Creating a buildx fails when using matrix strategy on self hosted runners

Behavior

When creating a builder instance using GitHub’s matrix strategy to build multiple images in parallel the Creating a new builder instance action step fails with an error that looks related to the naming strategy used to create new builders:

📣 Buildx version: 0.4.2
🔨 Creating a new builder instance
  /usr/bin/docker buildx create --name builder-build-linux-images-2 --driver docker-container --driver-opt env.http_proxy=***** --driver-opt env.https_proxy=***** --driver-opt image=******* --buildkitd-flags --allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host --use
  existing instance for builder-build-linux-images-2 but no append mode, specify --node to make changes for existing instances
  Error: The process '/usr/bin/docker' failed with exit code 1

Probably related to this line?

Steps to reproduce this issue

1. Set a workflow with whichever trigger you want
2. Add a setup-buildx-action to the workflow
3. Parallelize your job with the matrix strategy
4. Run on multiple self-hosted runners on the same server

Expected behavior

The action should assign unique names for the builders

Actual behavior

If the builder is being instantiated with the matrix strategy some of the builders will have the same name

Configuration

• Repository URL (if public): Private repo
• Build URL (if public): Private repo

name: Main-CI

on:
  push:
    branches: [main]
jobs:
  build-linux-images:
    runs-on: [self-hosted, linux]
    strategy:
      matrix:
        include:
          - package: package1
            directory: docker/linux/package1
          - package: package2
            directory: docker/linux/package2
          - package: package3
            directory: docker/linux/package3
          - package: package4
            directory: docker/linux/package4
    steps:
      -
        uses: actions/checkout@v2
      -
        name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@v1

[malkam03]

This works perfect! Thank you @crazy-max 😄

[crazy-max]

@malkam03 Ok can you try again with uses: docker/setup-buildx-action@master?