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forked from apache/beam
/
fn.go
1114 lines (997 loc) · 40.7 KB
/
fn.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 graph
import (
"fmt"
"reflect"
"github.com/apache/beam/sdks/go/pkg/beam/core/funcx"
"github.com/apache/beam/sdks/go/pkg/beam/core/sdf"
"github.com/apache/beam/sdks/go/pkg/beam/core/typex"
"github.com/apache/beam/sdks/go/pkg/beam/core/util/reflectx"
"github.com/apache/beam/sdks/go/pkg/beam/internal/errors"
)
// Fn holds either a function or struct receiver.
type Fn struct {
// Fn holds the function, if present. If Fn is nil, Recv must be
// non-nil.
Fn *funcx.Fn
// Recv hold the struct receiver, if present. If Recv is nil, Fn
// must be non-nil.
Recv interface{}
// DynFn holds the function-generator, if dynamic. If not nil, Fn
// holds the generated function.
DynFn *DynFn
// methods holds the public methods (or the function) by their beam
// names.
methods map[string]*funcx.Fn
// annotations holds the annotations of the struct.
annotations map[string][]byte
}
// Name returns the name of the function or struct.
func (f *Fn) Name() string {
if f.Fn != nil {
return f.Fn.Fn.Name()
}
t := reflectx.SkipPtr(reflect.TypeOf(f.Recv))
return fmt.Sprintf("%v.%v", t.PkgPath(), t.Name())
}
// DynFn is a generator for dynamically-created functions:
//
// gen: (name string, t reflect.Type, []byte) -> func : T
//
// where the generated function, fn : T, is re-created at runtime. This concept
// allows serialization of dynamically-generated functions, which do not have a
// valid (unique) symbol such as one created via reflect.MakeFunc.
type DynFn struct {
// Name is the name of the function. It does not have to be a valid symbol.
Name string
// T is the type of the generated function
T reflect.Type
// Data holds the data, if any, for the generator. Each function
// generator typically needs some configuration data, which is
// required by the DynFn to be encoded.
Data []byte
// Gen is the function generator. The function generator itself must be a
// function with a unique symbol.
Gen func(string, reflect.Type, []byte) reflectx.Func
}
// NewFn pre-processes a function, dynamic function or struct for graph
// construction.
func NewFn(fn interface{}) (*Fn, error) {
if gen, ok := fn.(*DynFn); ok {
f, err := funcx.New(gen.Gen(gen.Name, gen.T, gen.Data))
if err != nil {
return nil, err
}
return &Fn{Fn: f, DynFn: gen}, nil
}
val := reflect.ValueOf(fn)
switch val.Type().Kind() {
case reflect.Func:
f, err := funcx.New(reflectx.MakeFunc(fn))
if err != nil {
return nil, err
}
return &Fn{Fn: f}, nil
case reflect.Ptr:
if val.Elem().Kind() != reflect.Struct {
return nil, errors.Errorf("value %v must be ptr to struct", fn)
}
// Note that a ptr receiver is necessary if struct fields are updated in the
// user code. Otherwise, updates are simply lost.
fallthrough
case reflect.Struct:
methods := make(map[string]*funcx.Fn)
annotations := make(map[string][]byte)
af := reflect.Indirect(val).FieldByName("Annotations")
if af.IsValid() {
a, ok := af.Interface().(map[string][]byte)
if ok {
annotations = a
}
}
if methodsFuncs, ok := reflectx.WrapMethods(fn); ok {
for name, mfn := range methodsFuncs {
f, err := funcx.New(mfn)
if err != nil {
return nil, errors.Wrapf(err, "method %v invalid", name)
}
methods[name] = f
}
return &Fn{Recv: fn, methods: methods, annotations: annotations}, nil
}
// TODO(lostluck): Consider moving this into the reflectx package.
for i := 0; i < val.Type().NumMethod(); i++ {
m := val.Type().Method(i)
if m.PkgPath != "" {
continue // skip: unexported
}
if m.Name == "String" {
continue // skip: harmless
}
// CAVEAT(herohde) 5/22/2017: The type val.Type.Method.Type is not
// the same as val.Method.Type: the former has the explicit receiver.
// We'll use the receiver-less version.
// TODO(herohde) 5/22/2017: Alternatively, it looks like we could
// serialize each method, call them explicitly and avoid struct
// registration.
f, err := funcx.New(reflectx.MakeFunc(val.Method(i).Interface()))
if err != nil {
return nil, errors.Wrapf(err, "method %v invalid", m.Name)
}
methods[m.Name] = f
}
return &Fn{Recv: fn, methods: methods, annotations: annotations}, nil
default:
return nil, errors.Errorf("value %v must be function or (ptr to) struct", fn)
}
}
// Signature method names.
const (
setupName = "Setup"
startBundleName = "StartBundle"
processElementName = "ProcessElement"
finishBundleName = "FinishBundle"
teardownName = "Teardown"
createInitialRestrictionName = "CreateInitialRestriction"
splitRestrictionName = "SplitRestriction"
restrictionSizeName = "RestrictionSize"
createTrackerName = "CreateTracker"
createAccumulatorName = "CreateAccumulator"
addInputName = "AddInput"
mergeAccumulatorsName = "MergeAccumulators"
extractOutputName = "ExtractOutput"
compactName = "Compact"
// TODO: ViewFn, etc.
)
var doFnNames = []string{
setupName,
startBundleName,
processElementName,
finishBundleName,
teardownName,
createInitialRestrictionName,
splitRestrictionName,
restrictionSizeName,
createTrackerName,
}
var sdfNames = []string{
createInitialRestrictionName,
splitRestrictionName,
restrictionSizeName,
createTrackerName,
}
var combineFnNames = []string{
createAccumulatorName,
addInputName,
mergeAccumulatorsName,
extractOutputName,
compactName,
}
var lifecycleMethods map[string]struct{}
func init() {
lifecycleMethods = make(map[string]struct{})
methods := append(doFnNames, combineFnNames...)
for _, name := range methods {
lifecycleMethods[name] = struct{}{}
}
}
// lifecycleMethodName returns if the passed in string is one of the lifecycle
// method names used by the Go SDK as DoFn or CombineFn lifecycle methods. These
// are the only methods that need shims generated for them.
func IsLifecycleMethod(n string) bool {
_, ok := lifecycleMethods[n]
return ok
}
// DoFn represents a DoFn.
type DoFn Fn
// SetupFn returns the "Setup" function, if present.
func (f *DoFn) SetupFn() *funcx.Fn {
return f.methods[setupName]
}
// StartBundleFn returns the "StartBundle" function, if present.
func (f *DoFn) StartBundleFn() *funcx.Fn {
return f.methods[startBundleName]
}
// ProcessElementFn returns the "ProcessElement" function.
func (f *DoFn) ProcessElementFn() *funcx.Fn {
return f.methods[processElementName]
}
// FinishBundleFn returns the "FinishBundle" function, if present.
func (f *DoFn) FinishBundleFn() *funcx.Fn {
return f.methods[finishBundleName]
}
// TeardownFn returns the "Teardown" function, if present.
func (f *DoFn) TeardownFn() *funcx.Fn {
return f.methods[teardownName]
}
// Annotations returns the optional annotations of the DoFn, if present.
func (f *DoFn) Annotations() map[string][]byte {
return f.annotations
}
// Name returns the name of the function or struct.
func (f *DoFn) Name() string {
return (*Fn)(f).Name()
}
// IsSplittable returns whether the DoFn is a valid Splittable DoFn.
func (f *DoFn) IsSplittable() bool {
// Validation already passed, so if one SDF method is present they should
// all be present.
_, ok := f.methods[createInitialRestrictionName]
return ok
}
// SplittableDoFn represents a DoFn implementing SDF methods.
type SplittableDoFn DoFn
// CreateInitialRestrictionFn returns the "CreateInitialRestriction" function, if present.
func (f *SplittableDoFn) CreateInitialRestrictionFn() *funcx.Fn {
return f.methods[createInitialRestrictionName]
}
// SplitRestrictionFn returns the "SplitRestriction" function, if present.
func (f *SplittableDoFn) SplitRestrictionFn() *funcx.Fn {
return f.methods[splitRestrictionName]
}
// RestrictionSizeFn returns the "RestrictionSize" function, if present.
func (f *SplittableDoFn) RestrictionSizeFn() *funcx.Fn {
return f.methods[restrictionSizeName]
}
// CreateTrackerFn returns the "CreateTracker" function, if present.
func (f *SplittableDoFn) CreateTrackerFn() *funcx.Fn {
return f.methods[createTrackerName]
}
// Name returns the name of the function or struct.
func (f *SplittableDoFn) Name() string {
return (*Fn)(f).Name()
}
// RestrictionT returns the restriction type from the SDF.
func (f *SplittableDoFn) RestrictionT() reflect.Type {
return f.CreateInitialRestrictionFn().Ret[0].T
}
// TODO(herohde) 5/19/2017: we can sometimes detect whether the main input must be
// a KV or not based on the other signatures (unless we're more loose about which
// sideinputs are present). Bind should respect that.
type mainInputs int
// The following constants prefixed with "Main" represent valid numbers of DoFn
// main inputs for DoFn construction and validation.
const (
MainUnknown mainInputs = -1 // Number of inputs is unknown for DoFn validation.
MainSingle mainInputs = 1 // Number of inputs for single value elements.
MainKv mainInputs = 2 // Number of inputs for KV elements.
)
// config stores the optional configuration parameters to NewDoFn.
type config struct {
numMainIn mainInputs
}
func defaultConfig() *config {
return &config{
numMainIn: MainUnknown,
}
}
// NumMainInputs is an optional config to NewDoFn which specifies the number
// of main inputs to the DoFn being created, allowing for more complete
// validation. Valid inputs are the package constants of type mainInputs.
//
// Example usage:
// graph.NewDoFn(fn, graph.NumMainInputs(graph.MainKv))
func NumMainInputs(num mainInputs) func(*config) {
return func(cfg *config) {
cfg.numMainIn = num
}
}
// CoGBKMainInput is an optional config to NewDoFn which specifies the number
// of components of a CoGBK input to the DoFn being created, allowing for more complete
// validation.
//
// Example usage:
// var col beam.PCollection
// graph.NewDoFn(fn, graph.CoGBKMainInput(len(col.Type().Components())))
func CoGBKMainInput(components int) func(*config) {
return func(cfg *config) {
cfg.numMainIn = mainInputs(components)
}
}
// NewDoFn constructs a DoFn from the given value, if possible.
func NewDoFn(fn interface{}, options ...func(*config)) (*DoFn, error) {
ret, err := NewFn(fn)
if err != nil {
return nil, errors.WithContext(errors.Wrapf(err, "invalid DoFn"), "constructing DoFn")
}
cfg := defaultConfig()
for _, opt := range options {
opt(cfg)
}
return AsDoFn(ret, cfg.numMainIn)
}
// AsDoFn converts a Fn to a DoFn, if possible. numMainIn specifies how many
// main inputs are expected in the DoFn's method signatures. Valid inputs are
// the package constants of type mainInputs. If that number is MainUnknown then
// validation is done by best effort and may miss some edge cases.
func AsDoFn(fn *Fn, numMainIn mainInputs) (*DoFn, error) {
addContext := func(err error, fn *Fn) error {
return errors.WithContextf(err, "graph.AsDoFn: for Fn named %v", fn.Name())
}
if fn.methods == nil {
fn.methods = make(map[string]*funcx.Fn)
}
if fn.Fn != nil {
fn.methods[processElementName] = fn.Fn
}
if err := verifyValidNames("graph.AsDoFn", fn, doFnNames...); err != nil {
return nil, err
}
if _, ok := fn.methods[processElementName]; !ok {
err := errors.Errorf("failed to find %v method", processElementName)
return nil, addContext(err, fn)
}
// Validate ProcessElement has correct number of main inputs (as indicated by
// numMainIn), and that main inputs are before side inputs.
processFn := fn.methods[processElementName]
if err := validateMainInputs(fn, processFn, processElementName, numMainIn); err != nil {
return nil, addContext(err, fn)
}
// If numMainIn is unknown, we can try inferring it from the number of inputs in ProcessElement.
pos, num, _ := processFn.Inputs()
if numMainIn == MainUnknown && num == 1 {
numMainIn = MainSingle
}
// If the ProcessElement function includes side inputs or emit functions those must also be
// present in the signatures of startBundle and finishBundle.
processFnInputs := processFn.Param[pos : pos+num]
if startFn, ok := fn.methods[startBundleName]; ok {
if err := validateSideInputs(processFnInputs, startFn, startBundleName, numMainIn); err != nil {
return nil, addContext(err, fn)
}
}
if finishFn, ok := fn.methods[finishBundleName]; ok {
if err := validateSideInputs(processFnInputs, finishFn, finishBundleName, numMainIn); err != nil {
return nil, addContext(err, fn)
}
}
pos, num, ok := processFn.Emits()
var processFnEmits []funcx.FnParam
if ok {
processFnEmits = processFn.Param[pos : pos+num]
} else {
processFnEmits = processFn.Param[0:0]
}
if startFn, ok := fn.methods[startBundleName]; ok {
if err := validateEmits(processFnEmits, startFn, startBundleName); err != nil {
return nil, addContext(err, fn)
}
}
if finishFn, ok := fn.methods[finishBundleName]; ok {
if err := validateEmits(processFnEmits, finishFn, finishBundleName); err != nil {
return nil, addContext(err, fn)
}
}
// Check that Setup and Teardown have no parameters other than Context.
for _, name := range []string{setupName, teardownName} {
if method, ok := fn.methods[name]; ok {
params := method.Param
if len(params) > 1 || (len(params) == 1 && params[0].Kind != funcx.FnContext) {
err := errors.Errorf(
"method %v has invalid parameters, "+
"only allowed an optional context.Context", name)
err = errors.SetTopLevelMsgf(err,
"Method %v of DoFns should have no parameters other than "+
"an optional context.Context, but invalid parameters are "+
"present in DoFn %v.",
name, fn.Name())
return nil, addContext(err, fn)
}
}
}
// Check that none of the methods (except ProcessElement) have any return
// values other than error.
for _, name := range []string{setupName, startBundleName, finishBundleName, teardownName} {
if method, ok := fn.methods[name]; ok {
returns := method.Ret
if len(returns) > 1 || (len(returns) == 1 && returns[0].Kind != funcx.RetError) {
err := errors.Errorf(
"method %v has invalid return values, "+
"only allowed an optional error", name)
err = errors.SetTopLevelMsgf(err,
"Method %v of DoFns should have no return values other "+
"than an optional error, but invalid return values are present "+
"in DoFn %v.",
name, fn.Name())
return nil, addContext(err, fn)
}
}
}
// Check whether to perform SDF validation.
isSdf, err := validateIsSdf(fn)
if err != nil {
return nil, addContext(err, fn)
}
// Perform validation on the SDF method signatures to ensure they're valid.
if isSdf {
err := validateSdfSignatures(fn, numMainIn)
if err != nil {
return nil, addContext(err, fn)
}
}
return (*DoFn)(fn), nil
}
// validateMainInputs checks that a method has the given number of main inputs
// and that main inputs are before any side inputs.
func validateMainInputs(fn *Fn, method *funcx.Fn, methodName string, numMainIn mainInputs) error {
if numMainIn == MainUnknown {
numMainIn = MainSingle // If unknown, validate for minimum number of inputs.
}
// Make sure there are enough inputs (at least numMainIn)
pos, num, ok := method.Inputs()
if !ok {
err := errors.Errorf("%v method has no main inputs", methodName)
err = errors.SetTopLevelMsgf(err,
"Method %v in DoFn %v is missing all inputs. A main input is required.",
methodName, fn.Name())
return err
}
if num < int(numMainIn) {
err := errors.Errorf("%v method has too few main inputs", methodName)
err = errors.SetTopLevelMsgf(err,
"Method %v in DoFn %v does not have enough main inputs. "+
"%v main inputs were expected, but only %v inputs were found.",
methodName, fn.Name(), numMainIn, num)
return err
}
// Check that the first input is not an Iter or ReIter (those aren't valid
// as the first main input).
first := method.Param[pos].Kind
if first != funcx.FnValue {
err := errors.New("first main input parameter must be a value type")
err = errors.SetTopLevelMsgf(err,
"Method %v of DoFns should always have the first input be a value type, "+
"but it has an Iter or ReIter first in DoFn %v.",
processElementName, fn.Name())
return errors.WithContextf(err, "method %v", processElementName)
}
return nil
}
// validateEmits compares the emits found in a DoFn method signature with the emits found in
// the signature for ProcessElement, and performs validation that those match. This function
// should only be used to validate methods that are expected to have the same emit parameters as
// ProcessElement.
func validateEmits(processFnEmits []funcx.FnParam, method *funcx.Fn, methodName string) error {
posMethodEmits, numMethodEmits, ok := method.Emits()
numProcessEmits := len(processFnEmits)
// Handle cases where method has no emits.
if !ok {
if numProcessEmits == 0 { // We're good, expected no emits.
return nil
}
// Error, missing emits.
err := errors.Errorf("emit parameters expected in method %v", methodName)
return errors.SetTopLevelMsgf(err,
"Missing emit parameters in the %v method of a DoFn. "+
"If emit parameters are present in %v those parameters must also be present in %v.",
methodName, processElementName, methodName)
}
// Error if number of emits doesn't match.
if numMethodEmits != numProcessEmits {
err := errors.Errorf("number of emits in method %v does not match method %v: got %d, expected %d",
methodName, processElementName, numMethodEmits, numProcessEmits)
return errors.SetTopLevelMsgf(err,
"Incorrect number of emit parameters in the %v method of a DoFn. "+
"The emit parameters should match those of the %v method.",
methodName, processElementName)
}
// Error if there's a type mismatch.
methodEmits := method.Param[posMethodEmits : posMethodEmits+numMethodEmits]
for i := 0; i < numProcessEmits; i++ {
if processFnEmits[i].T != methodEmits[i].T {
var err error = &funcx.TypeMismatchError{Got: methodEmits[i].T, Want: processFnEmits[i].T}
err = errors.Wrapf(err, "emit parameter in method %v does not match emit parameter in %v",
methodName, processElementName)
return errors.SetTopLevelMsgf(err,
"Incorrect emit parameters in the %v method of a DoFn. "+
"The emit parameters should match those of the %v method.",
methodName, processElementName)
}
}
return nil
}
// validateSideInputs compares the inputs found in a DoFn method signature with the inputs found
// in the signature for ProcessElement, and performs validation to check that the side inputs
// match. This function should only be used to validate methods that are expected to have matching
// side inputs to ProcessElement.
func validateSideInputs(processFnInputs []funcx.FnParam, method *funcx.Fn, methodName string, numMainIn mainInputs) error {
if numMainIn == MainUnknown {
return validateSideInputsNumUnknown(processFnInputs, method, methodName)
}
numProcessIn := len(processFnInputs)
numSideIn := numProcessIn - int(numMainIn)
posMethodIn, numMethodIn, ok := method.Inputs()
// Handle cases where method has no inputs.
if !ok {
if numSideIn == 0 { // We're good, expected no side inputs.
return nil
}
// Error, missing side inputs.
err := errors.Errorf("side inputs expected in method %v", methodName)
return errors.SetTopLevelMsgf(err,
"Missing side inputs in the %v method of a DoFn. "+
"If side inputs are present in %v those side inputs must also be present in %v.",
methodName, processElementName, methodName)
}
// Error if number of side inputs doesn't match.
if numMethodIn != numSideIn {
err := errors.Errorf("number of side inputs in method %v does not match method %v: got %d, expected %d",
methodName, processElementName, numMethodIn, numSideIn)
return errors.SetTopLevelMsgf(err,
"Incorrect number of side inputs in the %v method of a DoFn. "+
"The side inputs should match those of the %v method.",
methodName, processElementName)
}
// Error if there's a type mismatch.
methodInputs := method.Param[posMethodIn : posMethodIn+numMethodIn]
sideInputs := processFnInputs[numMainIn:] // Skip main inputs in ProcessFn
for i := 0; i < len(sideInputs); i++ {
if sideInputs[i].T != methodInputs[i].T {
var err error = &funcx.TypeMismatchError{Got: methodInputs[i].T, Want: sideInputs[i].T}
err = errors.Wrapf(err, "side input in method %v does not match side input in %v",
methodName, processElementName)
return errors.SetTopLevelMsgf(err,
"Incorrect side inputs in the %v method of a DoFn. "+
"The side inputs should match those of the %v method.",
methodName, processElementName)
}
}
return nil
}
// validateSideInputsNumUnknown does similar validation as validateSideInputs, but for an unknown
// number of main inputs.
func validateSideInputsNumUnknown(processFnInputs []funcx.FnParam, method *funcx.Fn, methodName string) error {
// Note: By the time this is called, we should have already know that ProcessElement has at
// least two inputs, and the second input is ambiguous (could be either a main input or side
// input). Since we don't know how to interpret the second input, these checks will be more
// permissive than they would be otherwise.
posMethodIn, numMethodIn, ok := method.Inputs()
numProcessIn := len(processFnInputs)
// Handle cases where method has no inputs.
if !ok {
// If there's no inputs, this is fine, as the ProcessElement method could be a
// CoGBK, and not have side inputs.
return nil
}
// Error if number of side inputs doesn't match any of the possible numbers of side inputs,
// defined below.
numSideInSingle := numProcessIn - int(MainSingle)
numSideInKv := numProcessIn - int(MainKv)
if numMethodIn != numSideInSingle && numMethodIn != numSideInKv {
err := errors.Errorf("number of side inputs in method %v does not match method %v: got %d, expected either %d or %d",
methodName, processElementName, numMethodIn, numSideInSingle, numSideInKv)
return errors.SetTopLevelMsgf(err,
"Incorrect number of side inputs in the %v method of a DoFn. "+
"The side inputs should match those of the %v method.",
methodName, processElementName)
}
// Error if there's a type mismatch.
methodInputs := method.Param[posMethodIn : posMethodIn+numMethodIn]
// If there's N inputs in the method, then we compare with the last N inputs to processElement.
offset := numProcessIn - numMethodIn
sideInputs := processFnInputs[offset:]
for i := 0; i < numMethodIn; i++ {
if sideInputs[i].T != methodInputs[i].T {
var err error = &funcx.TypeMismatchError{Got: methodInputs[i].T, Want: sideInputs[i].T}
err = errors.Wrapf(err, "side input in method %v does not match side input in %v",
methodName, processElementName)
return errors.SetTopLevelMsgf(err,
"Incorrect side inputs in the %v method of a DoFn. "+
"The side inputs should match those of the %v method.",
methodName, processElementName)
}
}
return nil
}
// validateIsSdf checks whether a Fn either is or is not an SDF, and returns
// true if it is, false if it isn't, or an error if it doesn't fulfill the
// requirements for either case.
//
// For a Fn to be an SDF it must:
// * Implement all the SDF methods.
// * Include an RTracker parameter in ProcessElement.
// For a Fn to not be an SDF, it must:
// * Implement none of the SDF methods.
// * Not include an RTracker parameter in ProcessElement.
func validateIsSdf(fn *Fn) (bool, error) {
// Store missing method names so we can output them to the user if validation fails.
var missing []string
for _, name := range sdfNames {
_, ok := fn.methods[name]
if !ok {
missing = append(missing, name)
}
}
var isSdf bool
switch len(missing) {
case 0: // All SDF methods present.
isSdf = true
case len(sdfNames): // No SDF methods.
isSdf = false
default: // Anything else means an invalid # of SDF methods.
err := errors.Errorf("not all SplittableDoFn methods are present. Missing methods: %v", missing)
return false, err
}
processFn := fn.methods[processElementName]
if pos, ok := processFn.RTracker(); ok != isSdf {
if ok {
err := errors.Errorf("method %v has sdf.RTracker as param %v, expected none",
processElementName, pos)
return false, errors.SetTopLevelMsgf(err, "Method %v has an sdf.RTracker parameter at index %v, "+
"but is not part of a splittable DoFn. sdf.RTracker is invalid in %v in non-splittable DoFns.",
processElementName, pos, processElementName)
}
pos, _, _ = processFn.Inputs()
err := errors.Errorf("method %v missing sdf.RTracker, expected one at index %v",
processElementName, pos)
return false, errors.SetTopLevelMsgf(err, "Method %v is missing an sdf.RTracker "+
"parameter despite being part of a splittable DoFn. %v in splittable DoFns requires an "+
"sdf.RTracker parameter before main inputs (in this case, at index %v).",
processElementName, processElementName, pos)
}
return isSdf, nil
}
// validateSdfSignatures validates that types in the SDF methods of a Fn are
// consistent with each other (for example, element and restriction types should
// match with each other). Returns an error if one is found, or nil if the
// types are all valid.
// TODO(BEAM-3301): Once SDF documentation is added to ParDo, add a comment
// here to refer to that for specific details about what needs to be consistent.
func validateSdfSignatures(fn *Fn, numMainIn mainInputs) error {
num := int(numMainIn)
// If number of main inputs is ambiguous, we check for consistency against
// CreateInitialRestriction.
if numMainIn == MainUnknown {
initialRestFn := fn.methods[createInitialRestrictionName]
paramNum := len(initialRestFn.Param)
switch paramNum {
case int(MainSingle), int(MainKv):
num = paramNum
default: // Can't infer because method has invalid # of main inputs.
err := errors.Errorf("invalid number of params in method %v. got: %v, want: %v or %v",
createInitialRestrictionName, paramNum, int(MainSingle), int(MainKv))
return errors.SetTopLevelMsgf(err, "Invalid number of parameters in method %v. "+
"Got: %v, Want: %v or %v. Check that the signature conforms to the expected signature for %v, "+
"and that elements in SDF method parameters match elements in %v.",
createInitialRestrictionName, paramNum, int(MainSingle), int(MainKv), createInitialRestrictionName, processElementName)
}
}
if err := validateSdfSigNumbers(fn, num); err != nil {
return err
}
if err := validateSdfSigTypes(fn, num); err != nil {
return err
}
return nil
}
// validateSdfSigNumbers validates the number of parameters and return values
// in each SDF method in the given Fn, and returns an error if a method has an
// invalid/unexpected number.
func validateSdfSigNumbers(fn *Fn, num int) error {
paramNums := map[string]int{
createInitialRestrictionName: num,
splitRestrictionName: num + 1,
restrictionSizeName: num + 1,
createTrackerName: 1,
}
returnNum := 1 // TODO(BEAM-3301): Enable optional error params in SDF methods.
for _, name := range sdfNames {
method := fn.methods[name]
if len(method.Param) != paramNums[name] {
err := errors.Errorf("unexpected number of params in method %v. got: %v, want: %v",
name, len(method.Param), paramNums[name])
return errors.SetTopLevelMsgf(err, "Unexpected number of parameters in method %v. "+
"Got: %v, Want: %v. Check that the signature conforms to the expected signature for %v, "+
"and that elements in SDF method parameters match elements in %v.",
name, len(method.Param), paramNums[name], name, processElementName)
}
if len(method.Ret) != returnNum {
err := errors.Errorf("unexpected number of returns in method %v. got: %v, want: %v",
name, len(method.Ret), returnNum)
return errors.SetTopLevelMsgf(err, "Unexpected number of return values in method %v. "+
"Got: %v, Want: %v. Check that the signature conforms to the expected signature for %v.",
name, len(method.Ret), returnNum, name)
}
}
return nil
}
// validateSdfSigTypes validates the types of the parameters and return values
// in each SDF method in the given Fn, and returns an error if a method has an
// invalid/mismatched type. Assumes that the number of parameters and return
// values has already been validated.
func validateSdfSigTypes(fn *Fn, num int) error {
restrictionT := fn.methods[createInitialRestrictionName].Ret[0].T
rTrackerT := reflect.TypeOf((*sdf.RTracker)(nil)).Elem()
for _, name := range sdfNames {
method := fn.methods[name]
switch name {
case createInitialRestrictionName:
if err := validateSdfElementT(fn, createInitialRestrictionName, method, num); err != nil {
return err
}
case splitRestrictionName:
if err := validateSdfElementT(fn, splitRestrictionName, method, num); err != nil {
return err
}
if method.Param[num].T != restrictionT {
err := errors.Errorf("mismatched restriction type in method %v, param %v. got: %v, want: %v",
splitRestrictionName, num, method.Param[num].T, restrictionT)
return errors.SetTopLevelMsgf(err, "Mismatched restriction type in method %v, "+
"parameter at index %v. Got: %v, Want: %v (from method %v). "+
"Ensure that all restrictions in an SDF are the same type.",
splitRestrictionName, num, method.Param[num].T, restrictionT, createInitialRestrictionName)
}
if method.Ret[0].T.Kind() != reflect.Slice ||
method.Ret[0].T.Elem() != restrictionT {
err := errors.Errorf("invalid output type in method %v, return %v. got: %v, want: %v",
splitRestrictionName, 0, method.Ret[0].T, reflect.SliceOf(restrictionT))
return errors.SetTopLevelMsgf(err, "Invalid output type in method %v, "+
"return value at index %v. Got: %v, Want: %v (from method %v). "+
"Ensure that all restrictions in an SDF are the same type, and that %v returns a slice.",
splitRestrictionName, 0, method.Ret[0].T, reflect.SliceOf(restrictionT), createInitialRestrictionName, splitRestrictionName)
}
case restrictionSizeName:
if err := validateSdfElementT(fn, restrictionSizeName, method, num); err != nil {
return err
}
if method.Param[num].T != restrictionT {
err := errors.Errorf("mismatched restriction type in method %v, param %v. got: %v, want: %v",
restrictionSizeName, num, method.Param[num].T, restrictionT)
return errors.SetTopLevelMsgf(err, "Mismatched restriction type in method %v, "+
"parameter at index %v. Got: %v, Want: %v (from method %v). "+
"Ensure that all restrictions in an SDF are the same type.",
restrictionSizeName, num, method.Param[num].T, restrictionT, createInitialRestrictionName)
}
if method.Ret[0].T != reflectx.Float64 {
err := errors.Errorf("invalid output type in method %v, return %v. got: %v, want: %v",
restrictionSizeName, 0, method.Ret[0].T, reflectx.Float64)
return errors.SetTopLevelMsgf(err, "Invalid output type in method %v, "+
"return value at index %v. Got: %v, Want: %v. Sizing information in SDF methods must be in float64.",
restrictionSizeName, 0, method.Ret[0].T, reflectx.Float64)
}
case createTrackerName:
if method.Param[0].T != restrictionT {
err := errors.Errorf("mismatched restriction type in method %v, param %v. got: %v, want: %v",
createTrackerName, 0, method.Param[0].T, restrictionT)
return errors.SetTopLevelMsgf(err, "Mismatched restriction type in method %v, "+
"parameter at index %v. Got: %v, Want: %v (from method %v). "+
"Ensure that all restrictions in an SDF are the same type.",
createTrackerName, 0, method.Param[0].T, restrictionT, createInitialRestrictionName)
}
if method.Ret[0].T.Implements(rTrackerT) == false {
err := errors.Errorf("invalid output type in method %v, return %v: %v does not implement sdf.RTracker",
createTrackerName, 0, method.Ret[0].T)
return errors.SetTopLevelMsgf(err, "Invalid output type in method %v, "+
"return value at index %v (type: %v). Output of method %v must implement sdf.RTracker.",
createTrackerName, 0, method.Ret[0].T, createTrackerName)
}
processFn := fn.methods[processElementName]
pos, _ := processFn.RTracker()
if method.Ret[0].T != processFn.Param[pos].T {
err := errors.Errorf("mismatched output type in method %v, return %v: got: %v, want: %v",
createTrackerName, 0, method.Ret[0].T, processFn.Param[pos].T)
return errors.SetTopLevelMsgf(err, "Mismatched output type in method %v, "+
"return value at index %v. Got: %v, Want: %v (from method %v).",
createTrackerName, 0, method.Ret[0].T, processFn.Param[pos].T, processElementName)
}
}
}
return nil
}
// validateSdfElementT validates that element types in an SDF method are
// consistent with the ProcessElement method. This method assumes that the
// first 'num' parameters to the SDF method are the elements.
func validateSdfElementT(fn *Fn, name string, method *funcx.Fn, num int) error {
// ProcessElement is the most canonical source of the element type. We can
// processFn is valid by this point and skip unnecessary validation.
processFn := fn.methods[processElementName]
pos, _, _ := processFn.Inputs()
for i := 0; i < num; i++ {
if method.Param[i].T != processFn.Param[pos+i].T {
err := errors.Errorf("mismatched element type in method %v, param %v. got: %v, want: %v",
name, i, method.Param[i].T, processFn.Param[pos+i].T)
return errors.SetTopLevelMsgf(err, "Mismatched element type in method %v, "+
"parameter at index %v. Got: %v, Want: %v (from method %v). "+
"Ensure that element parameters in SDF methods have consistent types with element parameters in %v.",
name, i, method.Param[i].T, processFn.Param[pos+i].T, processElementName, processElementName)
}
}
return nil
}
// CombineFn represents a CombineFn.
type CombineFn Fn
// SetupFn returns the "Setup" function, if present.
func (f *CombineFn) SetupFn() *funcx.Fn {
return f.methods[setupName]
}
// CreateAccumulatorFn returns the "CreateAccumulator" function, if present.
func (f *CombineFn) CreateAccumulatorFn() *funcx.Fn {
return f.methods[createAccumulatorName]
}
// AddInputFn returns the "AddInput" function, if present.
func (f *CombineFn) AddInputFn() *funcx.Fn {
return f.methods[addInputName]
}
// MergeAccumulatorsFn returns the "MergeAccumulators" function. If it is the only
// method present, then InputType == AccumulatorType == OutputType.
func (f *CombineFn) MergeAccumulatorsFn() *funcx.Fn {
return f.methods[mergeAccumulatorsName]
}
// ExtractOutputFn returns the "ExtractOutput" function, if present.
func (f *CombineFn) ExtractOutputFn() *funcx.Fn {
return f.methods[extractOutputName]
}
// CompactFn returns the "Compact" function, if present.
func (f *CombineFn) CompactFn() *funcx.Fn {
return f.methods[compactName]
}
// TeardownFn returns the "Teardown" function, if present.
func (f *CombineFn) TeardownFn() *funcx.Fn {
return f.methods[teardownName]
}
// Name returns the name of the function or struct.
func (f *CombineFn) Name() string {
return (*Fn)(f).Name()
}
// NewCombineFn constructs a CombineFn from the given value, if possible.
func NewCombineFn(fn interface{}) (*CombineFn, error) {
ret, err := NewFn(fn)
if err != nil {
return nil, errors.WithContext(errors.Wrapf(err, "invalid CombineFn"), "constructing CombineFn")
}
return AsCombineFn(ret)
}
// AsCombineFn converts a Fn to a CombineFn, if possible.
func AsCombineFn(fn *Fn) (*CombineFn, error) {
const fnKind = "graph.AsCombineFn"
if fn.methods == nil {
fn.methods = make(map[string]*funcx.Fn)
}
if fn.Fn != nil {
fn.methods[mergeAccumulatorsName] = fn.Fn
}
if err := verifyValidNames(fnKind, fn, setupName, createAccumulatorName, addInputName, mergeAccumulatorsName, extractOutputName, compactName, teardownName); err != nil {
return nil, err
}
mergeFn, ok := fn.methods[mergeAccumulatorsName]
if !ok {
return nil, errors.Errorf("%v: failed to find required %v method on type: %v", fnKind, mergeAccumulatorsName, fn.Name())
}
// CombineFn methods must satisfy the following:
// CreateAccumulator func() (A, error?)
// AddInput func(A, I) (A, error?)
// MergeAccumulators func(A, A) (A, error?)
// ExtractOutput func(A) (O, error?)
// This means that the other signatures *must* match the type used in MergeAccumulators.
if len(mergeFn.Ret) <= 0 {
return nil, errors.Errorf("%v: %v requires at least 1 return value. : %v", fnKind, mergeAccumulatorsName, mergeFn)
}
accumType := mergeFn.Ret[0].T
for _, mthd := range []struct {
name string
sigFunc func(fx *funcx.Fn, accumType reflect.Type) *funcx.Signature
}{
{mergeAccumulatorsName, func(fx *funcx.Fn, accumType reflect.Type) *funcx.Signature {
return funcx.Replace(mergeAccumulatorsSig, typex.TType, accumType)
}},
{createAccumulatorName, func(fx *funcx.Fn, accumType reflect.Type) *funcx.Signature {
return funcx.Replace(createAccumulatorSig, typex.TType, accumType)