How to use chromedp with docker-headless-shell

[invasionofsmallcubes]

What versions are you running?

[[constraint]]
  name = "github.com/chromedp/chromedp"
  version = "0.3.0"

What did you do? Include clear steps.

Hi guys, I tried to look something using google but I couldn't find anything related to it.
If I use docker-headless-shell, how do I use chromedp to connect remotely to docker, go to a page and generate a pdf?
I mean, I understood I should use RemoteAllocatorbut it would be nice to have an example if possible.

It's basically help wanted. Thank you if you can answer me.

[mvdan]

Hi,

You don't need to use RemoteAllocator. Usually, the simplest solution is to run your Go binary from within the docker image with headless-shell, and then let chromedp execute headless-shell.

I'll add this to the FAQ.

[vianhanif]

@mvdan would you please give a small example on this in setting up a dockerized golang app with headless-shell ? Thanks

[lifegit]

@vianhanif

Excuse me, have you solved it?

[ZekeLu]

With ExecAllocator

There are two ways to run your Go binary from within the docker image.

1. build an image based on chromedp/headless-shell

Here is an example Dockerfile:

# =============== build stage ===============
FROM golang:1.16.5-buster AS build
WORKDIR /app

COPY go.* ./
RUN go mod download -x all

COPY . ./
# ldflags:
#  -s: disable symbol table
#  -w: disable DWARF generation
# run `go tool link -help` to get the full list of ldflags
RUN go build -ldflags "-s -w" -o the-excellent-app -v path/to/main.go

# =============== final stage ===============
FROM chromedp/headless-shell:93.0.4535.3 AS final

WORKDIR /app
COPY --from=build /app/the-excellent-app ./
ENTRYPOINT ["/app/the-excellent-app", "-other", "flags"]

Build it and then run this image.

2. use volume to run your app without creating a new image (useful for temporary testing)

Build you app on the host computer first, then run this command (make sure your pre-compiled app is in the current working directory):

docker run \
    --rm \
    --volume=$PWD:/chromedp \
    --entrypoint=/chromedp/the-excellent-app \
    --env=PATH=/headless-shell \
    chromedp/headless-shell:93.0.4535.3

With RemoteAllocator

The PR #817 makes it easy to use a standalone chromedp/headless-shell container with RemoteAllocator. Check #817 (comment) for a full example.

[lifegit]

@ZekeLu
Thank！

Do you recommend option 1 or option 2 ？

1: docker images size 260mb, is huge, I'm worried.

2: It's a lot smaller, but need to install chrome on the host in advance.

[ZekeLu]

I would choose option 1, because it will make it easy to deploy the app.

And in my opinion, 260mb is not big (and far from huge 😄 ). If you install chrome on the host, it will take up remarkable spaces too (I don't know how much it will take, but the size of chrome-linux.zip for the latest build of Chromium is 140+MB).

[lifegit]

thank！
I think a good go docker image is only a few mb (3mb-5mb), because it doesn't have a runtime。

Although each version needs 260mb, But it's very convenient ! so, take your advice , option 1 !