tiny-forge/internal/docker/network.go

package docker

import (
	"context"
	"fmt"

	"github.com/moby/moby/api/types/network"
	"github.com/moby/moby/client"
)

// EnsureNetwork creates a Docker network with the given name if it does not
// already exist. It returns the network ID in all cases.
func (c *Client) EnsureNetwork(ctx context.Context, networkName string) (string, error) {
	// Check if the network already exists.
	filterArgs := make(client.Filters).Add("name", networkName)

	listResult, err := c.api.NetworkList(ctx, client.NetworkListOptions{
		Filters: filterArgs,
	})
	if err != nil {
		return "", fmt.Errorf("list networks for %s: %w", networkName, err)
	}

	// NetworkList with a name filter may return partial matches, so check exact name.
	for _, n := range listResult.Items {
		if n.Name == networkName {
			return n.ID, nil
		}
	}

	// Create the network.
	resp, err := c.api.NetworkCreate(ctx, networkName, client.NetworkCreateOptions{
		Driver: "bridge",
		Labels: map[string]string{
			LabelManaged: "true",
		},
	})
	if err != nil {
		return "", fmt.Errorf("create network %s: %w", networkName, err)
	}

	return resp.ID, nil
}

// ConnectNetwork attaches a container to an existing network.
func (c *Client) ConnectNetwork(ctx context.Context, networkID string, containerID string) error {
	_, err := c.api.NetworkConnect(ctx, networkID, client.NetworkConnectOptions{
		Container:      containerID,
		EndpointConfig: &network.EndpointSettings{},
	})
	if err != nil {
		return fmt.Errorf("connect container %s to network %s: %w", containerID, networkID, err)
	}
	return nil
}