p-cost

p-cost

How long will a Promise to be resolved(rejected) ?

When I used nodejs for backend development，I always create many promises to interact between multiple systems, such as database, or some other systems. These systems have different response times，in other word， these promises consume different lengths of time, some promises will take long time until it resolved, and some promises would only take very short time. I need a tool to count the length of each created promise cost。

So I extend the ES6 Promise to resolve this problem.

Examples

basic usage

new Promise(resolve => {
  setTimeout(resolve, 1000);
});
//output: anonymous ==> 1004ms at /p-cost/examples/stdout.example.js:6

custom name

new Promise(resolve => {
  setTimeout(resolve, 1000);
}, {name: "p-cost"});
//output: p-cost ==> 1003ms at /p-cost/examples/stdout.example.js:11

sum the time cost in same promise chain

new Promise(resolve => {
  setTimeout(resolve, 1000);
}, {
  name: "cost",
  sum: true    // sum the time cost in the promise chain
}).then(() => { // cost-#1
  // do something here
}).then(() => { // cost-#2
  // do something here
});
// output:
//         cost ==> 1009ms /p-cost/examples/name.example.js:15
//         cost-#1 ==> 1011ms /p-cost/examples/name.example.js:20
//         cost-#2 ==> 1010ms /p-cost/examples/name.example.js:22

custom notifier

new Promise(resolve => {
  setTimeout(resolve, 1000);
}, {
  name: "bunyan1000",
  notifier: {
    notify: bunyanNotifier,
    notifyOpt: {name: "overtime promise"}
  }
});

// output
// {
//   "name": "bunyan1000",
//   "hostname": "qeesungdeMacBook-Pro.local",
//   "pid": 18100,
//   "level": 30,
//   "cost": "1004ms",
//   "location": {
//     "file": "/p-cost/examples/bunyan.example.js",
//     "line": "7"
//   },
//   "msg": "",
//   "time": "2017-06-03T16:05:35.527Z",
//   "v": 0
// }

more examples can be found in example directory

Usage

new Promise((resolve, reject) => {}, options);

options

{
  name: "hello",
  timeout: 500,
  sum: true,
  notifer: {
    notify: () => {}
    notifyOpt: {}
  }
}

name	type	required	default	description
timeout	boolean	false	1000	if promise resolved time exceed timeoutms, notify function will be called
name	string	false	"anonymous"	promise name
sum	boolean	false	false	if sum the time cost in same promise chain
notifier.notify	function	false	stdoutNotifier	the way to notify user if timeout
notifier.notifyOpt	object	false	null	will pass to notifier.notify function as argument

options.timeout

Not all promises will notify the user the time it spent, just the promise that exceed the timeout, You can set the timeout to control the threshold of the reminder.

// default timeout is 1000ms
new Promise((resolve) => {
  setTimeout(resolve, 1000);
});
//output: anonymous ==> 1004ms at /p-cost/examples/stdout.example.js:6

// custom timeout
new Promise((resolve) => {
  setTimeout(resolve, 500);
}, {name: "stdout-500", timeout: 300});
//output: stdout-500 ==> 506ms at /p-cost/examples/stdout.example.js:16

options.name

Give promise a custom name，you can make it easier to identify those notify message.

// default promise name
new Promise((resolve) => {
  setTimeout(resolve, 1000);
});
//output: anonymous ==> 1004ms at /p-cost/examples/stdout.example.js:6

// custom promise name
new Promise(resolve => {
  setTimeout(resolve, 1000);
}, {
  name: "cost"
});
// output: cost ==> 1005ms at /p-cost/examples/name.example.js:8

// auto increment suffix serial number
new Promise(resolve => {
  setTimeout(resolve, 1000);
}, {
  name: "cost",
  sum: true    // sum the time cost in the promise chain
}).then(() => { // cost-#1
  // do something here
}).then(() => { // cost-#2
  // do something here
});
// output:
//         cost ==> 1009ms /p-cost/examples/name.example.js:15
//         cost-#1 ==> 1011ms /p-cost/examples/name.example.js:20
//         cost-#2 ==> 1010ms /p-cost/examples/name.example.js:22

options.sum

Note: because every promise only have three status: pending, fullfiled, rejected, so the then function will return a new Promise, and this new Promise will be resolved after previous promises were fullfilled, so the new Promise spent time is the sum of previous promises spent time and it own spent.

If the sum is true, the prmise in the same promise chain spent time is the sum of previous promises spent time and it own spent. If the sum is false, the promise in the same promise chain spent time is only the time it own spent.

// sum the time cost
new Promise(resolve => {
  setTimeout(resolve, 1000);
},{
  sum: true
}).then(() => {
  // do something here
}).then(() => {
  // do something here
});
// output:
//         anonymous ==> 1006ms at /p-cost/examples/sum.example.js:9
//         anonymous-#1 ==> 1010ms at /p-cost/examples/sum.example.js:11
//         anonymous-#2 ==> 1010ms at /p-cost/examples/sum.example.js:13

// do not sum the time cost
new Promise(resolve => {
  setTimeout(resolve, 1000);
},{
  sum: false
}).then(() => {
  // do something here
}).then(() => {
  // do something here
});
// output: anonymous ==> 1008ms at /p-cost/examples/sum.example.js:24

options.notifier

When the time the promise spent exceed timeout, the notifier.notify function will be called to notify the user.

provided notifer

• stdoutNotifer notify the user by stdout, example
• bunyanNotifer notify the user by bunyan, example
• emailNotifer notify the user by email., example

how to custom a notifier

notifier is just a normal object, and the notifier.notify is a normal function. and notify function will be called with:

• name, promise name
• cost, the promise tim cost
• caller, call stack, promise location
  • caller.file the file define the promise
  • caller.line the line define the promise
• options, notifyOptions

let customNotify = (name, cost, caller, options) => {
  
}