fix: increase max rate limit usage

Signed-off-by: Carlos Alexandro Becker <[email protected]>

config/config.go

@@ -7,10 +7,11 @@ import (
 
 // Config configuration.
 type Config struct {
-	RedisURL       string   `env:"REDIS_URL" envDefault:"redis://localhost:6379"`
-	GitHubTokens   []string `env:"GITHUB_TOKENS"`
-	GitHubPageSize int      `env:"GITHUB_PAGE_SIZE" envDefault:"100"`
-	Port           string   `env:"PORT" envDefault:"3000"`
+	RedisURL              string   `env:"REDIS_URL" envDefault:"redis://localhost:6379"`
+	GitHubTokens          []string `env:"GITHUB_TOKENS"`
+	GitHubPageSize        int      `env:"GITHUB_PAGE_SIZE" envDefault:"100"`
+	GitHubMaxRateUsagePct int      `env:"GITHUB_MAX_RATE_LIMIT_USAGE" envDefault:"80"`
+	Port                  string   `env:"PORT" envDefault:"3000"`
 }
 
 // Get the current Config.

internal/github/github.go

@@ -25,6 +25,7 @@ type GitHub struct {
 	tokens   roundrobin.RoundRobiner
 	pageSize int
 	cache    *cache.Redis
+	maxRateUsagePct int
 }
 
 var rateLimits = prometheus.NewCounter(prometheus.CounterOpts{
@@ -131,10 +132,14 @@ func (gh *GitHub) checkToken(token *roundrobin.Token) error {
 	rate := limit.Rate
 	log.Debugf("%s rate %d/%d", token, rate.Remaining, rate.Limit)
 	rateLimiters.WithLabelValues(token.String()).Set(float64(rate.Remaining))
-	if rate.Remaining > rate.Limit/2 {
-		return nil // allow at most 50% rate limit usage
+	if isAboveTargetUsage(rate, gh.maxRateUsagePct) {
+		return fmt.Errorf("token usage is too high: %d/%d", rate.Remaining, rate.Limit)
 	}
-	return fmt.Errorf("token usage is too high: %d/%d", rate.Remaining, rate.Limit)
+	return nil // allow at most x% rate limit usage
+}
+
+func isAboveTargetUsage(rate rate, target int) bool {
+	return rate.Remaining*100 / rate.Limit < target
 }
 
 type rateLimit struct {

internal/github/github_test.go

@@ -0,0 +1,31 @@
+package github
+
+import (
+	"testing"
+
+	"github.com/matryer/is"
+)
+
+func TestIsRateAboveLimit(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(false, isAboveTargetUsage(rate{
+		Remaining: 4000,
+		Limit:     5000,
+	}, 50))
+
+	is.Equal(false, isAboveTargetUsage(rate{
+		Remaining: 2500,
+		Limit:     5000,
+	}, 50))
+
+	is.Equal(true, isAboveTargetUsage(rate{
+		Remaining: 2499,
+		Limit:     5000,
+	}, 50))
+
+	is.Equal(true, isAboveTargetUsage(rate{
+		Remaining: 500,
+		Limit:     5000,
+	}, 80))
+}