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How to fake AWS locally with LocalStack

Joseph Thomas on March 11, 2019

If you're anything like me, you prefer to avoid logging into the AWS console as much as possible. Did you set up your IAM root user with 2FA and co...
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Carlo Gino Catapang •

Great article, kudos to you mate. 1 issue in my case, image localstack/localstack did not have the web ui localhost:8080 during my testing. I needed to use localstack/localstack-full to enable web ui.

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Javier Marquez • • Edited

Thanks Joseph for this article, it really got me started with localstack.

It seems that the number of ports that localstack uses has grown since this article was written, and I found myself if problems because localhost:4592 wasn't forwarded in the example (STS in localstack's aws).

It took me a while to realize it was that! Could you update the example to forward all the new ports? Something like:

ports:
      - '4563-4599:4563-4599'
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Cheers!

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Joseph Thomas •

Just updated, thanks for letting me know!

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Salvador Hernandez • • Edited

Great Doc! Had issues creating s3 bucket, had to configure aws configure with

accessKeyId: '123'
secretAccessKey: 'xyz`
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otherwise it would throw the following error:
make_bucket failed: s3://demo-bucket Unable to locate credentials

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targei profile image
qiang •

Nice solution. However I met a problem , localhost:4572/ can show the bucket, but nothing on localhost:8055/



bcaf1ffd86f41161ca5fb16fd081034f
webfile



demo-bucket
2006-02-03T16:45:09.000Z


another problem is , when test the test-upload.js
it report below error :
"UnknownEndpoint: Inaccessible host: demo-bucket.localhost'. This service may not be available in theus-east-1' region."

I'm new novice of the S3 and docker, Could you point out how to set region for localhost s3 service.

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Michael Pablo Gomes da Silva •

Hi there!
I know that is 2020, but better later than never. So my solution for this problem was:
.env
AWS_ACCESS_KEY_ID='default'
AWS_SECRET_KEY='default'
AWS_BUCKET_NAME='demo-bucket'
AWS_REGION='us-west-2'
AWS_S3_ENDPOINT='localhost:4572'

aws.js
const AWS = require('aws-sdk')
require('dotenv').config()

const credentials = {
accessKeyId: process.env.AWS_ACCESS_KEY_ID,
secretAccessKey: process.env.AWS_SECRET_KEY,
}

const useLocal = process.env.NODE_ENV !== 'production'

const bucketName = process.env.AWS_BUCKET_NAME

const s3client = new AWS.S3({
credentials,
endpoint: process.env.AWS_S3_ENDPOINT,
region: process.env.AWS_REGION,
s3ForcePathStyle: true
/**
* When working locally, we'll use the Localstack endpoints. This is the one for S3.
* A full list of endpoints for each service can be found in the Localstack docs.
*/
})

const uploadFile = async (data, name) =>
new Promise((resolve) => {
s3client.upload(
{
Bucket: bucketName,
/*
include the bucket name here. For some reason Localstack needs it.
see: github.com/localstack/localstack/i...
*/
Key: ${bucketName}/${name},
Body: data,
},
(err, response) => {
if (err) throw err
resolve(response)
},
)
})

module.exports = uploadFile

Hope that might be helpful for someone else in the future.

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mcmule profile image
Marc Muller •

Many thanks for the article!

I had troubles: my app is running in a docker container and I was getting connection refused (ECONNREFUSED) when trying to reach the localstack container. After trying a lot of config variants, I ended up with this:

AWS.config.update({
    accessKeyId: '123',
    secretAccessKey: 'xyz',
    endpoint: 'host.docker.internal:4572',
    s3ForcePathStyle: true
});

Both endpoint and s3ForcePathStyle are important here. s3ForcePathStyle tells the sdk to use url of the from hostname/bucket instead of bucket.hostname.

Besides being the only configuration working for me, with this, I don't need to prepend bucketName in my params:

Key: `${bucketName}/${name}`

becomes

Key: `${name}`

This was not the intended effect (I was just trying to get a working connection between my app and the s3 container). Hope this can help someone else.

Thanks again for your article!

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Joseph Thomas • • Edited

Hi Marc, thanks for pointing this out! I've updated the article and the demo repo with these changes.

It's still working for me when I use http://localhost:4572 as the endpoint, so I left that as-is.

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mcmule profile image
Marc Muller •

Awesome!

With a few more experimentation, I'm now using both variants:

  • host.docker.internal when my app is dockerized (which happens when I'm TDD'ing, most of the time)
  • localhostwhen my app is not dockerized (happening on my CI testing job)
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nikola_janicijevic_ef1bf7 profile image
Nikola Janicijevic •

Nice work on this tutorial. I think that the last update of the localstack image move all ports to the 4566. Also there is a info that the dashboard will be removed in some of the upcoming releases.

Thanks for the work

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Jeff Martin •

Nice article, Thanks for the work. To access the web ui you need to use the full version of localstack ie:
image: localstack/localstack-full:latest
The localstack github also warns that the web ui has been deprecated and may be removed at some point.

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rkbadatya profile image
rkbadatya • • Edited

It's no longer available

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RichardDrury •

This is brilliant, so well written and completely idiot proofed (for the likes of me). We won't be using it for the JS app you have created but more to have a local dev environment where we can spin up a docker container with a database and another with the S3 stack on it so we can develope data feeds.

You have contributed to my learning.
Thanks

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Alexis Wilke • • Edited

What's missing in your article is the fact that credentials can be whatever. You do show how to set it up, but you do that AFTER the:

aws s3 mb url

When it's already necessary on that line. Also you do not explain the fact that localstack will accept totally whatever as credentials.

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goodidea profile image
Joseph Thomas •

Hi, thanks for pointing this out! I updated the setup with a new step:

Once the AWS CLI is installed, run aws configure to create some credentials. Even though we're talking to our "fake" local service, we still need credentials. You can enter real credentials (as described here), or dummy ones. Localstack requires that these details are present, but doesn't actually validate them.

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anaclaudiar •

Hi Joseph, great article! Thank you!
I think there is a small thing, you say "Add an image to your project directory and rename it to test-upload.jpg" but actually the js code expects test-image.jpg. Anyway, thanks for this, it helped me understand LocalStack.

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Nippontradamus •

Hey @Joseph!

I am unable to see my bucket in the localhost:8055 page, however, I can see the bucket in the localhost:4572 page.

Great article though! I enjoyed reading it and was helpful in understanding the process. Keep it up

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Sergio Bilello • • Edited

@Joseph great job but I was wondering why we get a warning. Do you have the same message in the log?
I have also to refresh the browse localhost:8055 2-3 times to see all the resources created.
Do you have the same problem?

localstack_demo_orig | 2019-06-26T17:57:57:DEBUG:localstack.services.s3.s3_listener: Found no <LastModified>(.*)</LastModified> inside response_content: list index out of range
localstack_demo_orig | WARNING: Unable to get details for bucket: [Errno 1] Operation not permitted: '/tmp/cache.fbd52520e8bfc4938a74ed8204e80533.json'
localstack_demo_orig | 2019-06-26T17:57:59:DEBUG:localstack.services.s3.s3_listener: Found no <LastModified>(.*)</LastModified> inside response_content: list index out of range
localstack_demo_orig | 2019-06-26T17:58:04:INFO:werkzeug: 127.0.0.1 - - [26/Jun/2019 17:58:04] "GET / HTTP/1.1" 200 -
localstack_demo_orig | 2019-06-26T17:58:04:DEBUG:localstack.services.s3.s3_listener: Found no <LastModified>(.*)</LastModified> inside response_content: list index out of
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Joseph Thomas •

Hi Sergio,

I'm not sure why this is coming up - I don't remember seeing messages like this. It might be that your /tmp/ directory is not readable or writeable? This might be something to ask on Stack Overflow or on the Github page for localstack. Sorry I can't be of help!

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Juliette •

Thank you for this Joseph!!

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Moji • • Edited

hi friend, thanks for your Great article
i have also problem with accessing the ui of localStack with both Docker images (on post and localstack-latest) 2022-10-23
but i run my container with
localstack/localstack-full:0.11.6
and it works
thank you

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chan_austria777 profile image
chan 🤖 •

For anyone who's encountered an error when using the latest module @aws-sdk/client-s3, use forcePathStyle instead of s3ForcePathStyle.

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Ahmed Chouihi •

I have added also list objects function for anyone need to use it :

In aws.js
I have added this :

var bucketParams = {
Bucket : 'demo-bucket',
};
const listObjects = () =>{
s3client.listObjects(bucketParams, function(err, data) {
if (err) {
console.log("Error", err);
} else {
console.log("Success", data);
}
});
}

module.exports = listObjects

I have added other file named list-objects.js

const fs = require('fs')
const path = require('path')
const listObjects = require('./aws')

listObjects()

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Yisus •

Awesome, very well explained. It has definitely helped me with the localstack setup. Thanks!

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elmentecato • • Edited

I had to add
s3BucketEndpoint: true
to the AWS.S3({ }) config in aws.js to make it work.

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abduelwhidi2 profile image
abduelwhidi2 •

Thanks for this article.
I am having issues running lambda functions on localstack. Did you guys try it out?
I started my aws service and seems working using the command.

docker run -e LAMBDA_EXECUTOR=docker -p 4574:4574 -e SERVICES=lambda -p 8080:8080 localstack/localstack &

I tried to upload a function, I have security issues

aws --endpoint-url=localhost:4574 lambda create-function --function-name=f1 --runtime=python2.7 --role=default --handler=lambda.handler --zip-file fileb://lambda.zip

But even the simple list does not work. I got:

Could not connect to the endpoint URL: "localhost:4574/2015-03-31/functions"

Thx
Abdu

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Dean •

Great article, thank you! I think there is one small typo. You have a reference to http://localhost:8050 in the opening of your Docker Config section. Should it be http://localhost:8055?

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Joseph Thomas •

Just fixed it, thanks for letting me know!

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Tammy Lee •

This was a great walkthrough! Thank you so much, Joseph!
I'd never heard of Localstack before now and did everything probably the slowest and most manual way possible before.

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JavaTec •

Hi Joseph, Great article, thank you. By any chance do you have a working example for Kinesis using localstack inside Docker?

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Joseph Thomas •

Unfortunately, no - my experience with AWS doesn't go much further than S3, RDS & Lambdas.

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JavaTec •

thank you for the reply!

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Christophe •

Great article Joseph! Thank you... I think you have a natural gift for explaining things :-) ... I am looking forward to reading the next one.

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Joseph Thomas •

Thank you! 😊

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Jef LeCompte •

Love using localstack. Nice write up!

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bugkerb •

Thanks Joseph! It's very nice article.

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IsacNetero •

Thanks dude this was very helpful keep up the good work

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Victor Duarte •

How do you handle hot reloading?
I was hoping I could have a fast way to iterate over local changes to my lambda functions, but I couldn't find a way to do so.

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aquan0 •

When I go to localhost:8085, but I don't understand what is wrong that makes it unable to display the dashboard
May you help me?

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Matteo Gioioso •

Have you manage to make it work with SAM or even cloudformation?

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Ahmed Chouihi •

Thanks very useful tutorial

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Tien Pham •

Thanks Joseph!