docker/swarmkit

package config

import (
    "context"
    "fmt"

    "github.com/moby/swarmkit/v2/api"
)

func getConfig(ctx context.Context, c api.ControlClient, input string) (*api.Config, error) {
    // not sure what it is, match by name or id prefix
    resp, err := c.ListConfigs(ctx,
        &api.ListConfigsRequest{
            Filters: &api.ListConfigsRequest_Filters{
                Names:      []string{input},
                IDPrefixes: []string{input},
            },
        },
    )
    if err != nil {
        return nil, err
    }

    switch len(resp.Configs) {
    case 0:
        return nil, fmt.Errorf("config %s not found", input)
    case 1:
        return resp.Configs[0], nil
    default:
        // ok, multiple matches.  Prefer exact ID over exact name.  If no exact matches, return an error
        for _, s := range resp.Configs {
            if s.ID == input {
                return s, nil
            }
        }
        for _, s := range resp.Configs {
            if s.Spec.Annotations.Name == input {
                return s, nil
            }
        }
        return nil, fmt.Errorf("config %s is ambiguous (%d matches found)", input, len(resp.Configs))
    }
}