Add a CMD instruction to a dockerfile

Adds a CMD instruction to provide defaults for an executing container. These defaults can be executable programs or commands to be executed when the container starts.

Usage

dfi_cmd(dockerfile, command)

Arguments

dockerfile

A dockerfile object

command

Command to run (character vector or string)

Value

An updated dockerfile object with the CMD instruction added

Details

The function automatically converts the command to JSON array format, which is the recommended approach for better signal handling. Only one CMD instruction is effective in a Dockerfile; if multiple are specified, only the last one will take effect.

See also

dfi_entrypoint() for defining the main executable of the container, dfi_run() for executing commands during the build, & Official Docker CMD documentation

Other dockerfile instruction functions: dfi_add(), dfi_arg(), dfi_copy(), dfi_entrypoint(), dfi_env(), dfi_expose(), dfi_from(), dfi_healthcheck(), dfi_label(), dfi_maintainer(), dfi_onbuild(), dfi_run(), dfi_shell(), dfi_stopsignal(), dfi_user(), dfi_volume(), dfi_workdir()

Examples

# Simple command
df <- dockerfile() |>
  dfi_from("rocker/r-ver:4.4.0") |>
  dfi_copy("script.R", "/app/script.R") |>
  dfi_cmd("Rscript /app/script.R")

# Array format (recommended)
df <- dockerfile() |>
  dfi_from("rocker/r-ver:4.4.0") |>
  dfi_cmd(c("R", "--no-save"))