[feature] simpler cache size configuration (#2051)

* add automatic cache max size generation based on ratios of a singular fixed memory target

Signed-off-by: kim <grufwub@gmail.com>

* remove now-unused cache max-size config variables

Signed-off-by: kim <grufwub@gmail.com>

* slight ratio tweak

Signed-off-by: kim <grufwub@gmail.com>

* remove unused visibility config var

Signed-off-by: kim <grufwub@gmail.com>

* add secret little ratio config trick

Signed-off-by: kim <grufwub@gmail.com>

* fixed a word

Signed-off-by: kim <grufwub@gmail.com>

* update cache library to remove use of TTL in result caches + slice cache

Signed-off-by: kim <grufwub@gmail.com>

* update other cache usages to use correct interface

Signed-off-by: kim <grufwub@gmail.com>

* update example config to explain the cache memory target

Signed-off-by: kim <grufwub@gmail.com>

* update env parsing test with new config values

Signed-off-by: kim <grufwub@gmail.com>

* do some ratio twiddling

Signed-off-by: kim <grufwub@gmail.com>

* add missing header

* update envparsing with latest defaults

Signed-off-by: kim <grufwub@gmail.com>

* update size calculations to take into account result cache, simple cache and extra map overheads

Signed-off-by: kim <grufwub@gmail.com>

* tweak the ratios some more

Signed-off-by: kim <grufwub@gmail.com>

* more nan rampaging

Signed-off-by: kim <grufwub@gmail.com>

* fix envparsing script

Signed-off-by: kim <grufwub@gmail.com>

* update cache library, add sweep function to keep caches trim

Signed-off-by: kim <grufwub@gmail.com>

* sweep caches once a minute

Signed-off-by: kim <grufwub@gmail.com>

* add a regular job to sweep caches and keep under 80% utilisation

Signed-off-by: kim <grufwub@gmail.com>

* remove dead code

Signed-off-by: kim <grufwub@gmail.com>

* add new size library used to libraries section of readme

Signed-off-by: kim <grufwub@gmail.com>

* add better explanations for the mem-ratio numbers

Signed-off-by: kim <grufwub@gmail.com>

* update go-cache

Signed-off-by: kim <grufwub@gmail.com>

* library version bump

Signed-off-by: kim <grufwub@gmail.com>

* update cache.result{} size model estimation

Signed-off-by: kim <grufwub@gmail.com>

---------

Signed-off-by: kim <grufwub@gmail.com>

1 files changed, 501 insertions, 0 deletions

diff --git a/internal/cache/size.go b/internal/cache/size.go
new file mode 100644
index 000000000..56524575b
--- /dev/null
+++ b/internal/cache/size.go
@@ -0,0 +1,501 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cache
+
+import (
+	"crypto/rsa"
+	"time"
+	"unsafe"
+
+	"codeberg.org/gruf/go-cache/v3/simple"
+	"github.com/DmitriyVTitov/size"
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+const (
+	// example data values.
+	exampleID   = id.Highest
+	exampleURI  = "https://social.bbc/users/ItsMePrinceCharlesInit"
+	exampleText = `
+oh no me nan's gone and done it :shocked:
+	
+she fuckin killed the king :regicide:
+
+nan what have you done :shocked:
+
+no nan put down the knife, don't go after the landlords next! :knife:
+
+you'll make society more equitable for all if you're not careful! :hammer_sickle:
+
+#JustNanProblems #WhatWillSheDoNext #MaybeItWasntSuchABadThingAfterAll
+`
+
+	exampleTextSmall = "Small problem lads, me nan's gone on a bit of a rampage"
+	exampleUsername  = "@SexHaver1969"
+
+	// ID string size in memory (is always 26 char ULID).
+	sizeofIDStr = unsafe.Sizeof(exampleID)
+
+	// URI string size in memory (use some random example URI).
+	sizeofURIStr = unsafe.Sizeof(exampleURI)
+
+	// ID slice size in memory (using some estimate of length = 250).
+	sizeofIDSlice = unsafe.Sizeof([]string{}) + 250*sizeofIDStr
+
+	// result cache key size estimate which is tricky. it can
+	// be a serialized string of almost any type, so we pick a
+	// nice serialized key size on the upper end of normal.
+	sizeofResultKey = 2 * sizeofIDStr
+)
+
+// calculateSliceCacheMax calculates the maximum capacity for a slice cache with given individual ratio.
+func calculateSliceCacheMax(ratio float64) int {
+	return calculateCacheMax(sizeofIDStr, sizeofIDSlice, ratio)
+}
+
+// calculateResultCacheMax calculates the maximum cache capacity for a result
+// cache's individual ratio number, and the size of the struct model in memory.
+func calculateResultCacheMax(structSz uintptr, ratio float64) int {
+	// Estimate a worse-case scenario of extra lookup hash maps,
+	// where lookups are the no. "keys" each result can be found under
+	const lookups = 10
+
+	// Calculate the extra cache lookup map overheads.
+	totalLookupKeySz := uintptr(lookups) * sizeofResultKey
+	totalLookupValSz := uintptr(lookups) * unsafe.Sizeof(uint64(0))
+
+	// Primary cache sizes.
+	pkeySz := unsafe.Sizeof(uint64(0))
+	pvalSz := structSz
+
+	// The result cache wraps each struct result in a wrapping
+	// struct with further information, and possible error. This
+	// also needs to be taken into account when calculating value.
+	const resultValueOverhead = unsafe.Sizeof(&struct {
+		_ int64
+		_ []any
+		_ any
+		_ error
+	}{})
+
+	return calculateCacheMax(
+		pkeySz+totalLookupKeySz,
+		pvalSz+totalLookupValSz+resultValueOverhead,
+		ratio,
+	)
+}
+
+// calculateCacheMax calculates the maximum cache capacity for a cache's
+// individual ratio number, and key + value object sizes in memory.
+func calculateCacheMax(keySz, valSz uintptr, ratio float64) int {
+	if ratio < 0 {
+		// Negative ratios are a secret little trick
+		// to manually set the cache capacity sizes.
+		return int(-1 * ratio)
+	}
+
+	// see: https://golang.org/src/runtime/map.go
+	const emptyBucketOverhead = 10.79
+
+	// This takes into account (roughly) that the underlying simple cache library wraps
+	// elements within a simple.Entry{}, and the ordered map wraps each in a linked list elem.
+	const cacheElemOverhead = unsafe.Sizeof(simple.Entry{}) + unsafe.Sizeof(struct {
+		key, value interface{}
+		next, prev uintptr
+	}{})
+
+	// The inputted memory ratio does not take into account the
+	// total of all ratios, so divide it here to get perc. ratio.
+	totalRatio := ratio / totalOfRatios()
+
+	// TODO: we should also further weight this ratio depending
+	// on the combined keySz + valSz as a ratio of all available
+	// cache model memories. otherwise you can end up with a
+	// low-ratio cache of tiny models with larger capacity than
+	// a high-ratio cache of large models.
+
+	// Get max available cache memory, calculating max for
+	// this cache by multiplying by this cache's mem ratio.
+	maxMem := config.GetCacheMemoryTarget()
+	fMaxMem := float64(maxMem) * totalRatio
+
+	// Cast to useable types.
+	fKeySz := float64(keySz)
+	fValSz := float64(valSz)
+
+	// Calculated using the internal cache map size:
+	// (($keysz + $valsz) * $len) + ($len * $allOverheads) = $memSz
+	return int(fMaxMem / (fKeySz + fValSz + emptyBucketOverhead + float64(cacheElemOverhead)))
+}
+
+// totalOfRatios returns the total of all cache ratios added together.
+func totalOfRatios() float64 {
+	// NOTE: this is not performant calculating
+	// this every damn time (mainly the mutex unlocks
+	// required to access each config var). fortunately
+	// we only do this on init so fuck it :D
+	return 0 +
+		config.GetCacheAccountMemRatio() +
+		config.GetCacheAccountNoteMemRatio() +
+		config.GetCacheBlockMemRatio() +
+		config.GetCacheBlockIDsMemRatio() +
+		config.GetCacheEmojiMemRatio() +
+		config.GetCacheEmojiCategoryMemRatio() +
+		config.GetCacheFollowMemRatio() +
+		config.GetCacheFollowIDsMemRatio() +
+		config.GetCacheFollowRequestMemRatio() +
+		config.GetCacheFollowRequestIDsMemRatio() +
+		config.GetCacheInstanceMemRatio() +
+		config.GetCacheListMemRatio() +
+		config.GetCacheListEntryMemRatio() +
+		config.GetCacheMarkerMemRatio() +
+		config.GetCacheMediaMemRatio() +
+		config.GetCacheMentionMemRatio() +
+		config.GetCacheNotificationMemRatio() +
+		config.GetCacheReportMemRatio() +
+		config.GetCacheStatusMemRatio() +
+		config.GetCacheStatusFaveMemRatio() +
+		config.GetCacheTagMemRatio() +
+		config.GetCacheTombstoneMemRatio() +
+		config.GetCacheUserMemRatio() +
+		config.GetCacheWebfingerMemRatio() +
+		config.GetCacheVisibilityMemRatio()
+}
+
+func sizeofAccount() uintptr {
+	return uintptr(size.Of(&gtsmodel.Account{
+		ID:                      exampleID,
+		Username:                exampleUsername,
+		AvatarMediaAttachmentID: exampleID,
+		HeaderMediaAttachmentID: exampleID,
+		DisplayName:             exampleUsername,
+		Note:                    exampleText,
+		NoteRaw:                 exampleText,
+		Memorial:                func() *bool { ok := false; return &ok }(),
+		CreatedAt:               time.Now(),
+		UpdatedAt:               time.Now(),
+		FetchedAt:               time.Now(),
+		Bot:                     func() *bool { ok := true; return &ok }(),
+		Locked:                  func() *bool { ok := true; return &ok }(),
+		Discoverable:            func() *bool { ok := false; return &ok }(),
+		Privacy:                 gtsmodel.VisibilityFollowersOnly,
+		Sensitive:               func() *bool { ok := true; return &ok }(),
+		Language:                "fr",
+		URI:                     exampleURI,
+		URL:                     exampleURI,
+		InboxURI:                exampleURI,
+		OutboxURI:               exampleURI,
+		FollowersURI:            exampleURI,
+		FollowingURI:            exampleURI,
+		FeaturedCollectionURI:   exampleURI,
+		ActorType:               ap.ActorPerson,
+		PrivateKey:              &rsa.PrivateKey{},
+		PublicKey:               &rsa.PublicKey{},
+		PublicKeyURI:            exampleURI,
+		SensitizedAt:            time.Time{},
+		SilencedAt:              time.Now(),
+		SuspendedAt:             time.Now(),
+		HideCollections:         func() *bool { ok := true; return &ok }(),
+		SuspensionOrigin:        "",
+		EnableRSS:               func() *bool { ok := true; return &ok }(),
+	}))
+}
+
+func sizeofAccountNote() uintptr {
+	return uintptr(size.Of(&gtsmodel.AccountNote{
+		ID:              exampleID,
+		AccountID:       exampleID,
+		TargetAccountID: exampleID,
+		Comment:         exampleTextSmall,
+	}))
+}
+
+func sizeofBlock() uintptr {
+	return uintptr(size.Of(&gtsmodel.Block{
+		ID:              exampleID,
+		CreatedAt:       time.Now(),
+		UpdatedAt:       time.Now(),
+		URI:             exampleURI,
+		AccountID:       exampleID,
+		TargetAccountID: exampleID,
+	}))
+}
+
+func sizeofEmoji() uintptr {
+	return uintptr(size.Of(&gtsmodel.Emoji{
+		ID:                     exampleID,
+		Shortcode:              exampleTextSmall,
+		Domain:                 exampleURI,
+		CreatedAt:              time.Now(),
+		UpdatedAt:              time.Now(),
+		ImageRemoteURL:         exampleURI,
+		ImageStaticRemoteURL:   exampleURI,
+		ImageURL:               exampleURI,
+		ImagePath:              exampleURI,
+		ImageStaticURL:         exampleURI,
+		ImageStaticPath:        exampleURI,
+		ImageContentType:       "image/png",
+		ImageStaticContentType: "image/png",
+		ImageUpdatedAt:         time.Now(),
+		Disabled:               func() *bool { ok := false; return &ok }(),
+		URI:                    "http://localhost:8080/emoji/01F8MH9H8E4VG3KDYJR9EGPXCQ",
+		VisibleInPicker:        func() *bool { ok := true; return &ok }(),
+		CategoryID:             "01GGQ8V4993XK67B2JB396YFB7",
+		Cached:                 func() *bool { ok := true; return &ok }(),
+	}))
+}
+
+func sizeofEmojiCategory() uintptr {
+	return uintptr(size.Of(&gtsmodel.EmojiCategory{
+		ID:        exampleID,
+		Name:      exampleUsername,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}))
+}
+
+func sizeofFollow() uintptr {
+	return uintptr(size.Of(&gtsmodel.Follow{
+		ID:              exampleID,
+		CreatedAt:       time.Now(),
+		UpdatedAt:       time.Now(),
+		AccountID:       exampleID,
+		TargetAccountID: exampleID,
+		ShowReblogs:     func() *bool { ok := true; return &ok }(),
+		URI:             exampleURI,
+		Notify:          func() *bool { ok := false; return &ok }(),
+	}))
+}
+
+func sizeofFollowRequest() uintptr {
+	return uintptr(size.Of(&gtsmodel.FollowRequest{
+		ID:              exampleID,
+		CreatedAt:       time.Now(),
+		UpdatedAt:       time.Now(),
+		AccountID:       exampleID,
+		TargetAccountID: exampleID,
+		ShowReblogs:     func() *bool { ok := true; return &ok }(),
+		URI:             exampleURI,
+		Notify:          func() *bool { ok := false; return &ok }(),
+	}))
+}
+
+func sizeofInstance() uintptr {
+	return uintptr(size.Of(&gtsmodel.Instance{
+		ID:                     exampleID,
+		CreatedAt:              time.Now(),
+		UpdatedAt:              time.Now(),
+		Domain:                 exampleURI,
+		URI:                    exampleURI,
+		Title:                  exampleTextSmall,
+		ShortDescription:       exampleText,
+		Description:            exampleText,
+		ContactEmail:           exampleUsername,
+		ContactAccountUsername: exampleUsername,
+		ContactAccountID:       exampleID,
+	}))
+}
+
+func sizeofList() uintptr {
+	return uintptr(size.Of(&gtsmodel.List{
+		ID:            exampleID,
+		CreatedAt:     time.Now(),
+		UpdatedAt:     time.Now(),
+		Title:         exampleTextSmall,
+		AccountID:     exampleID,
+		RepliesPolicy: gtsmodel.RepliesPolicyFollowed,
+	}))
+}
+
+func sizeofListEntry() uintptr {
+	return uintptr(size.Of(&gtsmodel.ListEntry{
+		ID:        exampleID,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+		ListID:    exampleID,
+		FollowID:  exampleID,
+	}))
+}
+
+func sizeofMarker() uintptr {
+	return uintptr(size.Of(&gtsmodel.Marker{
+		AccountID:  exampleID,
+		Name:       gtsmodel.MarkerNameHome,
+		UpdatedAt:  time.Now(),
+		Version:    0,
+		LastReadID: exampleID,
+	}))
+}
+
+func sizeofMedia() uintptr {
+	return uintptr(size.Of(&gtsmodel.MediaAttachment{
+		ID:                exampleID,
+		StatusID:          exampleID,
+		URL:               exampleURI,
+		RemoteURL:         exampleURI,
+		CreatedAt:         time.Now(),
+		UpdatedAt:         time.Now(),
+		Type:              gtsmodel.FileTypeImage,
+		AccountID:         exampleID,
+		Description:       exampleText,
+		ScheduledStatusID: exampleID,
+		Blurhash:          exampleTextSmall,
+		File: gtsmodel.File{
+			Path:        exampleURI,
+			ContentType: "image/jpeg",
+			UpdatedAt:   time.Now(),
+		},
+		Thumbnail: gtsmodel.Thumbnail{
+			Path:        exampleURI,
+			ContentType: "image/jpeg",
+			UpdatedAt:   time.Now(),
+			URL:         exampleURI,
+			RemoteURL:   exampleURI,
+		},
+		Avatar: func() *bool { ok := false; return &ok }(),
+		Header: func() *bool { ok := false; return &ok }(),
+		Cached: func() *bool { ok := true; return &ok }(),
+	}))
+}
+
+func sizeofMention() uintptr {
+	return uintptr(size.Of(&gtsmodel.Mention{
+		ID:               exampleURI,
+		StatusID:         exampleURI,
+		CreatedAt:        time.Now(),
+		UpdatedAt:        time.Now(),
+		OriginAccountID:  exampleURI,
+		OriginAccountURI: exampleURI,
+		TargetAccountID:  exampleID,
+		NameString:       exampleUsername,
+		TargetAccountURI: exampleURI,
+		TargetAccountURL: exampleURI,
+	}))
+}
+
+func sizeofNotification() uintptr {
+	return uintptr(size.Of(&gtsmodel.Notification{
+		ID:               exampleID,
+		NotificationType: gtsmodel.NotificationFave,
+		CreatedAt:        time.Now(),
+		TargetAccountID:  exampleID,
+		OriginAccountID:  exampleID,
+		StatusID:         exampleID,
+		Read:             func() *bool { ok := false; return &ok }(),
+	}))
+}
+
+func sizeofReport() uintptr {
+	return uintptr(size.Of(&gtsmodel.Report{
+		ID:                     exampleID,
+		CreatedAt:              time.Now(),
+		UpdatedAt:              time.Now(),
+		URI:                    exampleURI,
+		AccountID:              exampleID,
+		TargetAccountID:        exampleID,
+		Comment:                exampleText,
+		StatusIDs:              []string{exampleID, exampleID, exampleID},
+		Forwarded:              func() *bool { ok := true; return &ok }(),
+		ActionTaken:            exampleText,
+		ActionTakenAt:          time.Now(),
+		ActionTakenByAccountID: exampleID,
+	}))
+}
+
+func sizeofStatus() uintptr {
+	return uintptr(size.Of(&gtsmodel.Status{
+		ID:                       exampleURI,
+		URI:                      exampleURI,
+		URL:                      exampleURI,
+		Content:                  exampleText,
+		Text:                     exampleText,
+		AttachmentIDs:            []string{exampleID, exampleID, exampleID},
+		TagIDs:                   []string{exampleID, exampleID, exampleID},
+		MentionIDs:               []string{},
+		EmojiIDs:                 []string{exampleID, exampleID, exampleID},
+		CreatedAt:                time.Now(),
+		UpdatedAt:                time.Now(),
+		FetchedAt:                time.Now(),
+		Local:                    func() *bool { ok := false; return &ok }(),
+		AccountURI:               exampleURI,
+		AccountID:                exampleID,
+		InReplyToID:              exampleID,
+		InReplyToURI:             exampleURI,
+		InReplyToAccountID:       exampleID,
+		BoostOfID:                exampleID,
+		BoostOfAccountID:         exampleID,
+		ContentWarning:           exampleUsername, // similar length
+		Visibility:               gtsmodel.VisibilityPublic,
+		Sensitive:                func() *bool { ok := false; return &ok }(),
+		Language:                 "en",
+		CreatedWithApplicationID: exampleID,
+		Federated:                func() *bool { ok := true; return &ok }(),
+		Boostable:                func() *bool { ok := true; return &ok }(),
+		Replyable:                func() *bool { ok := true; return &ok }(),
+		Likeable:                 func() *bool { ok := true; return &ok }(),
+		ActivityStreamsType:      ap.ObjectNote,
+	}))
+}
+
+func sizeofStatusFave() uintptr {
+	return uintptr(size.Of(&gtsmodel.StatusFave{
+		ID:              exampleID,
+		CreatedAt:       time.Now(),
+		AccountID:       exampleID,
+		TargetAccountID: exampleID,
+		StatusID:        exampleID,
+		URI:             exampleURI,
+	}))
+}
+
+func sizeofTag() uintptr {
+	return uintptr(size.Of(&gtsmodel.Tag{
+		ID:        exampleID,
+		Name:      exampleUsername,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+		Useable:   func() *bool { ok := true; return &ok }(),
+		Listable:  func() *bool { ok := true; return &ok }(),
+	}))
+}
+
+func sizeofTombstone() uintptr {
+	return uintptr(size.Of(&gtsmodel.Tombstone{
+		ID:        exampleID,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+		Domain:    exampleUsername,
+		URI:       exampleURI,
+	}))
+}
+
+func sizeofVisibility() uintptr {
+	return uintptr(size.Of(&CachedVisibility{
+		ItemID:      exampleID,
+		RequesterID: exampleID,
+		Type:        VisibilityTypeAccount,
+		Value:       false,
+	}))
+}
+
+func sizeofUser() uintptr {
+	return uintptr(size.Of(&gtsmodel.User{}))
+}