Javascript 停止NodeJs promise while循环中的多个服务控制器查询
我正在尝试从节点脚本启动windows服务。此服务有挂起的坏习惯，有时需要重试才能成功启动。我有一个承诺，而循环设置（请随时建议一个更好的方式）。我遇到的问题是，对于每个循环，Javascript 停止NodeJs promise while循环中的多个服务控制器查询,javascript,node.js,promise,gulp,service-control-manager,Javascript,Node.js,Promise,Gulp,Service Control Manager,我正在尝试从节点脚本启动windows服务。此服务有挂起的坏习惯，有时需要重试才能成功启动。我有一个承诺，而循环设置（请随时建议一个更好的方式）。我遇到的问题是，对于每个循环，sc.pollInterval输出在控制台中写入重复的结果。下面是我在控制台中看到的重复内容的示例，这是在循环中的第二次迭代之后，我希望它只显示该内容一次 sc \\abnf34873 start ColdFusion 10 Application Server sc \\abnf34873 queryex ColdFu
sc.pollIntervalsc \\abnf34873 start ColdFusion 10 Application Server
sc \\abnf34873 queryex ColdFusion 10 Application Server
SERVICE_NAME: ColdFusion 10 Application Server
TYPE : 10 WIN32_OWN_PROCESS
STATE : 2 START_PENDING
(NOT_STOPPABLE, NOT_PAUSABLE, IGNORES_SHUTDOWN)
WIN32_EXIT_CODE : 0 (0x0)
SERVICE_EXIT_CODE : 0 (0x0)
CHECKPOINT : 0x0
WAIT_HINT : 0x7d0
PID : 0
FLAGS :
SERVICE_NAME: ColdFusion 10 Application Server
TYPE : 10 WIN32_OWN_PROCESS
STATE : 2 START_PENDING
(NOT_STOPPABLE, NOT_PAUSABLE, IGNORES_SHUTDOWN)
WIN32_EXIT_CODE : 0 (0x0)
SERVICE_EXIT_CODE : 0 (0x0)
CHECKPOINT : 0x0
WAIT_HINT : 0x7d0
PID : 13772
FLAGS :
var retryCount = 0;
// Start the colfusion service
gulp.task('start-coldfusion-service', function(done) {
var serviceStarted = false;
console.log("Starting coldfusion service..");
// This says we're going to ask where it's at every 30 seconds until it's in the desired state.
sc.pollInterval(30);
sc.timeout(60);
retryCount = 0;
tryServiceStart().then(function(result) {
// process final result here
done();
}).catch(function(err) {
// process error here
});
});
function tryServiceStart() {
return startService().then(function(serviceStarted) {
if (serviceStarted == false) {
console.log("Retry Count: " + retryCount);
// Try again..
return tryServiceStart();
} else {
return result;
}
});
}
function startService() {
return new Promise(function(resolve, reject) {
var started = true;
// Make sure the coldfusion service exists on the target server
sc.query(targetServer, { name: 'ColdFusion 10 Application Server'}).done(function(services) {
// if the service exists and it is currentl stopped, then we're going to start it.
if (services.length == 1) {
var pid = services[0].pid;
if (services[0].state.name == 'STOPPED') {
sc.start(targetServer, 'ColdFusion 10 Application Server')
.catch(function(error) {
started = false;
console.log("Problem starting Coldfusion service! error message: " + error.message);
console.log("retrying...");
retryCount++;
if (parseInt(retryCount) > 2) {
throw Error(error.message);
}
})
.done(function(displayName) {
if (started) {
console.log('Coldfusion service started successfully!');
}
resolve(started);
});
} else if (services[0].state.name == 'START_PENDING') {
kill(pid, {force: true}).catch(function (err) {
console.log('Problem killing process..');
}).then(function() {
console.log('Killed hanging process..');
resolve(false);
});
}
} else {
console.log("Could not find the service in a stopped state.");
resolve(false);
}
});
});
}
我发现另一个名为
promise retrygulp.task('start-coldfusion-service', function(done) {
var serviceStarted = false;
console.log("Starting coldfusion service..");
// Since starting a service on another server isn't exactly fast, we have to poll the status of it.
// This says we're going to ask where it's at every 30 seconds until it's in the desired state.
sc.pollInterval(30);
sc.timeout(60);
promiseRetry({retries: 3}, function (retry, number) {
console.log('attempt number', number);
return startService()
.catch(function (err) {
console.log(err);
if (err.code === 'ETIMEDOUT') {
retry(err);
} else if (err === 'killedProcess') {
retry(err);
}
throw Error(err);
});
})
.then(function (value) {
done();
}, function (err) {
console.log("Unable to start the service after 3 tries!");
process.exit();
});
});
function startService() {
var errorMsg = "";
return new Promise(function(resolve, reject) {
var started = true;
// Make sure the coldfusion service exists on the target server
sc.query(targetServer, { name: 'ColdFusion 10 Application Server'}).done(function(services) {
// if the service exists and it is currentl stopped, then we're going to start it.
if (services.length == 1) {
var pid = services[0].pid;
if (services[0].state.name == 'STOPPED') {
sc.start(targetServer, 'ColdFusion 10 Application Server')
.catch(function(error) {
started = false;
errorMsg = error;
console.log("Problem starting Coldfusion service! error message: " + error.message);
console.log("retrying...");
})
.done(function(displayName) {
if (started) {
console.log('Coldfusion service started successfully!');
resolve(started);
} else {
reject(errorMsg);
}
});
} else if (services[0].state.name == 'START_PENDING') {
kill(pid, {force: true}).catch(function (err) {
console.log('Problem killing process..');
}).then(function() {
console.log('Killed hanging process..');
reject("killedProcess");
});
} else {
// Must already be started..
resolve(true);
}
} else {
console.log("Could not find the service in a stopped state.");
resolve(false);
}
});
});
}
不太清楚为什么会在控制台中得到重复的结果，但是下面是一些关于如何更好地编写代码的想法，主要是通过在最低级别上进行承诺 坚持原来的概念，我最终得到了这个 提示sc命令
- sc命令返回类似于promise的东西，但带有一个.done（）方法，该方法很可能不具有真正的.then（）方法的全部功能
- 将每个命令显示为
.xxxAsync（） - 通过采用每个命令的
作为.done
，Promise.resolve（）应该能够吸收命令返回的类似于Promise的内容。然后
- 如果服务已打开，承诺链将遵循其成功路径，否则将遵循其错误路径
- 无需测试
，即可检测成功路径中的错误情况结果
- 在此处编排重试
- 通过调用
和sc.query（）sc.start（） console.log（）- 抛出的错误将被捕获并记录回
tryServiceStart（）- 抛出的错误将被捕获并记录回
提供FWIW。可以根据需要随意采用/raid。service control manager软件包声称“所有命令都返回一个承诺”，但是文档（您的代码正确遵守了该文档）告诉我们，这些所谓的承诺包含
.done（）.catch（）.done（）的全部功能。然后（）.done（）.done（）.done（）kill（）kill（…）。catch（…）。然后（…）；catchthenkill（…）。然后（…）.catch（…）；reject（）错误字符串错误promise retrytryServiceStart（）Promise retry;(function() {
commands.forEach(command => {
sc[command].then = sc[command].done;
sc[command + 'Async'] = function() {
return Promise.resolve(sc[command](...arguments));
};
}).
}(['start', 'query'])); // add other commands as required
gulp.task('start-coldfusion-service', function(done) {
console.log('Starting coldfusion service..');
// This says we're going to ask where it's at every 30 seconds until it's in the desired state.
sc.pollInterval(30);
sc.timeout(60);
tryServiceStart(2) // tryServiceStart(maxRetries)
.then(done) // success! The service was started.
.catch(function(err) {
// the only error to end up here should be 'Maximum tries reached'.
console.err(err);
// process error here if necessary
});
});
function tryServiceStart(maxRetries) {
return startService()
// .then(() => {}) // success! No action required here, just stay on the success path.
.catch((error) => {
// all throws from startService() end up here
console.error(error); // log intermediate/final error
if(--maxRetries > 0) {
return tryServiceStart();
} else {
throw new Error('Maximum tries reached');
}
});
}
function startService() {
// Make sure the coldfusion service exists on the target server
return sc.queryAsync(targetServer, { name: 'ColdFusion 10 Application Server'})
.then((services) => {
// if the service exists and it is currently stopped, then start it.
if (services.length == 1) {
switch(services[0].state.name) {
case 'STOPPED':
return sc.startAsync(targetServer, 'ColdFusion 10 Application Server')
.catch((error) => {
throw new Error("Problem starting Coldfusion service! error message: " + error.message);
});
break;
case 'START_PENDING':
return kill(services[0].pid, { 'force': true })
.then(() => {
throw new Error('Killed hanging process..'); // successful kill but still an error as far as startService() is concerned.
})
.catch((err) => {
throw new Error('Problem killing process..');
});
break;
default:
throw new Error("Service not in a stopped state.");
}
} else {
throw new Error('Could not find the service.');
}
});
}