forked from openshift/origin
/
template.go
166 lines (151 loc) · 5.64 KB
/
template.go
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package template
import (
"fmt"
"regexp"
"strings"
kapi "github.com/GoogleCloudPlatform/kubernetes/pkg/api"
"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
"github.com/golang/glog"
config "github.com/openshift/origin/pkg/config/api"
deployapi "github.com/openshift/origin/pkg/deploy/api"
"github.com/openshift/origin/pkg/template/api"
. "github.com/openshift/origin/pkg/template/generator"
)
var parameterExp = regexp.MustCompile(`\$\{([a-zA-Z0-9\_]+)\}`)
// TemplateProcessor transforms Template objects into Config objects.
type TemplateProcessor struct {
Generators map[string]Generator
}
// NewTemplateProcessor creates new TemplateProcessor and initializes
// its set of generators.
func NewTemplateProcessor(generators map[string]Generator) *TemplateProcessor {
return &TemplateProcessor{Generators: generators}
}
// Process transforms Template object into Config object. It generates
// Parameter values using the defined set of generators first, and then it
// substitutes all Parameter expression occurances with their corresponding
// values (currently in the containers' Environment variables only).
func (p *TemplateProcessor) Process(template *api.Template) (*config.Config, error) {
if err := p.GenerateParameterValues(template); err != nil {
return nil, err
}
if err := p.SubstituteParameters(template); err != nil {
return nil, err
}
config := &config.Config{
Name: template.Name,
Description: template.Description,
Items: template.Items,
}
config.ID = template.ID
config.Kind = "Config"
config.CreationTimestamp = util.Now()
return config, nil
}
// AddParameter adds new custom parameter to the Template. It overrides
// the existing parameter, if already defined.
func (p *TemplateProcessor) AddParameter(t *api.Template, param api.Parameter) {
if existing := p.GetParameterByName(t, param.Name); existing != nil {
*existing = param
} else {
t.Parameters = append(t.Parameters, param)
}
}
// GetParameterByName searches for a Parameter in the Template
// based on it's name.
func (p *TemplateProcessor) GetParameterByName(t *api.Template, name string) *api.Parameter {
for i, param := range t.Parameters {
if param.Name == name {
return &(t.Parameters[i])
}
}
return nil
}
// SubstituteParameters loops over all Environment variables defined for
// all ReplicationController and Pod containers and substitutes all
// Parameter expression occurances with their corresponding values.
//
// Example of Parameter expression:
// - ${PARAMETER_NAME}
//
// TODO: Implement substitution for more types and fields.
func (p *TemplateProcessor) SubstituteParameters(t *api.Template) error {
// Make searching for given parameter name/value more effective
paramMap := make(map[string]string, len(t.Parameters))
for _, param := range t.Parameters {
paramMap[param.Name] = param.Value
}
for i, item := range t.Items {
switch obj := item.Object.(type) {
case *kapi.ReplicationController:
p.substituteParametersInManifest(&obj.DesiredState.PodTemplate.DesiredState.Manifest, paramMap)
t.Items[i] = runtime.EmbeddedObject{Object: obj}
case *kapi.Pod:
p.substituteParametersInManifest(&obj.DesiredState.Manifest, paramMap)
t.Items[i] = runtime.EmbeddedObject{Object: obj}
case *deployapi.Deployment:
p.substituteParametersInManifest(&obj.ControllerTemplate.PodTemplate.DesiredState.Manifest, paramMap)
t.Items[i] = runtime.EmbeddedObject{Object: obj}
case *deployapi.DeploymentConfig:
p.substituteParametersInManifest(&obj.Template.ControllerTemplate.PodTemplate.DesiredState.Manifest, paramMap)
t.Items[i] = runtime.EmbeddedObject{Object: obj}
default:
glog.V(1).Infof("template.items[%v]: Parameter substitution not implemented for resource '%T'.", i, obj)
}
}
return nil
}
// substituteParametersInManifest is a helper function that iterates
// over the given manifest and substitutes all Parameter expression
// occurances with their corresponding values.
func (p *TemplateProcessor) substituteParametersInManifest(manifest *kapi.ContainerManifest, paramMap map[string]string) {
for i := range manifest.Containers {
for e := range manifest.Containers[i].Env {
envValue := &manifest.Containers[i].Env[e].Value
// Match all parameter expressions found in the given env var
for _, match := range parameterExp.FindAllStringSubmatch(*envValue, -1) {
// Substitute expression with its value, if corresponding parameter found
if len(match) > 1 {
if paramValue, found := paramMap[match[1]]; found {
*envValue = strings.Replace(*envValue, match[0], paramValue, 1)
}
}
}
}
}
}
// GenerateParameterValues generates Value for each Parameter of the given
// Template that has Generate field specified.
//
// Examples:
//
// from | value
// -----------------------------
// "test[0-9]{1}x" | "test7x"
// "[0-1]{8}" | "01001100"
// "0x[A-F0-9]{4}" | "0xB3AF"
// "[a-zA-Z0-9]{8}" | "hW4yQU5i"
func (p *TemplateProcessor) GenerateParameterValues(t *api.Template) error {
for i := range t.Parameters {
param := &t.Parameters[i]
if param.Generate != "" {
generator, ok := p.Generators[param.Generate]
if !ok {
return fmt.Errorf("template.parameters[%v]: Unable to find the '%v' generator.", i, param.Generate)
}
if generator == nil {
return fmt.Errorf("template.parameters[%v]: Invalid '%v' generator.", i, param.Generate)
}
value, err := generator.GenerateValue(param.From)
if err != nil {
return err
}
param.Value, ok = value.(string)
if !ok {
return fmt.Errorf("template.parameters[%v]: Unable to convert the generated value '%#v' to string.", i, value)
}
}
}
return nil
}