Openwhisk and Minio with packaged action issue

Question

I am trying to create an openwhisk action that uses the minio server. In order to do that I have to package my action as a nodeJs module cause minio is not supported by openwhisk. My index.js file is the following:

function myAction(){
    const minio = require("minio")
    const minioClient = new minio.Client({
        endPoint: 'myIP',
        port: 9000,
        secure: false,
        accessKey: '###########',
        secretKey: '###########'
    });

    minioClient.listBuckets(function(err, buckets) {
        if (err) return console.log(err)
        return {payload: buckets}
    })

}

exports.main = myAction;

When I am invoking this action I get {}. Do you have any ideas why is this happening? Any suggestions of how can I solve it?

Answer 1

An OpenWhisk action expects you to return a Promise, if you're doing something asynchronously.

In your case, you'll need to construct a promise which is resolved once the listBuckets method is done (generally this means: You need to resolve it in the callback).

function myAction(){
    const minio = require("minio")
    const minioClient = new minio.Client({
        endPoint: 'myIP',
        port: 9000,
        secure: false,
        accessKey: '###########',
        secretKey: '###########'
    });

    return new Promise(function(resolve, reject) {
        minioClient.listBuckets(function(err, buckets) {
            if (err) {
                reject(err);
            } else {
                resolve({payload: buckets});
            }
        });
    });
}

exports.main = myAction;

(Untested code).