Deploying a Flutter application to production is mostly easy - simply make a build and upload it to the store. However, for web applications built with Flutter, we need to upload our build to the web server.

To build a web application, simply run:

flutter build web --base-href "/webapp/" --release

But what if we would like to deploy it to our server right away? To do this, we can use a great Docker image instrumentisto/flutter, which is basically a ready-to-use Flutter development environment packed into a Docker image.

One of the simplest ways is to run our pipeline directly on the web server. The prerequisite is that we have Docker installed there.

So to build a Flutter app, use this code in the pipeline:

docker run --rm -v ./:/app -w /app instrumentisto/flutter flutter build web  --release

This would deploy the web application into the ./build/webapp folder. Now you can copy it to your web server like this:

 rsync -r --delete build/web/*  /my/sebserver/location

and here is the full pipeline as an example:

pipelines:
  default:
    - step:
        name: build staging web app
        runs-on:
          - 'self.hosted'
          - 'linux.shell'
        script:
          - docker run --rm -v ./:/app -w /app instrumentisto/flutter flutter build web  --release 
          - rsync -r --delete ./build/web/*  /opt/webapp/