/
templating.go
78 lines (66 loc) · 1.94 KB
/
templating.go
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package kubernetes
import (
"bytes"
"fmt"
"io"
"github.com/ghodss/yaml"
"k8s.io/apimachinery/pkg/util/validation"
)
// DefaultNamespace to generate configuration for
const DefaultNamespace = "istio-system"
const (
// Optional output formatting for configuration
YAML = iota
)
// NewConfigGenerator constructs and validate a ConfigGenerator. Setting sensible defaults which can be overridden later
func NewConfigGenerator(name string, handler HandlerSpec, instance BaseInstance, rule Rule) (*ConfigGenerator, error) {
if name == "" {
return nil, fmt.Errorf("name must be provided")
}
errs := validation.IsDNS1123Label(name)
if len(errs) > 0 {
var errStr string
for _, e := range errs {
errStr += e + "\n"
}
return nil, fmt.Errorf("provided name %s fails Kubernetes validation: %s", name, errStr)
}
return &ConfigGenerator{
handler: handler,
instance: instance,
rule: rule,
name: name,
namespace: DefaultNamespace,
outputAs: YAML,
}, nil
}
// OutputAll required manifests(instance, handler,rule) to provided writer
func (cg *ConfigGenerator) OutputAll(w io.Writer) error {
buffer := bytes.Buffer{}
objs := []*IstioResource{
getBaseResource(cg.name, cg.namespace, handlerKind).spec(cg.handler),
getBaseResource(cg.name, cg.namespace, instanceKind).spec(cg.instance),
getBaseResource(cg.name, cg.namespace, ruleKind).spec(cg.rule),
}
for _, obj := range objs {
b, err := cg.marshalIstioResource(obj)
if err != nil {
return err
}
buffer.Write(b)
buffer.Write([]byte("---\n"))
}
_, err := w.Write(buffer.Bytes())
return err
}
// SetNamespace the configuration should be generated for
func (cg *ConfigGenerator) SetNamespace(ns string) *ConfigGenerator {
cg.namespace = ns
return cg
}
func (cg *ConfigGenerator) marshalIstioResource(obj *IstioResource) ([]byte, error) {
if cg.outputAs == YAML {
return yaml.Marshal(obj)
}
return nil, fmt.Errorf("currently unsupported output format provided")
}