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SRD-016 — Quiet startup: suppressible banner and configuration dump

Field Value
Status Accepted
Version v.1
Date 2026-06-16
Owner Ruslan Gabitov
Implements ADR-002 v.2 §4.4.1 Extension Architecture

This SRD lands ADR-002 v.2 §4.4.1: two no-argument thresher.New options that each suppress one block of the startup report — WithoutBanner() drops the ASCII wordmark / version / last-commit block, and WithoutStartupConfig() drops the per-extension configuration dump. Both default to on (visible by default — opt-out, never opt-in); the closing separator prints only when a block was emitted, so suppressing both yields a fully silent startup.

1. Background & motivation

1.1 Current state (verified against the code)

  • The startup report is unconditional. Thresher.New calls t.logStartupConfig() after wiring (pkg/thresher/thresher.go:160), with no way to silence it. logStartupConfig (pkg/thresher/thresher.go:168) emits, in order: the banner lines (strings.SplitSeq(banner, "\n")), "GoBPM — BPMN v2 process engine", version:, last commit:, thresher id:, configuration:, one module(...) line per extension, then separator.
  • ADR-002 v.1 forbade an opt-out; v.2 §4.4.1 reverses that, splitting the report into a banner block and a configuration dump, each independently opt-out. This SRD implements that decision.
  • The option machinery already exists. Option = func(*thresherConfig) error (pkg/thresher/options.go:42); New applies each option and wraps the first error (thresher.go:123-131). thresherConfig (options.go:27) holds the nine extensions; defaultConfig() (options.go:201) wires their defaults. The existing WithXxx options are value-setters that reject a nil argument (options.go:45-177).
  • The banner / separator constants live in pkg/thresher/buildinfo.go:13 (banner) and :21 (separator); readBuildInfo() (:36) resolves version + last commit.
  • The current behaviour is covered by TestStartupConfigLog (pkg/thresher/options_test.go:124), which captures records via a capHandler and asserts the human-readable lines are present at INFO.

1.2 Problem

The banner is decorative ASCII printed one INFO record per line — pure noise in a structured log aggregator — and the configuration dump is verbose for embedders that construct many short-lived engines or already capture the wiring elsewhere. The Logger-level lever ADR-002 v.1 pointed at cannot drop this noise without also dropping legitimate application INFO. A per-block opt-out removes the noise precisely while keeping the default loud.

2. Decision

Add two no-argument options to pkg/thresher:

  • WithoutBanner() — suppress the banner block: the ASCII wordmark, the "GoBPM — BPMN v2 process engine" tagline, version:, and last commit:.
  • WithoutStartupConfig() — suppress the configuration block: thresher id:, the configuration: header, and the one-per-extension module(...) lines.

Each option sets an unexported bool on thresherConfig. logStartupConfig consults the two flags and prints each block only when its flag is unset. The separator closes the report iff at least one block printed; with both suppressed, logStartupConfig emits nothing.

The two flags are engine-construction config, not part of renv.EngineRuntime — they are not exposed through the runtime interface and do not touch any executor or waiter.

3. Functional requirements

# Requirement Acceptance
FR-1 WithoutBanner() Option exists; applied, it suppresses the banner block (wordmark, tagline, version:, last commit:). With the option, captured records contain none of those lines; the configuration block and separator are still present.
FR-2 WithoutStartupConfig() Option exists; applied, it suppresses the configuration block (thresher id:, configuration:, per-extension lines). With the option, captured records contain none of those lines; the banner block and separator are still present.
FR-3 The separator prints iff at least one block was emitted. Default → separator present. Both options → zero records emitted (no separator). Either one → separator present.
FR-4 With neither option, startup output is byte-for-byte the pre-change behaviour. TestStartupConfigLog (unchanged assertions) stays green.
FR-5 The options honour the Option contract and compose with the others; order-independent; idempotent. Each returns a non-nil Option; applying twice equals applying once; they do not error (no argument to validate).

4. Non-functional requirements

# Requirement
NFR-1 Visible-by-default preserved: both blocks emit unless explicitly suppressed (opt-out only).
NFR-2 No change to renv.EngineRuntime; the flags are unexported thresherConfig fields. TestConfigSatisfiesEngineRuntime stays green.
NFR-3 Diff-coverage ≥ COVER_MIN (95) on every touched function, aiming 100%.

5. Path analysis (alternatives)

  • (A) Two no-argument options — chosen. WithoutBanner() / WithoutStartupConfig(). Matches the requested granularity (suppress each block independently) and the existing WithXxx family shape. No argument means nothing to validate — the public-API validation rule is satisfied vacuously.
  • (B) One WithQuietStartup() that suppresses everything. Rejected: less granular; cannot drop only the decorative banner while keeping the wiring dump (a common want). The requirement is explicitly two flags.
  • (C) A configurable WithStartupLog(level/mask) enum or variadic. Rejected: over-engineered for two booleans; invents a vocabulary the engine has no other use for.
  • (D) Status quo — silence via the user's Logger level (ADR-002 v.1). Rejected: this was v.1's decision and is the very problem — it cannot separate banner noise from application INFO.

6. API

// WithoutBanner suppresses the startup banner block (the ASCII wordmark, the
// product tagline, the version and the last-commit line). The configuration
// dump still prints unless WithoutStartupConfig is also given.
func WithoutBanner() Option

// WithoutStartupConfig suppresses the startup configuration dump (the thresher
// id, the "configuration:" header and the per-extension lines). The banner
// still prints unless WithoutBanner is also given.
func WithoutStartupConfig() Option

// A fully silent startup:
eng, _ := thresher.New("worker-7",
    thresher.WithoutBanner(),
    thresher.WithoutStartupConfig(),
)

// Keep the build identity, drop the wiring dump:
eng, _ := thresher.New("worker-7", thresher.WithoutStartupConfig())

7. Test plan

Captured via the existing capHandler (options_test.go:113).

# Test Asserts
T-1 TestStartupConfigLog (existing, unchanged) Default: banner + config + separator all present at INFO (FR-4).
T-2 TestWithoutBanner WithoutBanner(): no wordmark/version:/last commit: lines; configuration: + per-extension lines + separator present (FR-1, FR-3).
T-3 TestWithoutStartupConfig WithoutStartupConfig(): no thresher id:/configuration:/per-extension lines; banner + separator present (FR-2, FR-3).
T-4 TestQuietStartup Both options: zero records captured (FR-3).
T-5 TestWithoutBannerIdempotent Applying WithoutBanner() twice == once (FR-5).

8. Cross-document consistency

  • Implements ADR-002 v.2 §4.4.1 (upward reference, version-pinned). No other doc references the startup-report shape.
  • README.md Quick-start area gains a short note on the two options (a reference-doc-style update, landed in this change-set).

9. Definition of Done

  • WithoutBanner() / WithoutStartupConfig() implemented; logStartupConfig branches on the two flags; separator gated on "a block printed".
  • T-1…T-5 green; touched functions at ≥95% diff-coverage (aim 100%).
  • README.md documents the two options.
  • make ci green end to end (tidy → lint → build → race tests → diff-coverage → govulncheck).
  • /check-srd PASS; §10 implementation summary filled; status flipped to Accepted.
  • RU twin added.

10. Implementation summary

Landed on feat/thresher-quiet-startup in four commits; make ci green end to end. /check-srd audit: PASS — FR-1…FR-5 and NFR-1…NFR-3 all wired and tested.

10.1 Commits

Commit Scope
6077ab8 ADR-002 v.2 §4.4.1 — the per-block opt-out decision (EN + RU)
4341778 SRD-016 (this doc) + RU twin
5cea5cb M1 — WithoutBanner() / WithoutStartupConfig() + thresherConfig flags + logStartupConfig two guarded blocks + gated separator + T-2…T-5
74d3ba4 M2 — README "Startup logging" opt-out note

10.2 Key files

  • pkg/thresher/options.go — suppressBanner / suppressStartupConfig fields; WithoutBanner / WithoutStartupConfig options.
  • pkg/thresher/thresher.go — logStartupConfig restructured into a banner block and a config block, readBuildInfo now inside the banner branch, separator gated on printed.
  • pkg/thresher/options_test.go — captureStartup helper + T-2…T-5.
  • README.md — startup-logging opt-out note.

10.3 V-results

  • make ci green (CI_EXIT=0): tidy → lint (0 issues, fieldalignment incl.) → build → race tests (50 pass) → diff-coverage → govulncheck.
  • Touched functions at 100%: logStartupConfig, WithoutBanner, WithoutStartupConfig (≥95 COVER_MIN).
  • examples/basic-process smoke: default startup renders banner + config + separator, process runs, exit 0 (FR-4 — default path unchanged).

Document History

Version Date Author Change
v.1 2026-06-16 Ruslan Gabitov Two no-argument thresher.New options — WithoutBanner() / WithoutStartupConfig() — landing the per-block startup-report opt-out decided in ADR-002 v.2 §4.4.1. Separator gated on "a block printed"; both suppressed ⇒ silent startup. Landed on feat/thresher-quiet-startup (M1 5cea5cb + M2 74d3ba4); /check-srd PASS; status Draft → Accepted.