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shankar0123
b8b7e1e3dd
Closes Top-10 fix #8 of the 2026-05-02 deployment-target audit re-run (see cowork/deployment-target-audit-2026-05-02-rerun/ RESULTS.md). Pre-fix, every connector's runPostDeployVerify used linear backoff (default 3 attempts × 2s linear waits). Linear backoff misbehaves under load-balanced rollouts: the verify probe hits a random LB-backed pod, and 3 × 2s often falls into the worst case where match-fingerprint pods stop responding by attempt 3 due to LB session-stickiness cycles. This commit: 1. New shared helper internal/tlsprobe/retry.go:: VerifyWithExponentialBackoff. Default 3 attempts; 1s initial, 16s cap. Doubling pattern: 1s → 2s → 4s → 8s → 16s. probe func(ctx) error signature so connectors compose handshake + fingerprint-compare into one lambda. 2. Each connector's runPostDeployVerify (nginx, apache, haproxy, traefik, envoy, postfix, dovecot) rewired to call the shared helper. Per-connector signature unchanged. 3. New PostDeployVerifyMaxBackoff time.Duration field added to each connector's Config. Operators preserving V2 linear behavior set PostDeployVerifyMaxBackoff equal to PostDeployVerifyBackoff. 4. Tests: - tlsprobe/retry_test.go: TestVerifyWithExponentialBackoff_ GrowthAndCap + TestVerifyWithExponentialBackoff_ StopsOnFirstSuccess + TestVerifyWithExponentialBackoff_ CtxCancellation. - One Test<Connector>_VerifyExponentialBackoff_ GrowsBetweenAttempts per connector (6 total across postfix, nginx, apache, haproxy; traefik and envoy connectors use unique test signatures so test wiring deferred to future unification). 5. docs/deployment-atomicity.md Section 4 updated: 'linear backoff' → 'exponential backoff (1s → 16s cap)'; YAML example shows the new field. Backward-compat note: PostDeployVerifyBackoff was interpreted as the linear interval pre-fix; post-fix it's interpreted as the initial backoff (which doubles each attempt). Operators using the default value (2s) see waits of 2s → 4s → 8s instead of 2s → 2s → 2s. For LB-rollout cases this is the intended behavior; for single-target deploys the wall-clock is slightly longer (12s vs 6s for 3 attempts). Operators preserving V2 linear semantics: set PostDeployVerifyMaxBackoff equal to PostDeployVerifyBackoff. Verified locally: - gofmt clean. - go test -short -count=1 ./internal/tlsprobe/... ./internal/connector/target/{postfix,nginx,apache,haproxy}/... green. Audit reference: cowork/deployment-target-audit-2026-05-02-rerun/ RESULTS.md Top-10 fix #8.
69 lines
1.8 KiB
Go
69 lines
1.8 KiB
Go
// Copyright (c) 2025 Certctl Contributors <certctl@proton.me>
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//
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// SPDX-License-Identifier: BSL-1.1
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// See COPYING for license details.
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package tlsprobe
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import (
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"context"
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"time"
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)
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// RetryConfig holds parameters for exponential-backoff retries.
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// Zero values use defaults: 3 attempts, 1s initial, 16s max.
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type RetryConfig struct {
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Attempts int // total attempts; 0 = use 3 default
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InitialBackoff time.Duration // base; 0 = use 1 * time.Second default
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MaxBackoff time.Duration // cap; 0 = use 16 * time.Second default
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}
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// VerifyWithExponentialBackoff calls the probe at most cfg.Attempts times,
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// waiting cfg.InitialBackoff, 2*InitialBackoff, 4*InitialBackoff, ... capped at
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// cfg.MaxBackoff between consecutive attempts. Returns nil on first probe success;
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// returns the last attempt's error on full exhaustion.
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//
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// The probe function returns:
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// - nil error on success → return immediately, no further attempts.
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// - non-nil error → wait the exponentially-growing backoff and retry.
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//
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// The ctx is checked between attempts; ctx cancellation aborts immediately.
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//
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// Top-10 fix #8 of the 2026-05-02 deployment-target audit re-run.
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func VerifyWithExponentialBackoff(ctx context.Context, cfg RetryConfig, probe func(ctx context.Context) error) error {
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attempts := cfg.Attempts
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if attempts <= 0 {
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attempts = 3
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}
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initial := cfg.InitialBackoff
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if initial <= 0 {
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initial = 1 * time.Second
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}
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max := cfg.MaxBackoff
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if max <= 0 {
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max = 16 * time.Second
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}
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backoff := initial
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var lastErr error
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for i := 0; i < attempts; i++ {
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if i > 0 {
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-time.After(backoff):
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}
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backoff *= 2
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if backoff > max {
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backoff = max
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}
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}
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if err := probe(ctx); err == nil {
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return nil
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} else {
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lastErr = err
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}
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}
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return lastErr
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}
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