generate.go

/*
Copyright 2014 Google Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package kubectl

import (
	"fmt"
	"strings"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
	"github.com/golang/glog"
	"github.com/spf13/cobra"
)

// GeneratorParam is a parameter for a generator
// TODO: facilitate structured json generator input schemes
type GeneratorParam struct {
	Name     string
	Required bool
}

// Generator is an interface for things that can generate API objects from input parameters.
type Generator interface {
	// Generate creates an API object given a set of parameters
	Generate(params map[string]string) (runtime.Object, error)
	// ParamNames returns the list of parameters that this generator uses
	ParamNames() []GeneratorParam
}

// Generators is a global list of known generators.
// TODO: Dynamically create this from a list of template files?
var Generators map[string]Generator = map[string]Generator{
	"run-container/v1": BasicReplicationController{},
	"service/v1":       ServiceGenerator{},
}

// ValidateParams ensures that all required params are present in the params map
func ValidateParams(paramSpec []GeneratorParam, params map[string]string) error {
	for ix := range paramSpec {
		if paramSpec[ix].Required {
			value, found := params[paramSpec[ix].Name]
			if !found || len(value) == 0 {
				return fmt.Errorf("Parameter: %s is required", paramSpec[ix].Name)
			}
		}
	}
	return nil
}

// MakeParams is a utility that creates generator parameters from a command line
func MakeParams(cmd *cobra.Command, params []GeneratorParam) map[string]string {
	result := map[string]string{}
	for ix := range params {
		f := cmd.Flags().Lookup(params[ix].Name)
		if f != nil {
			result[params[ix].Name] = f.Value.String()
		}
	}
	return result
}

func MakeLabels(labels map[string]string) string {
	out := []string{}
	for key, value := range labels {
		out = append(out, fmt.Sprintf("%s=%s", key, value))
	}
	return strings.Join(out, ",")
}

// ParseLabels turns a string representation of a label set into a map[string]string
func ParseLabels(labelString string) map[string]string {
	if len(labelString) == 0 {
		return nil
	}
	labels := map[string]string{}
	labelSpecs := strings.Split(labelString, ",")
	for ix := range labelSpecs {
		labelSpec := strings.Split(labelSpecs[ix], "=")
		if len(labelSpec) != 2 {
			glog.Errorf("unexpected label spec: %s", labelSpecs[ix])
			continue
		}
		labels[labelSpec[0]] = labelSpec[1]
	}
	return labels
}