multi-acc rate limited lookin pretty good~

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/go-echarts/go-echarts/v2 v2.3.1
 	github.com/guptarohit/asciigraph v0.7.3
 	golang.org/x/crypto v0.38.0
+	golang.org/x/time v0.11.0
 )
 
 require (

go.sum

@@ -14,5 +14,7 @@ golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
 golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/term v0.32.0 h1:DR4lr0TjUs3epypdhTOkMmuF5CDFJ/8pOnbzMZPQ7bg=
 golang.org/x/term v0.32.0/go.mod h1:uZG1FhGx848Sqfsq4/DlJr3xGGsYMu/L5GW4abiaEPQ=
+golang.org/x/time v0.11.0 h1:/bpjEDfN9tkoN/ryeYHnv5hcMlc8ncjMcM4XBk5NWV0=
+golang.org/x/time v0.11.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
 gopkg.in/yaml.v3 v3.0.0 h1:hjy8E9ON/egN1tAYqKb61G10WtihqetD4sz2H+8nIeA=
 gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

src/bank/teller/teller.go

@@ -7,11 +7,14 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"strings"
 	"time"
 
 	"gogs.inhome.blapointe.com/ana-ledger/src/bank"
+
+	"golang.org/x/time/rate"
 )
 
 type Client struct {
@@ -55,7 +58,14 @@ func (c Client) Transactions(ctx context.Context, a bank.Account) ([]bank.Transa
 	return result, err
 }
 
+var limiter = rate.NewLimiter(0.1, 1)
+
 func (c Client) get(ctx context.Context, url, token string, ptr interface{}) error {
+	if err := limiter.Wait(ctx); err != nil {
+		return err
+	}
+
+	log.Printf("Teller.Get(%s, %s)", url, token)
 	httpc := &http.Client{
 		Timeout: time.Second,
 		Transport: &http.Transport{

src/bank/teller/token.txt

@@ -1 +1,3 @@
 token_2utqstwpn3pxwgvyno56hqdehq
+token_vr6dnzvfv7c24wuxtmnnzyiqbm
+token_r4pbocuwhxoorjiag67rq4zen4

src/bank/types.go

@@ -13,7 +13,7 @@ type Account struct {
 	} `json:"institution"`
 	Name    string `json:"last_four"`
 	Account string `json:"id"`
-	Token   string `json:"-"`
+	Token   string `json:"__token"`
 }
 
 type Transaction struct {

vendor/golang.org/x/time/LICENSE

@@ -0,0 +1,27 @@
+Copyright 2009 The Go Authors.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google LLC nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/golang.org/x/time/PATENTS

@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.

vendor/golang.org/x/time/rate/rate.go

@@ -0,0 +1,427 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package rate provides a rate limiter.
+package rate
+
+import (
+	"context"
+	"fmt"
+	"math"
+	"sync"
+	"time"
+)
+
+// Limit defines the maximum frequency of some events.
+// Limit is represented as number of events per second.
+// A zero Limit allows no events.
+type Limit float64
+
+// Inf is the infinite rate limit; it allows all events (even if burst is zero).
+const Inf = Limit(math.MaxFloat64)
+
+// Every converts a minimum time interval between events to a Limit.
+func Every(interval time.Duration) Limit {
+	if interval <= 0 {
+		return Inf
+	}
+	return 1 / Limit(interval.Seconds())
+}
+
+// A Limiter controls how frequently events are allowed to happen.
+// It implements a "token bucket" of size b, initially full and refilled
+// at rate r tokens per second.
+// Informally, in any large enough time interval, the Limiter limits the
+// rate to r tokens per second, with a maximum burst size of b events.
+// As a special case, if r == Inf (the infinite rate), b is ignored.
+// See https://en.wikipedia.org/wiki/Token_bucket for more about token buckets.
+//
+// The zero value is a valid Limiter, but it will reject all events.
+// Use NewLimiter to create non-zero Limiters.
+//
+// Limiter has three main methods, Allow, Reserve, and Wait.
+// Most callers should use Wait.
+//
+// Each of the three methods consumes a single token.
+// They differ in their behavior when no token is available.
+// If no token is available, Allow returns false.
+// If no token is available, Reserve returns a reservation for a future token
+// and the amount of time the caller must wait before using it.
+// If no token is available, Wait blocks until one can be obtained
+// or its associated context.Context is canceled.
+//
+// The methods AllowN, ReserveN, and WaitN consume n tokens.
+//
+// Limiter is safe for simultaneous use by multiple goroutines.
+type Limiter struct {
+	mu     sync.Mutex
+	limit  Limit
+	burst  int
+	tokens float64
+	// last is the last time the limiter's tokens field was updated
+	last time.Time
+	// lastEvent is the latest time of a rate-limited event (past or future)
+	lastEvent time.Time
+}
+
+// Limit returns the maximum overall event rate.
+func (lim *Limiter) Limit() Limit {
+	lim.mu.Lock()
+	defer lim.mu.Unlock()
+	return lim.limit
+}
+
+// Burst returns the maximum burst size. Burst is the maximum number of tokens
+// that can be consumed in a single call to Allow, Reserve, or Wait, so higher
+// Burst values allow more events to happen at once.
+// A zero Burst allows no events, unless limit == Inf.
+func (lim *Limiter) Burst() int {
+	lim.mu.Lock()
+	defer lim.mu.Unlock()
+	return lim.burst
+}
+
+// TokensAt returns the number of tokens available at time t.
+func (lim *Limiter) TokensAt(t time.Time) float64 {
+	lim.mu.Lock()
+	tokens := lim.advance(t) // does not mutate lim
+	lim.mu.Unlock()
+	return tokens
+}
+
+// Tokens returns the number of tokens available now.
+func (lim *Limiter) Tokens() float64 {
+	return lim.TokensAt(time.Now())
+}
+
+// NewLimiter returns a new Limiter that allows events up to rate r and permits
+// bursts of at most b tokens.
+func NewLimiter(r Limit, b int) *Limiter {
+	return &Limiter{
+		limit:  r,
+		burst:  b,
+		tokens: float64(b),
+	}
+}
+
+// Allow reports whether an event may happen now.
+func (lim *Limiter) Allow() bool {
+	return lim.AllowN(time.Now(), 1)
+}
+
+// AllowN reports whether n events may happen at time t.
+// Use this method if you intend to drop / skip events that exceed the rate limit.
+// Otherwise use Reserve or Wait.
+func (lim *Limiter) AllowN(t time.Time, n int) bool {
+	return lim.reserveN(t, n, 0).ok
+}
+
+// A Reservation holds information about events that are permitted by a Limiter to happen after a delay.
+// A Reservation may be canceled, which may enable the Limiter to permit additional events.
+type Reservation struct {
+	ok        bool
+	lim       *Limiter
+	tokens    int
+	timeToAct time.Time
+	// This is the Limit at reservation time, it can change later.
+	limit Limit
+}
+
+// OK returns whether the limiter can provide the requested number of tokens
+// within the maximum wait time.  If OK is false, Delay returns InfDuration, and
+// Cancel does nothing.
+func (r *Reservation) OK() bool {
+	return r.ok
+}
+
+// Delay is shorthand for DelayFrom(time.Now()).
+func (r *Reservation) Delay() time.Duration {
+	return r.DelayFrom(time.Now())
+}
+
+// InfDuration is the duration returned by Delay when a Reservation is not OK.
+const InfDuration = time.Duration(math.MaxInt64)
+
+// DelayFrom returns the duration for which the reservation holder must wait
+// before taking the reserved action.  Zero duration means act immediately.
+// InfDuration means the limiter cannot grant the tokens requested in this
+// Reservation within the maximum wait time.
+func (r *Reservation) DelayFrom(t time.Time) time.Duration {
+	if !r.ok {
+		return InfDuration
+	}
+	delay := r.timeToAct.Sub(t)
+	if delay < 0 {
+		return 0
+	}
+	return delay
+}
+
+// Cancel is shorthand for CancelAt(time.Now()).
+func (r *Reservation) Cancel() {
+	r.CancelAt(time.Now())
+}
+
+// CancelAt indicates that the reservation holder will not perform the reserved action
+// and reverses the effects of this Reservation on the rate limit as much as possible,
+// considering that other reservations may have already been made.
+func (r *Reservation) CancelAt(t time.Time) {
+	if !r.ok {
+		return
+	}
+
+	r.lim.mu.Lock()
+	defer r.lim.mu.Unlock()
+
+	if r.lim.limit == Inf || r.tokens == 0 || r.timeToAct.Before(t) {
+		return
+	}
+
+	// calculate tokens to restore
+	// The duration between lim.lastEvent and r.timeToAct tells us how many tokens were reserved
+	// after r was obtained. These tokens should not be restored.
+	restoreTokens := float64(r.tokens) - r.limit.tokensFromDuration(r.lim.lastEvent.Sub(r.timeToAct))
+	if restoreTokens <= 0 {
+		return
+	}
+	// advance time to now
+	tokens := r.lim.advance(t)
+	// calculate new number of tokens
+	tokens += restoreTokens
+	if burst := float64(r.lim.burst); tokens > burst {
+		tokens = burst
+	}
+	// update state
+	r.lim.last = t
+	r.lim.tokens = tokens
+	if r.timeToAct == r.lim.lastEvent {
+		prevEvent := r.timeToAct.Add(r.limit.durationFromTokens(float64(-r.tokens)))
+		if !prevEvent.Before(t) {
+			r.lim.lastEvent = prevEvent
+		}
+	}
+}
+
+// Reserve is shorthand for ReserveN(time.Now(), 1).
+func (lim *Limiter) Reserve() *Reservation {
+	return lim.ReserveN(time.Now(), 1)
+}
+
+// ReserveN returns a Reservation that indicates how long the caller must wait before n events happen.
+// The Limiter takes this Reservation into account when allowing future events.
+// The returned Reservation’s OK() method returns false if n exceeds the Limiter's burst size.
+// Usage example:
+//
+//	r := lim.ReserveN(time.Now(), 1)
+//	if !r.OK() {
+//	  // Not allowed to act! Did you remember to set lim.burst to be > 0 ?
+//	  return
+//	}
+//	time.Sleep(r.Delay())
+//	Act()
+//
+// Use this method if you wish to wait and slow down in accordance with the rate limit without dropping events.
+// If you need to respect a deadline or cancel the delay, use Wait instead.
+// To drop or skip events exceeding rate limit, use Allow instead.
+func (lim *Limiter) ReserveN(t time.Time, n int) *Reservation {
+	r := lim.reserveN(t, n, InfDuration)
+	return &r
+}
+
+// Wait is shorthand for WaitN(ctx, 1).
+func (lim *Limiter) Wait(ctx context.Context) (err error) {
+	return lim.WaitN(ctx, 1)
+}
+
+// WaitN blocks until lim permits n events to happen.
+// It returns an error if n exceeds the Limiter's burst size, the Context is
+// canceled, or the expected wait time exceeds the Context's Deadline.
+// The burst limit is ignored if the rate limit is Inf.
+func (lim *Limiter) WaitN(ctx context.Context, n int) (err error) {
+	// The test code calls lim.wait with a fake timer generator.
+	// This is the real timer generator.
+	newTimer := func(d time.Duration) (<-chan time.Time, func() bool, func()) {
+		timer := time.NewTimer(d)
+		return timer.C, timer.Stop, func() {}
+	}
+
+	return lim.wait(ctx, n, time.Now(), newTimer)
+}
+
+// wait is the internal implementation of WaitN.
+func (lim *Limiter) wait(ctx context.Context, n int, t time.Time, newTimer func(d time.Duration) (<-chan time.Time, func() bool, func())) error {
+	lim.mu.Lock()
+	burst := lim.burst
+	limit := lim.limit
+	lim.mu.Unlock()
+
+	if n > burst && limit != Inf {
+		return fmt.Errorf("rate: Wait(n=%d) exceeds limiter's burst %d", n, burst)
+	}
+	// Check if ctx is already cancelled
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+	// Determine wait limit
+	waitLimit := InfDuration
+	if deadline, ok := ctx.Deadline(); ok {
+		waitLimit = deadline.Sub(t)
+	}
+	// Reserve
+	r := lim.reserveN(t, n, waitLimit)
+	if !r.ok {
+		return fmt.Errorf("rate: Wait(n=%d) would exceed context deadline", n)
+	}
+	// Wait if necessary
+	delay := r.DelayFrom(t)
+	if delay == 0 {
+		return nil
+	}
+	ch, stop, advance := newTimer(delay)
+	defer stop()
+	advance() // only has an effect when testing
+	select {
+	case <-ch:
+		// We can proceed.
+		return nil
+	case <-ctx.Done():
+		// Context was canceled before we could proceed.  Cancel the
+		// reservation, which may permit other events to proceed sooner.
+		r.Cancel()
+		return ctx.Err()
+	}
+}
+
+// SetLimit is shorthand for SetLimitAt(time.Now(), newLimit).
+func (lim *Limiter) SetLimit(newLimit Limit) {
+	lim.SetLimitAt(time.Now(), newLimit)
+}
+
+// SetLimitAt sets a new Limit for the limiter. The new Limit, and Burst, may be violated
+// or underutilized by those which reserved (using Reserve or Wait) but did not yet act
+// before SetLimitAt was called.
+func (lim *Limiter) SetLimitAt(t time.Time, newLimit Limit) {
+	lim.mu.Lock()
+	defer lim.mu.Unlock()
+
+	tokens := lim.advance(t)
+
+	lim.last = t
+	lim.tokens = tokens
+	lim.limit = newLimit
+}
+
+// SetBurst is shorthand for SetBurstAt(time.Now(), newBurst).
+func (lim *Limiter) SetBurst(newBurst int) {
+	lim.SetBurstAt(time.Now(), newBurst)
+}
+
+// SetBurstAt sets a new burst size for the limiter.
+func (lim *Limiter) SetBurstAt(t time.Time, newBurst int) {
+	lim.mu.Lock()
+	defer lim.mu.Unlock()
+
+	tokens := lim.advance(t)
+
+	lim.last = t
+	lim.tokens = tokens
+	lim.burst = newBurst
+}
+
+// reserveN is a helper method for AllowN, ReserveN, and WaitN.
+// maxFutureReserve specifies the maximum reservation wait duration allowed.
+// reserveN returns Reservation, not *Reservation, to avoid allocation in AllowN and WaitN.
+func (lim *Limiter) reserveN(t time.Time, n int, maxFutureReserve time.Duration) Reservation {
+	lim.mu.Lock()
+	defer lim.mu.Unlock()
+
+	if lim.limit == Inf {
+		return Reservation{
+			ok:        true,
+			lim:       lim,
+			tokens:    n,
+			timeToAct: t,
+		}
+	}
+
+	tokens := lim.advance(t)
+
+	// Calculate the remaining number of tokens resulting from the request.
+	tokens -= float64(n)
+
+	// Calculate the wait duration
+	var waitDuration time.Duration
+	if tokens < 0 {
+		waitDuration = lim.limit.durationFromTokens(-tokens)
+	}
+
+	// Decide result
+	ok := n <= lim.burst && waitDuration <= maxFutureReserve
+
+	// Prepare reservation
+	r := Reservation{
+		ok:    ok,
+		lim:   lim,
+		limit: lim.limit,
+	}
+	if ok {
+		r.tokens = n
+		r.timeToAct = t.Add(waitDuration)
+
+		// Update state
+		lim.last = t
+		lim.tokens = tokens
+		lim.lastEvent = r.timeToAct
+	}
+
+	return r
+}
+
+// advance calculates and returns an updated number of tokens for lim
+// resulting from the passage of time.
+// lim is not changed.
+// advance requires that lim.mu is held.
+func (lim *Limiter) advance(t time.Time) (newTokens float64) {
+	last := lim.last
+	if t.Before(last) {
+		last = t
+	}
+
+	// Calculate the new number of tokens, due to time that passed.
+	elapsed := t.Sub(last)
+	delta := lim.limit.tokensFromDuration(elapsed)
+	tokens := lim.tokens + delta
+	if burst := float64(lim.burst); tokens > burst {
+		tokens = burst
+	}
+	return tokens
+}
+
+// durationFromTokens is a unit conversion function from the number of tokens to the duration
+// of time it takes to accumulate them at a rate of limit tokens per second.
+func (limit Limit) durationFromTokens(tokens float64) time.Duration {
+	if limit <= 0 {
+		return InfDuration
+	}
+
+	duration := (tokens / float64(limit)) * float64(time.Second)
+
+	// Cap the duration to the maximum representable int64 value, to avoid overflow.
+	if duration > float64(math.MaxInt64) {
+		return InfDuration
+	}
+
+	return time.Duration(duration)
+}
+
+// tokensFromDuration is a unit conversion function from a time duration to the number of tokens
+// which could be accumulated during that duration at a rate of limit tokens per second.
+func (limit Limit) tokensFromDuration(d time.Duration) float64 {
+	if limit <= 0 {
+		return 0
+	}
+	return d.Seconds() * float64(limit)
+}

vendor/golang.org/x/time/rate/sometimes.go

@@ -0,0 +1,67 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package rate
+
+import (
+	"sync"
+	"time"
+)
+
+// Sometimes will perform an action occasionally.  The First, Every, and
+// Interval fields govern the behavior of Do, which performs the action.
+// A zero Sometimes value will perform an action exactly once.
+//
+// # Example: logging with rate limiting
+//
+//	var sometimes = rate.Sometimes{First: 3, Interval: 10*time.Second}
+//	func Spammy() {
+//	        sometimes.Do(func() { log.Info("here I am!") })
+//	}
+type Sometimes struct {
+	First    int           // if non-zero, the first N calls to Do will run f.
+	Every    int           // if non-zero, every Nth call to Do will run f.
+	Interval time.Duration // if non-zero and Interval has elapsed since f's last run, Do will run f.
+
+	mu    sync.Mutex
+	count int       // number of Do calls
+	last  time.Time // last time f was run
+}
+
+// Do runs the function f as allowed by First, Every, and Interval.
+//
+// The model is a union (not intersection) of filters.  The first call to Do
+// always runs f.  Subsequent calls to Do run f if allowed by First or Every or
+// Interval.
+//
+// A non-zero First:N causes the first N Do(f) calls to run f.
+//
+// A non-zero Every:M causes every Mth Do(f) call, starting with the first, to
+// run f.
+//
+// A non-zero Interval causes Do(f) to run f if Interval has elapsed since
+// Do last ran f.
+//
+// Specifying multiple filters produces the union of these execution streams.
+// For example, specifying both First:N and Every:M causes the first N Do(f)
+// calls and every Mth Do(f) call, starting with the first, to run f.  See
+// Examples for more.
+//
+// If Do is called multiple times simultaneously, the calls will block and run
+// serially.  Therefore, Do is intended for lightweight operations.
+//
+// Because a call to Do may block until f returns, if f causes Do to be called,
+// it will deadlock.
+func (s *Sometimes) Do(f func()) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.count == 0 ||
+		(s.First > 0 && s.count < s.First) ||
+		(s.Every > 0 && s.count%s.Every == 0) ||
+		(s.Interval > 0 && time.Since(s.last) >= s.Interval) {
+		f()
+		s.last = time.Now()
+	}
+	s.count++
+}

vendor/modules.txt

@@ -21,3 +21,6 @@ golang.org/x/sys/windows
 # golang.org/x/term v0.32.0
 ## explicit; go 1.23.0
 golang.org/x/term
+# golang.org/x/time v0.11.0
+## explicit; go 1.23.0
+golang.org/x/time/rate