There's other more interesting stuff which you would get with longer running instances like Containe

There's other more interesting stuff which you would get with longer running instances like Containers like database connection pooling and being close to origin for many calls back and forth, which CF has aimed to solve in Workers direct with different ways like Hyperdrive and Smart Placement

Tim•9/13/25, 8:29 AM

Indeed. We would have websockets and I was thinking of taking advantage of both go's concurrency and websocket connections where speed could be beneficial if there is a minor gain.

To that end, how does the WASM go compare to the worker operating directly out of curiosity - if someone has done any benchmarks.

Steps•9/14/25, 4:33 PM

The docs on https://developers.cloudflare.com/containers/ are outdated.

The sample JavaScript doesn't compile and the TOML has with instancesinstances a deprecated property.

I try to find out how a minimalistic index.js & TOML must look like to fire up my Docker contaner

CChaika There's other more interesting stuff which you would get with longer running ins...

Steps•9/14/25, 4:36 PM

I guess containers are also interesting where there is a lack of support in JavaScript.
I'm working on a worker that uploads to an external S3 - AI attempts to generate complicated stuff to do the signing.

Steps•9/14/25, 4:39 PM

The new samples are all index.ts (typescript) and jsonc instead of TOML. I want it easier.

Steps•9/14/25, 4:45 PM

The TOML is invalid as it lacks a compatibility date

udidu•9/15/25, 12:12 PM

The image_vars doesn't seems to work.
When I try to use it, the Dockerfile can't see the values of the build args.

For examle, this is how I setup my container inside wrangler.jsonc

        {
            "max_instances": 3,
            "name": "my-services-container",
            "class_name": "MyServicesContainer",
            "image": "./my-services-container/Dockerfile",
            "instance_type": "standard",
            "image_vars": {
                "NPM_TOKEN": "MY_NPM_TOKEN_SECRET"
            }
        }

        {
            "max_instances": 3,
            "name": "my-services-container",
            "class_name": "MyServicesContainer",
            "image": "./my-services-container/Dockerfile",
            "instance_type": "standard",
            "image_vars": {
                "NPM_TOKEN": "MY_NPM_TOKEN_SECRET"
            }
        }

In my Dockerfile I use

ARG NPM_TOKEN

# Install dependencies first
RUN npm install

ARG NPM_TOKEN

# Install dependencies first
RUN npm install

The wrangler deploy fails on the npm install part: unauthenticated: User cannot be authenticated with the token provided.

However, when I set the token value manually inside my Dockerfile it works:

ARG NPM_TOKEN=MY_NPM_TOKEN_SECRET

# Install dependencies first
RUN npm install

ARG NPM_TOKEN=MY_NPM_TOKEN_SECRET

# Install dependencies first
RUN npm install

Uudidu The image_vars doesn't seems to work. When I try to use it, the Dockerfile can't...

darkpool•9/15/25, 11:37 PM

try

ARG NPM_TOKEN
ENV NPM_TOKEN=$NPM_TOKEN

ARG NPM_TOKEN
ENV NPM_TOKEN=$NPM_TOKEN

CodingCoop | Co-Founder Nullshot•9/16/25, 5:18 AM

Congrats on container feature + release team.

Is it possible to reach out to cloudflare to increase limits on containers when they are reached?

Also where is the best place to report feature requests - ideally we can set container type via startup param if possible allowing dynamic sizing based on demand versus configuring it as an env var / binding.

Ddarkpool try ``` ARG NPM_TOKEN ENV NPM_TOKEN=$NPM_TOKEN ```

udidu•9/16/25, 7:55 AM

Not working... :/ It looks like the build args not passed to the Docker build...

Ankan Saha•9/16/25, 2:11 PM

I found a issue in the container project

Uudidu Not working... :/ It looks like the build args not passed to the Docker build...

kian•9/16/25, 2:51 PM

What version of Wrangler are you using?

Kkian What version of Wrangler are you using?

udidu•9/16/25, 2:51 PM

4.33.1

kian•9/16/25, 2:52 PM

"image_vars": {
  "FOO": "BAR"
}

"image_vars": {
  "FOO": "BAR"
}

ARG FOO
RUN echo $FOO

ARG FOO
RUN echo $FOO

=> [build 3/8] RUN echo BAR

=> [build 3/8] RUN echo BAR

kian•9/16/25, 2:53 PM

It seems to work fine for me

udidu•9/16/25, 2:56 PM

Wow, it was my mistake, I had the "containers" set twice on my wrangler.jsonc (one for production env) and I forgot to set the image_vars on the production containers...
Anyway now it works, sorry

Is there any way I can pass the image_vars from env? since I don't want to push to my repo the secrets for the build command

kian•9/16/25, 3:37 PM

Not currently but I think secret mounts (https://docs.docker.com/build/building/secrets/#secret-mounts) would be the best method here - we don't currently expose a way to use those either.

kian•9/16/25, 3:37 PM

I'll take it back to the team & see what we can do.

Kkian Not currently but I think secret mounts (<https://docs.docker.com/build/building...

udidu•9/16/25, 4:55 PM

I've ended up changing the wrangler.jsonc file inside my github action where I replace the env params placeholders inside the image_vars with secrets from Github :/
I'm not proud of it, but it works

Steps•9/16/25, 5:02 PM

I'm puzzled why nobody fixes the broken getting started docs. :/

kian•9/16/25, 5:34 PM

There’s a docs rework already in flight that fixes up & reorganises the whole /containers/ area

Steps•9/16/25, 7:37 PM

Ah, that’s good to know.

Steps•9/16/25, 7:37 PM

I really want to give containers a shot, but can’t find a working simple sample

julian7797•9/16/25, 8:28 PM

When running locally, I'm not seeing any of my container logs, is there a way to view them?

julian7797•9/16/25, 8:29 PM

Also, my container isn't able to access local databases I'm running, is there a way to enable this with wrangler?

SSteps I really want to give containers a shot, but can’t find a working simple sample

kian•9/16/25, 8:47 PM

https://github.com/cloudflare/templates/tree/main/containers-template is probably the most simple example right now

Steps•9/16/25, 9:01 PM

Yeah, I saw that, but TypeScript and JSONC are more complex than JavaScript and wrangler.TOML

There is a sample in the docs, but it's outdated and non-functional.

Steps•9/16/25, 9:02 PM

JSONC is barely human readable. TOML is way cleaner and easier to grasp.

TypeScript requires tsconfig.json and other stuff.
I'd like a minimal JavaScript standalone file that does the forwarding to the container.

Steps•9/16/25, 9:04 PM

I understand the TS move, but why would you migrate to jsonc?

James•9/16/25, 9:21 PM

fwiw I entirely agree with you and think cf pushing json(c) as config by default was a mistake. I was outspoken against this from the start, but they're all in on it now sadly, despite it being imo measurably worse than toml in so many ways.

James•9/16/25, 9:23 PM

other than that though, I would definitely grab that template from the repo kian linked. It's a good starter, and you can always convert the jsonc to toml (even though I agree you shouldn't have to). I still use toml in all of my projects

(and cloudflare does for lots too: https://github.com/cloudflare/cloudflare-docs/blob/production/wrangler.toml)

julian7797•9/16/25, 9:30 PM

Need a way to access local host ports when running in dev

Jjulian7797 Need a way to access local host ports when running in dev

kian•9/16/25, 9:32 PM

Use

host.docker.internal

host.docker.internal

localhost

localhost

to a container is just itself rather than your host machine.

julian7797•9/16/25, 9:32 PM

thx

julian7797•9/16/25, 9:32 PM

Skill issue on my part

julian7797•9/16/25, 9:32 PM

appreciate the assist

kian•9/16/25, 9:32 PM

I think there is some Docker network modes where you can use

localhost

localhost

but for the default

host.docker.internal

host.docker.internal

is the way

julian7797•9/16/25, 9:34 PM

Cool, also would love to see Hyperdrive support inside the containers

julian7797•9/16/25, 9:34 PM

I think it might already be in a feature request

kian•9/16/25, 9:39 PM

It's on our radar but no ETA - you can follow this GitHub issue for updates: https://github.com/cloudflare/workers-sdk/issues/10320

GitHub

feature: connect to hyperdrive from inside a container · Issue #10...

What versions & operating system are you using? System: OS: macOS 15.5 CPU: (8) arm64 Apple M3 Memory: 120.78 MB / 16.00 GB Shell: 5.9 - /bin/zsh Binaries: Node: 24.2.0 - /opt/homebrew/bin/node...

julian7797•9/16/25, 11:53 PM

Probably missing a config option or something but i have zero logs showing up for my container, and its definitely getting hit bc i see memory, cpu, etc increasing for requests

Jjulian7797 Probably missing a config option or something but i have zero logs showing up fo...

julian7797•9/17/25, 12:00 AM

deleted and recreated, logs showing up now

TangoBee•9/17/25, 12:13 PM

Hi,
I'm using containers locally with npx wrangler dev, but I don't see any logs that I have added in my container code in the terminal.

China•9/17/25, 6:08 PM

Hi everyone,

I'm using Wrangler to deploy a project that's currently configured with a container. The issue is that even when there are no code changes in the container, every time I run wrangler deploy, it rebuilds the container image and pushes it, which takes a lot of time and resources.

Does anyone know if it's possible to use wrangler deploy to update the worker without rebuilding and pushing the container every time?

julian7797•9/17/25, 8:26 PM

Are custom container instance types still up to date in docs? Tried setting according to here: https://developers.cloudflare.com/workers/wrangler/configuration/#custom-instance-types but getting a validate input error while deploying (have an enterprise account)

Cloudflare Docs

Configuration

Use a configuration file to customize the development and deployment setup for your Worker project and other Developer Platform products.

bro14•9/18/25, 1:08 PM

hello does anyone knows how to fix this X [ERROR] You don't have 'containers:write' in your list of scopes i've already added permission on my API TOKEN to edit containers(i don't think there's write option)

updating to latest wrangler works

blyedev•9/19/25, 2:39 AM

Hi everyone quick question. Would it be possible to use hyperdrive with containers?

zerozerozeroone•9/19/25, 3:37 AM

Do or can containers run in a single location?
If containers are idle are they stopped?
Are idle containers that still run but aren’t serving anything still consuming cpu resources?

Bblyedev Hi everyone quick question. Would it be possible to use hyperdrive with containe...

ChaikaOP•9/19/25, 3:44 AM

it's on the roadmap but not yet containers-beta

blyedev•9/19/25, 3:45 AM

It really is great to see that everything I ever need consistently is one the roadmap haha

ChaikaOP•9/19/25, 3:45 AM

soon^tm

There's other more interesting stuff which you would get with longer running instances like Containe

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