hugo/hugolib/doctree/support.go
Bjørn Erik Pedersen 7285e74090
all: Rework page store, add a dynacache, improve partial rebuilds, and some general spring cleaning
There are some breaking changes in this commit, see #11455.

Closes #11455
Closes #11549

This fixes a set of bugs (see issue list) and it is also paying some technical debt accumulated over the years. We now build with Staticcheck enabled in the CI build.

The performance should be about the same as before for regular sized Hugo sites, but it should perform and scale much better to larger data sets, as objects that uses lots of memory (e.g. rendered Markdown, big JSON files read into maps with transform.Unmarshal etc.) will now get automatically garbage collected if needed. Performance on partial rebuilds when running the server in fast render mode should be the same, but the change detection should be much more accurate.

A list of the notable new features:

* A new dependency tracker that covers (almost) all of Hugo's API and is used to do fine grained partial rebuilds when running the server.
* A new and simpler tree document store which allows fast lookups and prefix-walking in all dimensions (e.g. language) concurrently.
* You can now configure an upper memory limit allowing for much larger data sets and/or running on lower specced PCs.
We have lifted the "no resources in sub folders" restriction for branch bundles (e.g. sections).
Memory Limit
* Hugos will, by default, set aside a quarter of the total system memory, but you can set this via the OS environment variable HUGO_MEMORYLIMIT (in gigabytes). This is backed by a partitioned LRU cache used throughout Hugo. A cache that gets dynamically resized in low memory situations, allowing Go's Garbage Collector to free the memory.

New Dependency Tracker: Hugo has had a rule based coarse grained approach to server rebuilds that has worked mostly pretty well, but there have been some surprises (e.g. stale content). This is now revamped with a new dependency tracker that can quickly calculate the delta given a changed resource (e.g. a content file, template, JS file etc.). This handles transitive relations, e.g. $page -> js.Build -> JS import, or $page1.Content -> render hook -> site.GetPage -> $page2.Title, or $page1.Content -> shortcode -> partial -> site.RegularPages -> $page2.Content -> shortcode ..., and should also handle changes to aggregated values (e.g. site.Lastmod) effectively.

This covers all of Hugo's API with 2 known exceptions (a list that may not be fully exhaustive):

Changes to files loaded with template func os.ReadFile may not be handled correctly. We recommend loading resources with resources.Get
Changes to Hugo objects (e.g. Page) passed in the template context to lang.Translate may not be detected correctly. We recommend having simple i18n templates without too much data context passed in other than simple types such as strings and numbers.
Note that the cachebuster configuration (when A changes then rebuild B) works well with the above, but we recommend that you revise that configuration, as it in most situations should not be needed. One example where it is still needed is with TailwindCSS and using changes to hugo_stats.json to trigger new CSS rebuilds.

Document Store: Previously, a little simplified, we split the document store (where we store pages and resources) in a tree per language. This worked pretty well, but the structure made some operations harder than they needed to be. We have now restructured it into one Radix tree for all languages. Internally the language is considered to be a dimension of that tree, and the tree can be viewed in all dimensions concurrently. This makes some operations re. language simpler (e.g. finding translations is just a slice range), but the idea is that it should also be relatively inexpensive to add more dimensions if needed (e.g. role).

Fixes #10169
Fixes #10364
Fixes #10482
Fixes #10630
Fixes #10656
Fixes #10694
Fixes #10918
Fixes #11262
Fixes #11439
Fixes #11453
Fixes #11457
Fixes #11466
Fixes #11540
Fixes #11551
Fixes #11556
Fixes #11654
Fixes #11661
Fixes #11663
Fixes #11664
Fixes #11669
Fixes #11671
Fixes #11807
Fixes #11808
Fixes #11809
Fixes #11815
Fixes #11840
Fixes #11853
Fixes #11860
Fixes #11883
Fixes #11904
Fixes #7388
Fixes #7425
Fixes #7436
Fixes #7544
Fixes #7882
Fixes #7960
Fixes #8255
Fixes #8307
Fixes #8863
Fixes #8927
Fixes #9192
Fixes #9324
2024-01-27 16:28:14 +01:00

251 lines
5.6 KiB
Go

// Copyright 2024 The Hugo Authors. 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 doctree
import (
"fmt"
"strings"
"sync"
radix "github.com/armon/go-radix"
)
var _ MutableTrees = MutableTrees{}
const (
LockTypeNone LockType = iota
LockTypeRead
LockTypeWrite
)
// AddEventListener adds an event listener to the tree.
// Note that the handler func may not add listeners.
func (ctx *WalkContext[T]) AddEventListener(event, path string, handler func(*Event[T])) {
if ctx.eventHandlers == nil {
ctx.eventHandlers = make(eventHandlers[T])
}
if ctx.eventHandlers[event] == nil {
ctx.eventHandlers[event] = make([]func(*Event[T]), 0)
}
// We want to match all above the path, so we need to exclude any similar named siblings.
if !strings.HasSuffix(path, "/") {
path += "/"
}
ctx.eventHandlers[event] = append(
ctx.eventHandlers[event], func(e *Event[T]) {
// Propagate events up the tree only.
if strings.HasPrefix(e.Path, path) {
handler(e)
}
},
)
}
// AddPostHook adds a post hook to the tree.
// This will be run after the tree has been walked.
func (ctx *WalkContext[T]) AddPostHook(handler func() error) {
ctx.HooksPost = append(ctx.HooksPost, handler)
}
func (ctx *WalkContext[T]) Data() *SimpleTree[any] {
ctx.dataInit.Do(func() {
ctx.data = &SimpleTree[any]{
tree: radix.New(),
}
})
return ctx.data
}
// SendEvent sends an event up the tree.
func (ctx *WalkContext[T]) SendEvent(event *Event[T]) {
ctx.events = append(ctx.events, event)
}
// StopPropagation stops the propagation of the event.
func (e *Event[T]) StopPropagation() {
e.stopPropagation = true
}
// ValidateKey returns an error if the key is not valid.
func ValidateKey(key string) error {
if key == "" {
// Root node.
return nil
}
if len(key) < 2 {
return fmt.Errorf("too short key: %q", key)
}
if key[0] != '/' {
return fmt.Errorf("key must start with '/': %q", key)
}
if key[len(key)-1] == '/' {
return fmt.Errorf("key must not end with '/': %q", key)
}
return nil
}
// Event is used to communicate events in the tree.
type Event[T any] struct {
Name string
Path string
Source T
stopPropagation bool
}
type LockType int
// MutableTree is a tree that can be modified.
type MutableTree interface {
Delete(key string)
DeleteAll(key string)
DeletePrefix(prefix string) int
DeletePrefixAll(prefix string) int
Lock(writable bool) (commit func())
CanLock() bool // Used for troubleshooting only.
}
// WalkableTree is a tree that can be walked.
type WalkableTree[T any] interface {
WalkPrefixRaw(prefix string, walker func(key string, value T) bool)
}
var _ WalkableTree[any] = (*WalkableTrees[any])(nil)
type WalkableTrees[T any] []WalkableTree[T]
func (t WalkableTrees[T]) WalkPrefixRaw(prefix string, walker func(key string, value T) bool) {
for _, tree := range t {
tree.WalkPrefixRaw(prefix, walker)
}
}
var _ MutableTree = MutableTrees(nil)
type MutableTrees []MutableTree
func (t MutableTrees) Delete(key string) {
for _, tree := range t {
tree.Delete(key)
}
}
func (t MutableTrees) DeleteAll(key string) {
for _, tree := range t {
tree.DeleteAll(key)
}
}
func (t MutableTrees) DeletePrefix(prefix string) int {
var count int
for _, tree := range t {
count += tree.DeletePrefix(prefix)
}
return count
}
func (t MutableTrees) DeletePrefixAll(prefix string) int {
var count int
for _, tree := range t {
count += tree.DeletePrefixAll(prefix)
}
return count
}
func (t MutableTrees) Lock(writable bool) (commit func()) {
commits := make([]func(), len(t))
for i, tree := range t {
commits[i] = tree.Lock(writable)
}
return func() {
for _, commit := range commits {
commit()
}
}
}
func (t MutableTrees) CanLock() bool {
for _, tree := range t {
if !tree.CanLock() {
return false
}
}
return true
}
// WalkContext is passed to the Walk callback.
type WalkContext[T any] struct {
data *SimpleTree[any]
dataInit sync.Once
eventHandlers eventHandlers[T]
events []*Event[T]
HooksPost []func() error
}
type eventHandlers[T any] map[string][]func(*Event[T])
func cleanKey(key string) string {
if key == "/" {
// The path to the home page is logically "/",
// but for technical reasons, it's stored as "".
// This allows us to treat the home page as a section,
// and a prefix search for "/" will return the home page's descendants.
return ""
}
return key
}
func (ctx *WalkContext[T]) HandleEvents() error {
for len(ctx.events) > 0 {
event := ctx.events[0]
ctx.events = ctx.events[1:]
// Loop the event handlers in reverse order so
// that events created by the handlers themselves will
// be picked up further up the tree.
for i := len(ctx.eventHandlers[event.Name]) - 1; i >= 0; i-- {
ctx.eventHandlers[event.Name][i](event)
if event.stopPropagation {
break
}
}
}
return nil
}
func (ctx *WalkContext[T]) HandleEventsAndHooks() error {
if err := ctx.HandleEvents(); err != nil {
return err
}
for _, hook := range ctx.HooksPost {
if err := hook(); err != nil {
return err
}
}
return nil
}
func mustValidateKey(key string) string {
if err := ValidateKey(key); err != nil {
panic(err)
}
return key
}