Bash function for creating `fly exec` scripts from concourse task config files

mkexec.sh

mkexec() {
  if [[ $# != 1 ]]; then
    echo "Usage: ${FUNCNAME[0]} </path/to/task/config.yml>"
    return 1
  fi

  task_config=$1

  if ! [[ -f "${task_config}" ]]; then
    echo "Could not find file ${task_config}"
    return 1
  fi

  task_config_abs_path="$(cd "$(dirname "${task_config}")" && pwd)/$(basename "${task_config}")"
  task_config_json="$(yj -yj < "${task_config_abs_path}")"
  task_name="$(basename "$(dirname "${task_config_abs_path}")")"

  params=""
  for param in $(echo "${task_config_json}" | jq -r '.params // [] | keys | .[]'); do
    params+="${param}='' \\"$'\n'
  done

  inputs=""
  for input in $(echo "${task_config_json}" | jq -r '.inputs // [] | .[].name'); do
    if [[ -d "${HOME}/workspace/${input}" ]]; then
      inputs+="-i ${input}=\"${HOME}/workspace/${input}\" \\"$'\n'
    else
      inputs+="-i ${input}=\"\" \\"$'\n'
    fi
  done

  outputs=""
  for output in $(echo "${task_config_json}" | jq -r '.outputs // [] | .[].name'); do
    outputs+="-o ${output}=\"\${outputs_dir}/${output}\" \\"$'\n'
  done

  outputs_dir="$(mktemp -d)"
  rmdir "${outputs_dir}"

  fly_exec_command=$(cat <<-EOF
${params}
fly -t <YOUR-TARGET-HERE> e \\
  -c "${task_config_abs_path}" \\
  ${inputs}
  ${outputs}
#  --include-ignored
#  --privileged
EOF
)

  exec_script="exec-${task_name}"
  cat >"${exec_script}" <<-EOF
#!/usr/bin/env bash

set -euo pipefail

outputs_dir="${outputs_dir}"
rm -rf "\$outputs_dir"
mkdir -p "\$outputs_dir"

$(echo "${fly_exec_command% \\}" | grep -v '^$' | sed 's/^-/  -/')
EOF

  chmod +x "${exec_script}"
}