const waitForIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexWait(indexName)
    ...

export const setup = startApp => {
  r.connect(config.rethinkdb)
    ...
    .then(conn => {
      Promise.all([
        createIndex(conn, 'todos', 'createdAt'),
        createIndex(conn, 'days', 'date'),
      ]);
      return conn;
    })
    .then(conn =>
      Promise.all([
        waitForIndex(conn, 'todos', 'createdAt'),
        waitForIndex(conn, 'days', 'date'),
      ])
    )
    ...
};

Answer 1

我认为一切看起来都不错，但您遗漏了查询的 .run(conn) 部分。将其更改为此应该可以做到：

const createIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexList().contains(indexName)
    .do(containsIndex =>
      r.branch(
        containsIndex,
        { created: 0 },
        r.table(tableName).indexCreate(indexName)
      )
    ).run(conn);
    ...

const waitForIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexWait(indexName).run(conn)
    ...

export const setup = startApp => {
  r.connect(config.rethinkdb)
    ...
    .then(conn => {
      Promise.all([
        createIndex(conn, 'todos', 'createdAt'),
        createIndex(conn, 'days', 'date'),
      ]);
      return conn;
    })
    .then(conn =>
      Promise.all([
        waitForIndex(conn, 'todos', 'createdAt'),
        waitForIndex(conn, 'days', 'date'),
      ])
    )
    ...
};

Answer 2

你好像混杂了不同Promise的APIAPI。我没有看到你从任何地方导入 Promise。我猜你使用的是内置 JavaScript Promise https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

当您使用 Promise.all 时，您必须将其与 then 链接起来，而不是使用 return 作为下一个语句。使用 resolver/reject.

链接到 then

您的代码在 Promise.all 之后使用 return，但您没有调用 then，因此它 returns 并且索引尚未准备好尚未创建。

此代码有效：

import r from 'rethinkdb';
import config from '../config';

const createDatabase = (conn, name) =>
  r.dbList().contains(name)
    .do(containsDb =>
      r.branch(
        containsDb,
        { created: 0 },
        r.dbCreate(name)
      )
    )
    .run(conn)
    .error(err => {
      console.log(`Could not create ${name} DB`);
      console.log(err.message || 'Something bad happened');
      process.exit(1);
    });

const createTable = (conn, name) =>
  r.tableList().contains(name)
    .do(containsTable =>
      r.branch(
        containsTable,
        { created: 0 },
        r.tableCreate(name)
      )
    )
    .run(conn)
    .error(err => {
      console.log(`Could not create ${name} table`);
      console.log(err.message || 'Somthing bad happened');
      process.exit(1);
    });

const createIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexList().contains(indexName)
    .do(containsIndex =>
      r.branch(
        containsIndex,
        { created: 0 },
        r.table(tableName).indexCreate(indexName)
      )
    )
    .run(conn)
    .error(err => {
      console.log(`Could not crate index ${indexName} in ${tableName}`);
      console.log(err.message || 'Something bad happened');
      process.exit(1);
    });

const waitForIndex = (conn, tableName, indexName) =>
  r.table(tableName).indexWait(indexName)
    .run(conn)
    .error(err => {
      console.log('Something bad happened while waiting for index created');
      console.log(err.message || 'Something bad happened');
      process.exit(1);
    });

export const setup = startApp => {
  r.connect(config.rethinkdb)
    .then(conn => {
      createDatabase(conn, 'test');
      return conn;
    })
    .then(conn => {
      return Promise.all([
        createTable(conn, 'todos'),
        createTable(conn, 'days'),
      ]).then((result) => conn, (reason) => conn)
    })
    .then(conn => {
      return Promise.all([
        createIndex(conn, 'todos', 'createdAt'),
        createIndex(conn, 'days', 'date'),
      ]).then(() =>  conn, () => conn)
    })
    .then(conn => {
        return Promise.all([
          waitForIndex(conn, 'todos', 'createdAt'),
          waitForIndex(conn, 'days', 'date'),
        ])
      }
    )
    .then(() => {
      console.log('DB and tables are available, starting Koa ...');
      startApp();
    })
    .error(err => {
      console.log('Could not open a connection to initiailize the database');
      console.log(err.message || 'Something bad happened');
      process.exit(1);
    });
};

setup()

注意我们必须使用 then 来传递 conn 对象，而不是返回

`waitForIndex` 不能正常工作

`waitForIndex` does not work correctly

rethinkdb

rethinkdb-javascript