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factory.go
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factory.go
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package factory
import (
"fmt"
"github.com/RackHD/ipam/interfaces"
)
// factory is a storage map for resource creator functions registered via init.
var factory = make(map[string]interfaces.ResourceCreator)
// Register associates the resource identifier with a resource creator function.
func Register(resource string, creator interfaces.ResourceCreator) {
factory[resource] = creator
}
// Request finds a resource creator function by the resource identifier and calls
// the creator returning the result. The resulting resource may be a default version
// if the reqeusted version is not present.
func Request(resource string, version string) (interfaces.Resource, error) {
if creator, ok := factory[resource]; ok {
return creator(version)
}
return nil, fmt.Errorf("Request: Unable to locate resource %s.", resource)
}
// Require finds a resource creator function by the resource identifier and verifies
// the created resource matches the requested version. If not, an error will be
// returned.
func Require(resource string, version string) (interfaces.Resource, error) {
provided, err := Request(resource, version)
if err != nil {
return nil, err
}
if provided.Version() != version {
return nil, fmt.Errorf("Require: Unable to locate resource %s, version %s.", resource, version)
}
return provided, nil
}