[performance] remove throttling timers (#1466)

* remove throttling timers, support setting retry-after, use retry-after in transport

* remove unused variables

* add throttling-retry-after to cmd flags

* update envparsing to include new throttling-retry-after

* update example config to include retry-after documentation

* also support retry-after formatted as date-time, ensure max backoff time

---------

Signed-off-by: kim <grufwub@gmail.com>
This commit is contained in:
kim 2023-02-10 20:16:01 +00:00 committed by GitHub
parent 6ac1dda96f
commit 70739d32cc
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
8 changed files with 98 additions and 62 deletions

View file

@ -203,10 +203,11 @@
// throttling
cpuMultiplier := config.GetAdvancedThrottlingMultiplier()
clThrottle := middleware.Throttle(cpuMultiplier) // client api
s2sThrottle := middleware.Throttle(cpuMultiplier) // server-to-server (AP)
fsThrottle := middleware.Throttle(cpuMultiplier) // fileserver / web templates
pkThrottle := middleware.Throttle(cpuMultiplier) // throttle public key endpoint separately
retryAfter := config.GetAdvancedThrottlingRetryAfter()
clThrottle := middleware.Throttle(cpuMultiplier, retryAfter) // client api
s2sThrottle := middleware.Throttle(cpuMultiplier, retryAfter) // server-to-server (AP)
fsThrottle := middleware.Throttle(cpuMultiplier, retryAfter) // fileserver / web templates
pkThrottle := middleware.Throttle(cpuMultiplier, retryAfter) // throttle public key endpoint separately
gzip := middleware.Gzip() // applied to all except fileserver

View file

@ -760,3 +760,10 @@ advanced-rate-limit-requests: 300
# Examples: [8, 4, 9, 0]
# Default: 8
advanced-throttling-multiplier: 8
# Duration. Time period to use as the "retry-after" header value in response to throttled requests.
# Minimum resolution is 1 second.
#
# Examples: [30s, 10s, 5s, 1m]
# Default: 30s
advanced-throttling-retry-after: "30s"

View file

@ -136,6 +136,7 @@ type Configuration struct {
AdvancedCookiesSamesite string `name:"advanced-cookies-samesite" usage:"'strict' or 'lax', see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie/SameSite"`
AdvancedRateLimitRequests int `name:"advanced-rate-limit-requests" usage:"Amount of HTTP requests to permit within a 5 minute window. 0 or less turns rate limiting off."`
AdvancedThrottlingMultiplier int `name:"advanced-throttling-multiplier" usage:"Multiplier to use per cpu for http request throttling. 0 or less turns throttling off."`
AdvancedThrottlingRetryAfter time.Duration `name:"advanced-throttling-retry-after" usage:"Retry-After duration response to send for throttled requests."`
// Cache configuration vars.
Cache CacheConfiguration `name:"cache"`

View file

@ -139,6 +139,7 @@ func (s *ConfigState) AddServerFlags(cmd *cobra.Command) {
cmd.Flags().String(AdvancedCookiesSamesiteFlag(), cfg.AdvancedCookiesSamesite, fieldtag("AdvancedCookiesSamesite", "usage"))
cmd.Flags().Int(AdvancedRateLimitRequestsFlag(), cfg.AdvancedRateLimitRequests, fieldtag("AdvancedRateLimitRequests", "usage"))
cmd.Flags().Int(AdvancedThrottlingMultiplierFlag(), cfg.AdvancedThrottlingMultiplier, fieldtag("AdvancedThrottlingMultiplier", "usage"))
cmd.Flags().Duration(AdvancedThrottlingRetryAfterFlag(), cfg.AdvancedThrottlingRetryAfter, fieldtag("AdvancedThrottlingRetryAfter", "usage"))
})
}

View file

@ -1999,6 +1999,31 @@ func GetAdvancedThrottlingMultiplier() int { return global.GetAdvancedThrottling
// SetAdvancedThrottlingMultiplier safely sets the value for global configuration 'AdvancedThrottlingMultiplier' field
func SetAdvancedThrottlingMultiplier(v int) { global.SetAdvancedThrottlingMultiplier(v) }
// GetAdvancedThrottlingRetryAfter safely fetches the Configuration value for state's 'AdvancedThrottlingRetryAfter' field
func (st *ConfigState) GetAdvancedThrottlingRetryAfter() (v time.Duration) {
st.mutex.Lock()
v = st.config.AdvancedThrottlingRetryAfter
st.mutex.Unlock()
return
}
// SetAdvancedThrottlingRetryAfter safely sets the Configuration value for state's 'AdvancedThrottlingRetryAfter' field
func (st *ConfigState) SetAdvancedThrottlingRetryAfter(v time.Duration) {
st.mutex.Lock()
defer st.mutex.Unlock()
st.config.AdvancedThrottlingRetryAfter = v
st.reloadToViper()
}
// AdvancedThrottlingRetryAfterFlag returns the flag name for the 'AdvancedThrottlingRetryAfter' field
func AdvancedThrottlingRetryAfterFlag() string { return "advanced-throttling-retry-after" }
// GetAdvancedThrottlingRetryAfter safely fetches the value for global configuration 'AdvancedThrottlingRetryAfter' field
func GetAdvancedThrottlingRetryAfter() time.Duration { return global.GetAdvancedThrottlingRetryAfter() }
// SetAdvancedThrottlingRetryAfter safely sets the value for global configuration 'AdvancedThrottlingRetryAfter' field
func SetAdvancedThrottlingRetryAfter(v time.Duration) { global.SetAdvancedThrottlingRetryAfter(v) }
// GetCacheGTSAccountMaxSize safely fetches the Configuration value for state's 'Cache.GTS.AccountMaxSize' field
func (st *ConfigState) GetCacheGTSAccountMaxSize() (v int) {
st.mutex.Lock()

View file

@ -29,17 +29,12 @@
import (
"net/http"
"runtime"
"strconv"
"time"
"github.com/gin-gonic/gin"
)
const (
errCapacityExceeded = "server capacity exceeded"
errTimedOut = "timed out while waiting for a pending request to complete"
errContextCanceled = "context canceled"
)
// token represents a request that is being processed.
type token struct{}
@ -73,11 +68,13 @@ type token struct{
//
// If the multiplier is <= 0, a noop middleware will be returned instead.
//
// RetryAfter determines the Retry-After header value to be sent to throttled requests.
//
// Useful links:
//
// - https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After
// - https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/503
func Throttle(cpuMultiplier int) gin.HandlerFunc {
func Throttle(cpuMultiplier int, retryAfter time.Duration) gin.HandlerFunc {
if cpuMultiplier <= 0 {
// throttling is disabled, return a noop middleware
return func(c *gin.Context) {}
@ -89,36 +86,24 @@ func Throttle(cpuMultiplier int) gin.HandlerFunc {
backlogChannelSize = limit + backlogLimit
tokens = make(chan token, limit)
backlogTokens = make(chan token, backlogChannelSize)
retryAfter = "30" // seconds
backlogDuration = 30 * time.Second
retryAfterStr = strconv.FormatUint(uint64(retryAfter/time.Second), 10)
)
// prefill token channels
for i := 0; i < limit; i++ {
tokens <- token{}
}
for i := 0; i < backlogChannelSize; i++ {
backlogTokens <- token{}
}
// bail instructs the requester to return after retryAfter seconds, returns a 503,
// and writes the given message into the "error" field of a returned json object
bail := func(c *gin.Context, msg string) {
c.Header("Retry-After", retryAfter)
c.JSON(http.StatusServiceUnavailable, gin.H{"error": msg})
c.Abort()
}
return func(c *gin.Context) {
// inside this select, the caller tries to get a backlog token
select {
case <-c.Request.Context().Done():
// request context has been canceled already
bail(c, errContextCanceled)
return
case btok := <-backlogTokens:
// take a backlog token and wait
timer := time.NewTimer(backlogDuration)
defer func() {
// when we're finished, return the backlog token to the bucket
backlogTokens <- btok
@ -127,16 +112,11 @@ func Throttle(cpuMultiplier int) gin.HandlerFunc {
// inside *this* select, the caller has a backlog token,
// and they're waiting for their turn to be processed
select {
case <-timer.C:
// waiting too long in the backlog
bail(c, errTimedOut)
case <-c.Request.Context().Done():
// the request context has been canceled already
timer.Stop()
bail(c, errContextCanceled)
return
case tok := <-tokens:
// the caller gets a token, so their request can now be processed
timer.Stop()
defer func() {
// whatever happens to the request, put the
// token back in the bucket when we're finished
@ -147,7 +127,9 @@ func Throttle(cpuMultiplier int) gin.HandlerFunc {
default:
// we don't have space in the backlog queue
bail(c, errCapacityExceeded)
c.Header("Retry-After", retryAfterStr)
c.JSON(http.StatusTooManyRequests, gin.H{"error": "server capacity exceeded"})
c.Abort()
}
}
}

View file

@ -27,6 +27,7 @@
"io"
"net/http"
"net/url"
"strconv"
"strings"
"sync"
"time"
@ -84,35 +85,36 @@ type transport struct {
}
// GET will perform given http request using transport client, retrying on certain preset errors, or if status code is among retryOn.
func (t *transport) GET(r *http.Request, retryOn ...int) (*http.Response, error) {
func (t *transport) GET(r *http.Request) (*http.Response, error) {
if r.Method != http.MethodGet {
return nil, errors.New("must be GET request")
}
return t.do(r, func(r *http.Request) error {
return t.signGET(r)
}, retryOn...)
})
}
// POST will perform given http request using transport client, retrying on certain preset errors, or if status code is among retryOn.
func (t *transport) POST(r *http.Request, body []byte, retryOn ...int) (*http.Response, error) {
func (t *transport) POST(r *http.Request, body []byte) (*http.Response, error) {
if r.Method != http.MethodPost {
return nil, errors.New("must be POST request")
}
return t.do(r, func(r *http.Request) error {
return t.signPOST(r, body)
}, retryOn...)
})
}
func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryOn ...int) (*http.Response, error) {
const maxRetries = 5
func (t *transport) do(r *http.Request, signer func(*http.Request) error) (*http.Response, error) {
const (
// max no. attempts
maxRetries = 5
var (
// Initial backoff duration
backoff = 2 * time.Second
// starting backoff duration.
baseBackoff = 2 * time.Second
)
// Get request hostname
host = r.URL.Hostname()
)
host := r.URL.Hostname()
// Check if recently reached max retries for this host
// so we don't need to bother reattempting it. The only
@ -137,6 +139,8 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryO
r.Header.Set("User-Agent", t.controller.userAgent)
for i := 0; i < maxRetries; i++ {
var backoff time.Duration
// Reset signing header fields
now := t.controller.clock.Now().UTC()
r.Header.Set("Date", now.Format("Mon, 02 Jan 2006 15:04:05")+" GMT")
@ -152,18 +156,35 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryO
// Attempt to perform request
rsp, err := t.controller.client.Do(r)
if err == nil { //nolint shutup linter
if err == nil { //nolint:gocritic
// TooManyRequest means we need to slow
// down and retry our request. Codes over
// 500 generally indicate temp. outages.
if code := rsp.StatusCode; code < 500 &&
code != http.StatusTooManyRequests &&
!containsInt(retryOn, rsp.StatusCode) {
code != http.StatusTooManyRequests {
return rsp, nil
}
// Generate error from status code for logging
err = errors.New(`http response "` + rsp.Status + `"`)
// Search for a provided "Retry-After" header value.
if after := rsp.Header.Get("Retry-After"); after != "" {
if u, _ := strconv.ParseUint(after, 10, 32); u != 0 {
// An integer number of backoff seconds was provided.
backoff = time.Duration(u) * time.Second
} else if at, _ := http.ParseTime(after); !at.Before(now) {
// An HTTP formatted future date-time was provided.
backoff = at.Sub(now)
}
// Don't let their provided backoff exceed our max.
if max := baseBackoff * maxRetries; backoff > max {
backoff = max
}
}
} else if errorsv2.Is(err,
context.DeadlineExceeded,
context.Canceled,
@ -179,11 +200,18 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryO
} else if errors.As(err, &x509.UnknownAuthorityError{}) {
// Unknown authority errors we do NOT recover from
return nil, err
} else if fastFail {
}
if fastFail {
// on fast-fail, don't bother backoff/retry
return nil, fmt.Errorf("%w (fast fail)", err)
}
if backoff == 0 {
// No retry-after found, set our predefined backoff.
backoff = time.Duration(i) * baseBackoff
}
l.Errorf("backing off for %s after http request error: %v", backoff.String(), err)
select {
@ -238,13 +266,3 @@ func (t *transport) safesign(sign func()) {
// Perform signing
sign()
}
// containsInt checks if slice contains check.
func containsInt(slice []int, check int) bool {
for _, i := range slice {
if i == check {
return true
}
}
return false
}

View file

@ -2,7 +2,7 @@
set -eu
EXPECT='{"account-domain":"peepee","accounts-allow-custom-css":true,"accounts-approval-required":false,"accounts-reason-required":false,"accounts-registration-open":true,"advanced-cookies-samesite":"strict","advanced-rate-limit-requests":6969,"advanced-throttling-multiplier":-1,"application-name":"gts","bind-address":"127.0.0.1","cache":{"gts":{"account-max-size":99,"account-sweep-freq":1000000000,"account-ttl":10800000000000,"block-max-size":100,"block-sweep-freq":10000000000,"block-ttl":300000000000,"domain-block-max-size":1000,"domain-block-sweep-freq":60000000000,"domain-block-ttl":86400000000000,"emoji-category-max-size":100,"emoji-category-sweep-freq":10000000000,"emoji-category-ttl":300000000000,"emoji-max-size":500,"emoji-sweep-freq":10000000000,"emoji-ttl":300000000000,"mention-max-size":500,"mention-sweep-freq":10000000000,"mention-ttl":300000000000,"notification-max-size":500,"notification-sweep-freq":10000000000,"notification-ttl":300000000000,"report-max-size":100,"report-sweep-freq":10000000000,"report-ttl":300000000000,"status-max-size":500,"status-sweep-freq":10000000000,"status-ttl":300000000000,"tombstone-max-size":100,"tombstone-sweep-freq":10000000000,"tombstone-ttl":300000000000,"user-max-size":100,"user-sweep-freq":10000000000,"user-ttl":300000000000}},"config-path":"internal/config/testdata/test.yaml","db-address":":memory:","db-database":"gotosocial_prod","db-max-open-conns-multiplier":3,"db-password":"hunter2","db-port":6969,"db-sqlite-busy-timeout":1000000000,"db-sqlite-cache-size":0,"db-sqlite-journal-mode":"DELETE","db-sqlite-synchronous":"FULL","db-tls-ca-cert":"","db-tls-mode":"disable","db-type":"sqlite","db-user":"sex-haver","dry-run":false,"email":"","host":"example.com","instance-deliver-to-shared-inboxes":false,"instance-expose-peers":true,"instance-expose-public-timeline":true,"instance-expose-suspended":true,"instance-expose-suspended-web":true,"landing-page-user":"admin","letsencrypt-cert-dir":"/gotosocial/storage/certs","letsencrypt-email-address":"","letsencrypt-enabled":true,"letsencrypt-port":80,"log-db-queries":true,"log-level":"info","media-description-max-chars":5000,"media-description-min-chars":69,"media-emoji-local-max-size":420,"media-emoji-remote-max-size":420,"media-image-max-size":420,"media-remote-cache-days":30,"media-video-max-size":420,"oidc-client-id":"1234","oidc-client-secret":"shhhh its a secret","oidc-enabled":true,"oidc-idp-name":"sex-haver","oidc-issuer":"whoknows","oidc-link-existing":true,"oidc-scopes":["read","write"],"oidc-skip-verification":true,"password":"","path":"","port":6969,"protocol":"http","smtp-from":"queen.rip.in.piss@terfisland.org","smtp-host":"example.com","smtp-password":"hunter2","smtp-port":4269,"smtp-username":"sex-haver","software-version":"","statuses-cw-max-chars":420,"statuses-max-chars":69,"statuses-media-max-files":1,"statuses-poll-max-options":1,"statuses-poll-option-max-chars":50,"storage-backend":"local","storage-local-base-path":"/root/store","storage-s3-access-key":"minio","storage-s3-bucket":"gts","storage-s3-endpoint":"localhost:9000","storage-s3-proxy":true,"storage-s3-secret-key":"miniostorage","storage-s3-use-ssl":false,"syslog-address":"127.0.0.1:6969","syslog-enabled":true,"syslog-protocol":"udp","trusted-proxies":["127.0.0.1/32","docker.host.local"],"username":"","web-asset-base-dir":"/root","web-template-base-dir":"/root"}'
EXPECT='{"account-domain":"peepee","accounts-allow-custom-css":true,"accounts-approval-required":false,"accounts-reason-required":false,"accounts-registration-open":true,"advanced-cookies-samesite":"strict","advanced-rate-limit-requests":6969,"advanced-throttling-multiplier":-1,"advanced-throttling-retry-after":10000000000,"application-name":"gts","bind-address":"127.0.0.1","cache":{"gts":{"account-max-size":99,"account-sweep-freq":1000000000,"account-ttl":10800000000000,"block-max-size":100,"block-sweep-freq":10000000000,"block-ttl":300000000000,"domain-block-max-size":1000,"domain-block-sweep-freq":60000000000,"domain-block-ttl":86400000000000,"emoji-category-max-size":100,"emoji-category-sweep-freq":10000000000,"emoji-category-ttl":300000000000,"emoji-max-size":500,"emoji-sweep-freq":10000000000,"emoji-ttl":300000000000,"mention-max-size":500,"mention-sweep-freq":10000000000,"mention-ttl":300000000000,"notification-max-size":500,"notification-sweep-freq":10000000000,"notification-ttl":300000000000,"report-max-size":100,"report-sweep-freq":10000000000,"report-ttl":300000000000,"status-max-size":500,"status-sweep-freq":10000000000,"status-ttl":300000000000,"tombstone-max-size":100,"tombstone-sweep-freq":10000000000,"tombstone-ttl":300000000000,"user-max-size":100,"user-sweep-freq":10000000000,"user-ttl":300000000000}},"config-path":"internal/config/testdata/test.yaml","db-address":":memory:","db-database":"gotosocial_prod","db-max-open-conns-multiplier":3,"db-password":"hunter2","db-port":6969,"db-sqlite-busy-timeout":1000000000,"db-sqlite-cache-size":0,"db-sqlite-journal-mode":"DELETE","db-sqlite-synchronous":"FULL","db-tls-ca-cert":"","db-tls-mode":"disable","db-type":"sqlite","db-user":"sex-haver","dry-run":false,"email":"","host":"example.com","instance-deliver-to-shared-inboxes":false,"instance-expose-peers":true,"instance-expose-public-timeline":true,"instance-expose-suspended":true,"instance-expose-suspended-web":true,"landing-page-user":"admin","letsencrypt-cert-dir":"/gotosocial/storage/certs","letsencrypt-email-address":"","letsencrypt-enabled":true,"letsencrypt-port":80,"log-db-queries":true,"log-level":"info","media-description-max-chars":5000,"media-description-min-chars":69,"media-emoji-local-max-size":420,"media-emoji-remote-max-size":420,"media-image-max-size":420,"media-remote-cache-days":30,"media-video-max-size":420,"oidc-client-id":"1234","oidc-client-secret":"shhhh its a secret","oidc-enabled":true,"oidc-idp-name":"sex-haver","oidc-issuer":"whoknows","oidc-link-existing":true,"oidc-scopes":["read","write"],"oidc-skip-verification":true,"password":"","path":"","port":6969,"protocol":"http","smtp-from":"queen.rip.in.piss@terfisland.org","smtp-host":"example.com","smtp-password":"hunter2","smtp-port":4269,"smtp-username":"sex-haver","software-version":"","statuses-cw-max-chars":420,"statuses-max-chars":69,"statuses-media-max-files":1,"statuses-poll-max-options":1,"statuses-poll-option-max-chars":50,"storage-backend":"local","storage-local-base-path":"/root/store","storage-s3-access-key":"minio","storage-s3-bucket":"gts","storage-s3-endpoint":"localhost:9000","storage-s3-proxy":true,"storage-s3-secret-key":"miniostorage","storage-s3-use-ssl":false,"syslog-address":"127.0.0.1:6969","syslog-enabled":true,"syslog-protocol":"udp","trusted-proxies":["127.0.0.1/32","docker.host.local"],"username":"","web-asset-base-dir":"/root","web-template-base-dir":"/root"}'
# Set all the environment variables to
# ensure that these are parsed without panic
@ -83,6 +83,7 @@ GTS_SYSLOG_ADDRESS='127.0.0.1:6969' \
GTS_ADVANCED_COOKIES_SAMESITE='strict' \
GTS_ADVANCED_RATE_LIMIT_REQUESTS=6969 \
GTS_ADVANCED_THROTTLING_MULTIPLIER=-1 \
GTS_ADVANCED_THROTTLING_RETRY_AFTER='10s' \
go run ./cmd/gotosocial/... --config-path internal/config/testdata/test.yaml debug config)
OUTPUT_OUT=$(mktemp)