docker/convert

docker/convert turns one or more docker run commands into a Docker Compose document. Commands are parsed as text and never executed, so shell substitutions such as $(...) are copied through literally.

Module

go.getarcane.app/docker/convert

Source

github.com/getarcaneapp/kit/tree/main/docker/convert

Reference

pkg.go.dev

go get go.getarcane.app/docker/convert@latest

Convert in one call

import (
  "go.getarcane.app/docker/convert"
  converttypes "go.getarcane.app/docker/convert/types"
)

result, err := convert.Convert(
  `docker run -d --name web -p 8080:80 -v data:/usr/share/nginx/html nginx:1.27`,
  converttypes.Options{},
)
if err != nil {
  return err
}

fmt.Println(string(result.YAML))

Result contains:

Field	Description
YAML	The rendered Compose file
Project	The same document as a parsed compose-go *types.Project
Services	Name and image of each generated service
EnvFile	.env contents collected from every -e KEY=VALUE flag, or nil when there are none
Warnings	Flags that could not be represented in Compose

Set Options.ExistingComposeYAML to merge the new services into an existing file, and Options.RenderWarnings to add warnings as # comments at the top of the YAML.

Step by step

Convert is a pipeline of three public steps you can call yourself:

cmds, err := convert.Parse(input, converttypes.ParseOptions{})          // []RunCommand
doc, err := convert.Build(cmds, converttypes.Options{})                 // *Document
yaml, err := convert.Marshal(doc, converttypes.MarshalOptions{})        // []byte

This lets you inspect or change the intermediate RunCommand (image, name, command, entrypoint, and flags) or Document (services, networks, volumes, and warnings).

Errors

Errors wrap one of two sentinels:

switch {
case errors.Is(err, converttypes.ErrParse):
  // The input is not a valid docker run command, e.g. no image.
case errors.Is(err, converttypes.ErrConversion):
  // Parsed, but could not be represented as Compose.
}