Resolves#14. ApplyTierConfig now reads TIER{2,3,4}_MEMORY_MB and
TIER{2,3,4}_CPU_SHARES env vars, falling back to the compiled defaults
agreed in the issue:
- T2: 512 MiB / 1024 shares (1 CPU) — unchanged baseline
- T3: 2048 MiB / 2048 shares (2 CPU) — new cap (previously uncapped)
- T4: 4096 MiB / 4096 shares (4 CPU) — new cap (previously uncapped)
CPU_SHARES follows Docker's 1024 = 1 CPU convention; internally the
value is translated to NanoCPUs for a hard allocation so behaviour
remains deterministic across hosts. Malformed or non-positive env
values silently fall back to the default.
Behaviour change note: T3 and T4 previously had no explicit cap.
Operators who relied on unlimited can set very large TIERn_MEMORY_MB /
TIERn_CPU_SHARES values; a follow-up can add unset-means-unlimited
semantics if required.
Tests:
- TestGetTierMemoryMB_DefaultsMatchLegacy
- TestGetTierMemoryMB_EnvOverride (covers malformed + zero fallback)
- TestGetTierCPUShares_EnvOverride
- TestApplyTierConfig_T3_UsesEnvOverride (wiring)
- TestApplyTierConfig_T3_DefaultCap (documents the new cap)
Docs: .env.example section + CLAUDE.md platform env-vars list updated.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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