/tags/go/Recent content in Go on Momo Engineering Journal/images/og-image.png/images/og-image.pngHugoen-usTue, 20 Oct 2026 21:38:57 -0600/posts/049-eliminate-redundant-time-format-allocations/Sat, 12 Sep 2026 00:00:00 +0000/posts/049-eliminate-redundant-time-format-allocations/By replacing a second <code>time.Format</code> call with a simple string slice (<code>amzDate[:8]</code>), we eliminated redundant heap allocations and CPU overhead when generating timestamps for AWS SigV4 requests./posts/029-fuse-go-fuse-v2-migration/Tue, 01 Sep 2026 18:40:07 +0000/posts/029-fuse-go-fuse-v2-migration/The momofs FUSE mount traded its hand-rolled bazil.org/fuse adapter for the go-fuse/v2 high-level fs API, mapped all 22 node callbacks to go-fuse interfaces, and deprecated consistency=cached./posts/045-bolt-lastmodified-header/Tue, 01 Sep 2026 11:19:08 +0000/posts/045-bolt-lastmodified-header/time.Format allocates a fresh string on every S3 GET/HEAD response. Swapping to time.AppendFormat drops that heap escape to zero — measured 32 B/op saved per request on the hottest read path./posts/023-momofs-fuse-transport/Fri, 28 Aug 2026 15:57:34 +0000/posts/023-momofs-fuse-transport/The FUSE transport (<code>momo -imp fs</code>): bazil.org/fuse binding, per-handle buffered writes, /dev/fuse-gated e2e, and a clean unmount lifecycle./posts/025-benchmark-benchstat-gate/Fri, 28 Aug 2026 00:32:50 +0000/posts/025-benchmark-benchstat-gate/Base-vs-branch benchmark comparison gates every PR — plus the runner-noise saga (S3PutSpool, LocalWrite, allowlist, apostrophe) that made it honest./posts/022-momofs-posix-core/Thu, 27 Aug 2026 22:40:31 +0000/posts/022-momofs-posix-core/The R4 POSIX core: inodes as content-addressed manifests, files as blobs, atomic rename, hardlinks, permission enforcement — a filesystem on momo./posts/021-r3-write-durability-quorum/Thu, 27 Aug 2026 19:24:05 +0000/posts/021-r3-write-durability-quorum/Ack only what survived: fsync/group-commit durability barrier, survivor quorum, and read-your-writes — the write-side of the P0 stack./posts/020-r2-degraded-read-self-heal/Thu, 27 Aug 2026 10:14:18 +0000/posts/020-r2-degraded-read-self-heal/When a local replica is corrupted or missing, degraded read fetches from healthy survivors transparently, while a background rebuild loop restores cluster redundancy./posts/019-r1-failure-domain-placement/Wed, 26 Aug 2026 23:52:57 +0000/posts/019-r1-failure-domain-placement/Replicas must not ride in the same rack: CRUSH weights become rack/zone/DC-aware so a single domain failure can&rsquo;t lose the data./posts/026-metrics-observability/Tue, 25 Aug 2026 06:12:59 +0000/posts/026-metrics-observability/Prometheus metrics export with a per-node metrics_host/metrics_port bind — observability that scales past the &lsquo;just scrape node 0&rsquo; era./posts/028-roadmap-and-research/Tue, 25 Aug 2026 03:24:12 +0000/posts/028-roadmap-and-research/After R1–R4: the P0 hardening done, the P1/P2 tracks (metrics, HA metadata, auth, secrets, S3 breadth) and the research reading guide that seeded it all./posts/007-at-rest-integrity-and-gc/Mon, 24 Aug 2026 19:36:43 +0000/posts/007-at-rest-integrity-and-gc/CAS keys make verify-on-read free: central verification, x-amz-checksum echo, tombstone GC, and corruption surfacing./posts/012-s3-integrity-checksums/Mon, 24 Aug 2026 16:36:34 +0000/posts/012-s3-integrity-checksums/x-amz-checksum-CRC32/SHA256 echo on PUT; integrity surfaced to clients so dirty bytes never masquerade as clean. Teaches: client-verifiable integrity, Bolt zero-allocation on read path, Sentinel honesty guarantee./posts/018-adaptive-scaling-peer-quality/Fri, 14 Aug 2026 19:43:24 +0000/posts/018-adaptive-scaling-peer-quality/Three adaptive feedback loops: gossip fanout scales with cluster size, streaming chunk size adapts to cipher/memory, peer quality feeds quorum decisions./posts/014-confidential-dedup-oprf/Fri, 14 Aug 2026 00:26:56 +0000/posts/014-confidential-dedup-oprf/Threshold-OPRF lets E2EE cas blobs dedup without revealing content hashes — plus adaptive failed-auth backoff and lockout./posts/017-scatter-gather-lease-quorum/Thu, 13 Aug 2026 07:58:21 +0000/posts/017-scatter-gather-lease-quorum/Scatter-gather lists across shard owners; leases with correct majority quorum — and the two nasty off-by-one/partition bugs found by audit./posts/009-s3-multipart-and-breadth/Thu, 13 Aug 2026 06:02:26 +0000/posts/009-s3-multipart-and-breadth/Multipart upload support plus a rigorous 501 strategy for unsupported S3 subresources — honest breadths over silent misbehavior./posts/024-bolt-performance-engineering/Wed, 12 Aug 2026 11:40:41 +0000/posts/024-bolt-performance-engineering/The Bolt mindset codified: no heap escapes in hashing/encoding, deadline amortization cuts SetDeadline ~98%, allocation hotspots hunted by profile. Teaches: zero-escape patterns, measurement contracts, trade-off posture./posts/011-s3-https-tls-enforcement/Wed, 12 Aug 2026 07:23:29 +0000/posts/011-s3-https-tls-enforcement/The S3 gateway turned HTTPS-or-explicit-insecure into the default: no silent plaintext for the gateway or inbound tcp/quic./posts/010-s3-auth-presigned-sigv4/Tue, 11 Aug 2026 23:11:16 +0000/posts/010-s3-auth-presigned-sigv4/Query-string SigV4 for presigned URLs, mandatory X-Amz-Date freshness, and decoupling gateway access/secret keys from the native auth token./posts/008-s3-gateway-core/Tue, 11 Aug 2026 18:25:16 +0000/posts/008-s3-gateway-core/The S3 gateway: SigV4, S3-compliant XML errors, Head/List/Copy, pagination, ranges, and metadata — a compatible API surface for real clients./posts/013-e2ee-envelope-encryption/Tue, 11 Aug 2026 16:36:53 +0000/posts/013-e2ee-envelope-encryption/Envelope encryption with a client-held key: the server stores ciphertext and can&rsquo;t read it — across S3 and native transports./posts/003-transport-tcp-to-quic/Tue, 11 Aug 2026 04:02:50 +0000/posts/003-transport-tcp-to-quic/Momo&rsquo;s transport layer grew from TCP to a QUIC/TLS 1.3 fan-out — fixing handshake, ACK framing, deadlines, and TLS identity along the way./posts/015-sentinel-security-audit/Tue, 04 Aug 2026 00:47:24 +0000/posts/015-sentinel-security-audit/A 76-deep audit (authed via Sentinel) surfaced CRLF injection, smuggling, traversal and path leaks — the pattern that forged momo&rsquo;s security mindset./posts/006-pluggable-storage-backends/Sun, 26 Jul 2026 14:33:59 +0000/posts/006-pluggable-storage-backends/The <code>[storage] backend</code> seam swaps blob storage (local, nfs, s3, raw) behind one Store interface, keeping CAS metadata local./posts/005-crush-placement/Tue, 30 Jun 2026 13:09:01 +0000/posts/005-crush-placement/Weighted rendezvous hashing picks replicas deterministically and peer-equally without a central allocator — later hardened for failure domains. Teaches: content-hash-based placement, weighted rendezvous hashing, deterministic stable sort, failure domain filtering./posts/002-replication-strategies-polymorphic/Mon, 04 May 2026 18:54:37 +0000/posts/002-replication-strategies-polymorphic/Chain, Splay, and Primary-Splay replication — and the metrics-driven controller that switches between them at runtime./posts/004-cas-content-addressable-store/Wed, 11 Mar 2026 14:34:18 +0000/posts/004-cas-content-addressable-store/Identify every object by its SHA-256 content hash — server-side dedup, verify-on-read, and a path that later mounted a filesystem. Teaches: content addressing principles, single write chokepoint, Bolt/Sentinel patterns./posts/016-p2p-gossip-swim/Wed, 11 Mar 2026 14:34:18 +0000/posts/016-p2p-gossip-swim/A scaleless-gossip ring: SWIM-style failure detection, discovered-peer dialing, and ALIVE/OFFLINE restoration — momo&rsquo;s nervous system./posts/001-origin-and-genesis/Tue, 09 Sep 2025 20:10:05 +0000/posts/001-origin-and-genesis/How momo started as a file-replication playground in Go and grew into a distributed content-addressed object store.