CODEWITHSUNDEEP
javascriptnode.jspromiserestifybluebird
Passionate Engineer
Passionate Engineer

Reputation: 10412

How to do parallel async multiple requests at once with Promises in Node

Array and loops through but I want to be able to run all of them in parallel instead as I don't want to run one after another.

I basically want to store all endpoint calls status codes, body and time as array and return them as results regardless of there are errors or not in the endpoint.

I'm using Bluebird, how can I use its features to solve this issue?

Upvotes: 4

Views: 9167

Answers (4)

Esailija
Esailija

Reputation: 140210

You can use Promise.map with .bind:

function getComponentStatuses(componentsToCheck) {
    return Promise.map(componentsToCheck, function() {
        var start = Date.now();
        return getAsync({
            url: component.endpoint,
            timeout: component.timeout
        })
        .bind({
             name: component.name,
             status: null,
             body: null,
             time: null
        })
        .spread(function(response, body){
            Logger.info('GET took ' + end + 'ms.');
            this.status = response.statusCode;
            this.body = body;
            return this;
        })
        .catch(function(e) { return this; })
        .finally(function() { this.time = Date.now() - start; })
    });
}

Note that your timing method is incorrect because the http agent might throttle requests.

Upvotes: 6

Passionate Engineer
Passionate Engineer

Reputation: 10412

Found the solution.

Use .settle

Upvotes: 0

user3748808
user3748808

Reputation:

Bluebird supports multiple concurrent Promises.

See the reference at: https://github.com/petkaantonov/bluebird/blob/master/API.md#promisejoinpromisethenablevalue-promises-function-handler---promise

There are two ways to do it:

.all() - good for a dynamic number of promises

.join() - good for a fixed number of promises and as for Bluebird's documentation, it supplies a better performance than .all() method.

From bluebird's documentation:

 var Promise = require("bluebird");
 var join = Promise.join;

join(getPictures(), getComments(), getTweets(),
function(pictures, comments, tweets) {
console.log("in total: " + pictures.length + comments.length + tweets.length);
});

Upvotes: 4

Phong Dao
Phong Dao

Reputation: 139

I use q Promise Maybe help

return q.all([function or value1, function or value 2, ......])
.spread(function (result1, result2, ....) {
   // do somethine
})

............

Upvotes: -1

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