docker/compat

docker/compat makes newer Docker features depend on the API version the daemon actually supports, so in-process API callers work against older engines and Podman. The Docker CLI applies these workarounds for you. Code that calls the API directly has to apply them itself.

Module

go.getarcane.app/docker/compat

Source

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

Reference

pkg.go.dev

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

The easy way: wrap the client

import "go.getarcane.app/docker/compat"

api := compat.WrapDockerAPIClientForInspectCompatibility(cli)
// api.ContainerCreate, ContainerInspect, NetworkInspect, and NetworkList now
// apply the compatibility shims transparently.

Container create

ContainerCreateWithCompatibility detects the daemon’s API version and adjusts the request:

• Before API 1.44, daemons don’t reliably accept multiple EndpointsConfig entries. The container is created on its primary network, and the other networks are attached with NetworkConnect before it returns. If an attachment fails, the half-connected container is removed, even if ctx was canceled.
• Before API 1.44, per-network MAC addresses are dropped from the endpoint settings.

res, err := compat.ContainerCreateWithCompatibility(ctx, cli, client.ContainerCreateOptions{
  Config:           cfg,
  HostConfig:       hostCfg,
  NetworkingConfig: netCfg,
  Name:             "web",
})

For more control, call the steps yourself:

version := compat.DetectDockerAPIVersion(ctx, cli)
opts, withheld := compat.PrepareContainerCreateOptionsForDockerAPI(opts, version)
// ... create the container ...
err = compat.ConnectContainerExtraNetworksForDockerAPI(ctx, cli, id, withheld)

Inspect and list

Newer Moby address types reject CIDR suffixes that some daemons include. ContainerInspectWithCompatibility, NetworkInspectWithCompatibility, and NetworkListWithCompatibility retry a failed typed decode against the raw JSON with those suffixes removed.

Recreating on Podman

Podman with cgroup v2 rejects some HostConfig fields that Docker accepts, such as MemorySwappiness. Before you recreate a container:

hostCfg, changed, engine, err := compat.PrepareRecreateHostConfigForEngine(ctx, cli, inspect.HostConfig)
if changed {
  log.Info("sanitized host config", "engine", engine.Name, "cgroup", engine.CgroupVersion)
}

Version helpers

Symbol	Description
DetectDockerAPIVersion	The client’s negotiated version, or the daemon’s reported version
IsDockerAPIVersionAtLeast(current, min)	Numeric comparison of dotted versions such as 1.43 and 1.44.1
NetworkScopedMacAddressMinAPIVersion	"1.44"
MultiEndpointContainerCreateMinAPIVersion	"1.44"