// SetList sets the given list object's Items member have the elements given in
// objects.
// Returns an error if list is not a List type (does not have an Items member),
// or if any of the objects are not of the right type.
// TODO: move me to pkg/api/meta
func SetList(list Object, objects []Object) error {
itemsPtr, err := GetItemsPtr(list)
if err != nil {
return err
}
items, err := conversion.EnforcePtr(itemsPtr)
if err != nil {
return err
}
if items.Type() == objectSliceType {
items.Set(reflect.ValueOf(objects))
return nil
}
slice := reflect.MakeSlice(items.Type(), len(objects), len(objects))
for i := range objects {
dest := slice.Index(i)
src, err := conversion.EnforcePtr(objects[i])
if err != nil {
return err
}
if src.Type().AssignableTo(dest.Type()) {
dest.Set(src)
} else if src.Type().ConvertibleTo(dest.Type()) {
dest.Set(src.Convert(dest.Type()))
} else {
return fmt.Errorf("item[%d]: Type mismatch: Expected %v, got %v", i, dest.Type(), src.Type())
}
}
items.Set(slice)
return nil
}
// ExtractList returns obj's Items element as an array of runtime.Objects.
// Returns an error if obj is not a List type (does not have an Items member).
// TODO: move me to pkg/api/meta
func ExtractList(obj Object) ([]Object, error) {
itemsPtr, err := GetItemsPtr(obj)
if err != nil {
return nil, err
}
items, err := conversion.EnforcePtr(itemsPtr)
if err != nil {
return nil, err
}
list := make([]Object, items.Len())
for i := range list {
raw := items.Index(i)
var found bool
switch raw.Kind() {
case reflect.Interface, reflect.Ptr:
list[i], found = raw.Interface().(Object)
default:
list[i], found = raw.Addr().Interface().(Object)
}
if !found {
return nil, fmt.Errorf("item[%v]: Expected object, got %#v(%s)", i, raw.Interface(), raw.Kind())
}
}
return list, nil
}
// CreateObj adds a new object at a key unless it already exists. 'ttl' is time-to-live in seconds,
// and 0 means forever. If no error is returned and out is not nil, out will be set to the read value
// from etcd.
func (h *EtcdHelper) CreateObj(key string, obj, out runtime.Object, ttl uint64) error {
key = h.PrefixEtcdKey(key)
data, err := h.Codec.Encode(obj)
if err != nil {
return err
}
if h.Versioner != nil {
if version, err := h.Versioner.ObjectResourceVersion(obj); err == nil && version != 0 {
return errors.New("resourceVersion may not be set on objects to be created")
}
}
startTime := time.Now()
response, err := h.Client.Create(key, string(data), ttl)
recordEtcdRequestLatency("create", getTypeName(obj), startTime)
if err != nil {
return err
}
if out != nil {
if _, err := conversion.EnforcePtr(out); err != nil {
panic("unable to convert output object to pointer")
}
_, _, err = h.extractObj(response, err, out, false, false)
}
return err
}
// addObjectParams converts a runtime.Object into a set of go-restful Param() definitions on the route.
// The object must be a pointer to a struct; only fields at the top level of the struct that are not
// themselves interfaces or structs are used; only fields with a json tag that is non empty (the standard
// Go JSON behavior for omitting a field) become query parameters. The name of the query parameter is
// the JSON field name. If a description struct tag is set on the field, that description is used on the
// query parameter. In essence, it converts a standard JSON top level object into a query param schema.
func addObjectParams(ws *restful.WebService, route *restful.RouteBuilder, obj interface{}) error {
sv, err := conversion.EnforcePtr(obj)
if err != nil {
return err
}
st := sv.Type()
switch st.Kind() {
case reflect.Struct:
for i := 0; i < st.NumField(); i++ {
name := st.Field(i).Name
sf, ok := st.FieldByName(name)
if !ok {
continue
}
switch sf.Type.Kind() {
case reflect.Interface, reflect.Struct:
default:
jsonTag := sf.Tag.Get("json")
if len(jsonTag) == 0 {
continue
}
jsonName := strings.SplitN(jsonTag, ",", 2)[0]
if len(jsonName) == 0 {
continue
}
desc := sf.Tag.Get("description")
route.Param(ws.QueryParameter(jsonName, desc).DataType(typeToJSON(sf.Type.Name())))
}
}
}
return nil
}
func (h *EtcdHelper) extractObj(response *etcd.Response, inErr error, objPtr runtime.Object, ignoreNotFound, prevNode bool) (body string, node *etcd.Node, err error) {
if response != nil {
if prevNode {
node = response.PrevNode
} else {
node = response.Node
}
}
if inErr != nil || node == nil || len(node.Value) == 0 {
if ignoreNotFound {
v, err := conversion.EnforcePtr(objPtr)
if err != nil {
return "", nil, err
}
v.Set(reflect.Zero(v.Type()))
return "", nil, nil
} else if inErr != nil {
return "", nil, inErr
}
return "", nil, fmt.Errorf("unable to locate a value on the response: %#v", response)
}
body = node.Value
err = h.Codec.DecodeInto([]byte(body), objPtr)
if h.Versioner != nil {
_ = h.Versioner.UpdateObject(objPtr, node.Expiration, node.ModifiedIndex)
// being unable to set the version does not prevent the object from being extracted
}
return body, node, err
}
// ListMetaFor returns a pointer to a provided object's ListMeta,
// or an error if the object does not have that pointer.
// TODO: allow runtime.Unknown to extract this object
func ListMetaFor(obj runtime.Object) (*ListMeta, error) {
v, err := conversion.EnforcePtr(obj)
if err != nil {
return nil, err
}
var meta *ListMeta
err = runtime.FieldPtr(v, "ListMeta", &meta)
return meta, err
}
// DeleteObj removes the specified key and returns the value that existed at that spot.
func (h *EtcdHelper) DeleteObj(key string, out runtime.Object) error {
key = h.PrefixEtcdKey(key)
if _, err := conversion.EnforcePtr(out); err != nil {
panic("unable to convert output object to pointer")
}
startTime := time.Now()
response, err := h.Client.Delete(key, false)
recordEtcdRequestLatency("delete", getTypeName(out), startTime)
if !IsEtcdNotFound(err) {
// if the object that existed prior to the delete is returned by etcd, update out.
if err != nil || response.PrevNode != nil {
_, _, err = h.extractObj(response, err, out, false, true)
}
}
return err
}
// fieldPtr puts the address of fieldName, which must be a member of v,
// into dest, which must be an address of a variable to which this field's
// address can be assigned.
func FieldPtr(v reflect.Value, fieldName string, dest interface{}) error {
field := v.FieldByName(fieldName)
if !field.IsValid() {
return fmt.Errorf("couldn't find %v field in %#v", fieldName, v.Interface())
}
v, err := conversion.EnforcePtr(dest)
if err != nil {
return err
}
field = field.Addr()
if field.Type().AssignableTo(v.Type()) {
v.Set(field)
return nil
}
if field.Type().ConvertibleTo(v.Type()) {
v.Set(field.Convert(v.Type()))
return nil
}
return fmt.Errorf("couldn't assign/convert %v to %v", field.Type(), v.Type())
}
// GetItemsPtr returns a pointer to the list object's Items member.
// If 'list' doesn't have an Items member, it's not really a list type
// and an error will be returned.
// This function will either return a pointer to a slice, or an error, but not both.
func GetItemsPtr(list Object) (interface{}, error) {
v, err := conversion.EnforcePtr(list)
if err != nil {
return nil, err
}
items := v.FieldByName("Items")
if !items.IsValid() {
return nil, fmt.Errorf("no Items field in %#v", list)
}
switch items.Kind() {
case reflect.Interface, reflect.Ptr:
target := reflect.TypeOf(items.Interface()).Elem()
if target.Kind() != reflect.Slice {
return nil, fmt.Errorf("items: Expected slice, got %s", target.Kind())
}
return items.Interface(), nil
case reflect.Slice:
return items.Addr().Interface(), nil
default:
return nil, fmt.Errorf("items: Expected slice, got %s", items.Kind())
}
}
// SetObj marshals obj via json, and stores under key. Will do an atomic update if obj's ResourceVersion
// field is set. 'ttl' is time-to-live in seconds, and 0 means forever. If no error is returned and out is
// not nil, out will be set to the read value from etcd.
func (h *EtcdHelper) SetObj(key string, obj, out runtime.Object, ttl uint64) error {
var response *etcd.Response
data, err := h.Codec.Encode(obj)
if err != nil {
return err
}
key = h.PrefixEtcdKey(key)
create := true
if h.Versioner != nil {
if version, err := h.Versioner.ObjectResourceVersion(obj); err == nil && version != 0 {
create = false
startTime := time.Now()
response, err = h.Client.CompareAndSwap(key, string(data), ttl, "", version)
recordEtcdRequestLatency("compareAndSwap", getTypeName(obj), startTime)
if err != nil {
return err
}
}
}
if create {
// Create will fail if a key already exists.
startTime := time.Now()
response, err = h.Client.Create(key, string(data), ttl)
recordEtcdRequestLatency("create", getTypeName(obj), startTime)
}
if err != nil {
return err
}
if out != nil {
if _, err := conversion.EnforcePtr(out); err != nil {
panic("unable to convert output object to pointer")
}
_, _, err = h.extractObj(response, err, out, false, false)
}
return err
}
// decodeNodeList walks the tree of each node in the list and decodes into the specified object
func (h *EtcdHelper) decodeNodeList(nodes []*etcd.Node, slicePtr interface{}) error {
trace := util.NewTrace("decodeNodeList " + getTypeName(slicePtr))
defer trace.LogIfLong(500 * time.Millisecond)
v, err := conversion.EnforcePtr(slicePtr)
if err != nil || v.Kind() != reflect.Slice {
// This should not happen at runtime.
panic("need ptr to slice")
}
for _, node := range nodes {
if node.Dir {
trace.Step("Decoding dir " + node.Key + " START")
if err := h.decodeNodeList(node.Nodes, slicePtr); err != nil {
return err
}
trace.Step("Decoding dir " + node.Key + " END")
continue
}
if obj, found := h.getFromCache(node.ModifiedIndex); found {
v.Set(reflect.Append(v, reflect.ValueOf(obj).Elem()))
} else {
obj := reflect.New(v.Type().Elem())
if err := h.Codec.DecodeInto([]byte(node.Value), obj.Interface().(runtime.Object)); err != nil {
return err
}
if h.Versioner != nil {
// being unable to set the version does not prevent the object from being extracted
_ = h.Versioner.UpdateObject(obj.Interface().(runtime.Object), node.Expiration, node.ModifiedIndex)
}
v.Set(reflect.Append(v, obj.Elem()))
if node.ModifiedIndex != 0 {
h.addToCache(node.ModifiedIndex, obj.Interface().(runtime.Object))
}
}
}
trace.Step(fmt.Sprintf("Decoded %v nodes", len(nodes)))
return nil
}
// GuaranteedUpdate calls "tryUpdate()" to update key "key" that is of type "ptrToType". It keeps
// calling tryUpdate() and retrying the update until success if there is etcd index conflict. Note that object
// passed to tryUpdate() may change across invocations of tryUpdate() if other writers are simultaneously
// updating it, so tryUpdate() needs to take into account the current contents of the object when
// deciding how the updated object (that it returns) should look.
//
// Example:
//
// h := &util.EtcdHelper{client, encoding, versioning}
// err := h.GuaranteedUpdate("myKey", &MyType{}, true, func(input runtime.Object, res ResponseMeta) (runtime.Object, *uint64, error) {
// // Before each invocation of the user-defined function, "input" is reset to etcd's current contents for "myKey".
//
// cur := input.(*MyType) // Guaranteed to succeed.
//
// // Make a *modification*.
// cur.Counter++
//
// // Return the modified object. Return an error to stop iterating. Return a uint64 to alter
// // the TTL on the object, or nil to keep it the same value.
// return cur, nil, nil
// })
//
func (h *EtcdHelper) GuaranteedUpdate(key string, ptrToType runtime.Object, ignoreNotFound bool, tryUpdate EtcdUpdateFunc) error {
v, err := conversion.EnforcePtr(ptrToType)
if err != nil {
// Panic is appropriate, because this is a programming error.
panic("need ptr to type")
}
key = h.PrefixEtcdKey(key)
for {
obj := reflect.New(v.Type()).Interface().(runtime.Object)
origBody, node, res, err := h.bodyAndExtractObj(key, obj, ignoreNotFound)
if err != nil {
return err
}
meta := ResponseMeta{}
if node != nil {
meta.TTL = node.TTL
if node.Expiration != nil {
meta.Expiration = node.Expiration
}
meta.ResourceVersion = node.ModifiedIndex
}
// Get the object to be written by calling tryUpdate.
ret, newTTL, err := tryUpdate(obj, meta)
if err != nil {
return err
}
index := uint64(0)
ttl := uint64(0)
if node != nil {
index = node.ModifiedIndex
if node.TTL > 0 {
ttl = uint64(node.TTL)
}
} else if res != nil {
index = res.EtcdIndex
}
if newTTL != nil {
ttl = *newTTL
}
data, err := h.Codec.Encode(ret)
if err != nil {
return err
}
// First time this key has been used, try creating new value.
if index == 0 {
startTime := time.Now()
response, err := h.Client.Create(key, string(data), ttl)
recordEtcdRequestLatency("create", getTypeName(ptrToType), startTime)
if IsEtcdNodeExist(err) {
continue
}
_, _, err = h.extractObj(response, err, ptrToType, false, false)
return err
}
if string(data) == origBody {
return nil
}
startTime := time.Now()
// Swap origBody with data, if origBody is the latest etcd data.
response, err := h.Client.CompareAndSwap(key, string(data), ttl, origBody, index)
recordEtcdRequestLatency("compareAndSwap", getTypeName(ptrToType), startTime)
if IsEtcdTestFailed(err) {
// Try again.
continue
}
_, _, err = h.extractObj(response, err, ptrToType, false, false)
return err
}
}