问题描述
所以我有一台服务器正在监听RabbitMQ请求:
So I have a server listening to RabbitMQ requests:
console.log(' [*] Waiting for messages in %s. To exit press CTRL+C', q);
channel.consume(q, async function reply(msg) {
const mongodbUserId = msg.content.toString();
console.log(' [x] Received %s', mongodbUserId);
await exec('./new_user_run_athena.sh ' + mongodbUserId, function(
error,
stdout,
stderr
) {
console.log('Running Athena...');
console.log('stdout: ' + stdout);
console.log('stderr: ' + stderr);
if (error !== null) {
console.log('exec error: ' + error);
}
});
console.log(
' Finished running Athena for mongodbUserId=%s',
mongodbUserId
);
channel.sendToQueue(
msg.properties.replyTo,
new Buffer(mongodbUserId),
{ correlationId: msg.properties.correlationId }
);
channel.ack(msg);
});
问题在于执行shell脚本 new_user_run_athena.sh 的等待调用发生在我打印出 mongodbUserId 的已完成运行的雅典娜之后.您可以在控制台日志中看到它的发生:
The problem is that the await call on executing the shell script new_user_run_athena.sh happens after I print out Finished running Athena for mongodbUserId. You can see it happening in the console log:
[*] Waiting for messages in run_athena_for_new_user_queue. To exit press CTRL+C
[x] Received 5aa96f36ed4f68154f3f2143
Finished running Athena for mongodbUserId=5aa96f36ed4f68154f3f2143
Running Athena...
stdout:
stderr:
在执行Shell脚本时是否甚至可以使用异步等待语法?
Is it even possible to use async await syntax on executing a shell script?
推荐答案
由于 exec 看起来需要回调，因此您可以使用该回调将其包装为promise.然后，您可以等待该承诺，而不必直接等待 exec 调用.因此，以您的示例为例，
Since exec looks like it takes a callback, you can use that to wrap it into a promise. Then you can await that promise instead of awaiting the exec call directly. So, for your example, something like:
// Await a new promise:
await new Promise((resolve, reject) => {
exec('./new_user_run_athena.sh ' + mongodbUserId, function(
error,
stdout,
stderr
) {
console.log('Running Athena...');
console.log('stdout: ' + stdout);
console.log('stderr: ' + stderr);
if (error !== null) {
console.log('exec error: ' + error);
// Reject if there is an error:
return reject(error);
}
// Otherwise resolve the promise:
resolve();
});
});
这篇关于如何在执行shell脚本时使用javascript async/await的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！