Ensuring Buildkite pipeline steps run on the same agent, using a dynamic pipeline generator script

pipeline.sh

#!/bin/bash

# Outputs a pipeline that targets agents that have the same 'name' meta-data
# value as the step that does the pipeline upload. This means that all the
# steps will run on the same agent machine, assuming that the 'name' meta-data
# value is unique to each agent.
#
# Each agent needs to be configured with meta-data like so:
#
# meta-data="name=<unique-name>"
#
# To use, save this file as .buildkite/pipeline.sh, chmod +x, and then set your
# first pipeline step to run this and pipe it into pipeline upload:
#
# .buildkite/pipeline.sh | buildkite-agent pipeline upload
#

name=$(buildkite-agent meta-data get name)

cat << EOF
steps:
  - command: step-1.sh
    name: "First step"
    agents:
      name: "$name"

  - command: step-2.sh
    name: "Second step"
    agents:
      name: "$name"

  - command: step-3.sh
    name: "Third step"
    agents:
      name: "$name"
EOF