mirror of
https://github.com/imjasonh/esp32
synced 2026-07-06 23:52:24 +00:00
Jason Hall
f0c23bbe1b
The metrics work in PR #10 added a third concurrent TLS client (metrics → monitoring.googleapis.com) on top of cloud_log → logging and OTA → ghcr. Three concurrent handshakes pinned ~90 KB of mbedtls context and pushed `min_free_heap` into the single-digit-KB range, producing intermittent ESP_ERR_HTTP_CONNECT failures (mbedtls ALLOC_FAILED at -0x7F00). Serialize via a shared `Arc<Mutex<()>>` constructed in main and held **at the call sites** in each sender — std `Mutex` isn't reentrant and `auth.get_or_refresh()` mints a token (an HTTPS POST to oauth2) that must run inside the same critical section. Lock granularity: - cloud_log: token-refresh + entries:write under one lock window. - metrics: token-refresh + timeSeries.create under one lock window. - ota::poll_once: token + manifest under lock; release for the signature bundle fetch's lock; release; verify (CPU, no TLS); download_and_apply UNLOCKED. Releasing between phases avoids blocking cloud_log/metrics behind ~2s of pure-Rust X.509/ECDSA work. - ota::download_and_apply: deliberately not in the lock — multi-second blob downloads must not block per-5-s log flushes or per-30-s metrics POSTs. Plus mbedtls heap knobs that compose with the dynamic-buffer config already in sdkconfig: - CONFIG_MBEDTLS_SSL_KEEP_PEER_CERTIFICATE=n: drop the parsed peer cert chain after handshake. We don't reuse sessions or do mutual TLS, so we never need it post-handshake. Saves ~3-5 KB per active session. Known limitation, deferred to a follow-up: cloud_log/metrics handshakes can still collide with the held-open OTA download session and OOM the download mid-stream. The plan there is an `OTA_DOWNLOAD_IN_PROGRESS` atomic that cloud_log + metrics check before locking — they skip the POST and let the queue accumulate until the download finishes. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
48 lines
2.4 KiB
Text
48 lines
2.4 KiB
Text
CONFIG_ESP_MAIN_TASK_STACK_SIZE=7000
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# Default for std::thread::spawn() without explicit stack_size. Bumped from
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# 8192 because anything that does HTTPS + JSON + SHA blows past 8 KB.
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CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT=16384
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# HTTPS via ESP-IDF's bundled root CA store (esp_crt_bundle_attach in main.rs)
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CONFIG_MBEDTLS_CERTIFICATE_BUNDLE=y
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CONFIG_MBEDTLS_CERTIFICATE_BUNDLE_DEFAULT_FULL=y
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# mbedtls heap budgeting. We routinely have 2-3 concurrent TLS sessions
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# (cloud_log → logging.googleapis.com, metrics → monitoring.googleapis.com,
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# OTA → ghcr.io / pkg-containers); without these knobs the per-session
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# heap pinned for I/O buffers + cert chain blows our budget and the
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# next handshake fails with MBEDTLS_ERR_SSL_ALLOC_FAILED (-0x7F00).
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#
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# Even with serialization (cloud_log + metrics + OTA short fetches share
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# a Mutex; OTA blob download deliberately doesn't), the OTA download
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# holds its session open for tens of seconds while metrics/cloud_log
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# handshakes need to fit alongside it.
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#
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# - DYNAMIC_BUFFER: I/O buffers grow per-session up to the configured
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# max instead of being pinned at 16+16 KB.
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# - DYNAMIC_FREE_CONFIG_DATA: free the mbedtls_ssl_config struct after
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# handshake.
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# - DYNAMIC_FREE_CA_CERT: drop the CA bundle data after handshake (we
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# re-attach it from esp_crt_bundle on the next handshake).
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# - SSL_KEEP_PEER_CERTIFICATE=n: drop the parsed peer cert chain after
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# handshake. We don't reuse sessions or do mutual TLS, so we never
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# need it post-handshake. Saves ~3-5 KB per active session.
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CONFIG_MBEDTLS_DYNAMIC_BUFFER=y
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CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA=y
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CONFIG_MBEDTLS_DYNAMIC_FREE_CA_CERT=y
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CONFIG_MBEDTLS_SSL_KEEP_PEER_CERTIFICATE=n
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# OTA: custom partition table with two app slots, plus app-rollback support
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# so a bad OTA can be reverted by the bootloader on next boot.
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CONFIG_PARTITION_TABLE_CUSTOM=y
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# Absolute path because IDF resolves this relative to its CMake project,
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# which for embuild is the synthetic project under target/, not our repo
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# root. The Makefile generates sdkconfig.defaults from this template
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# (sdkconfig.defaults.in), substituting @PROJECT_DIR@ at build time.
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CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="@PROJECT_DIR@/partitions.csv"
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CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y
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# Inland board has 4MB flash; default IDF assumes 2MB which is too small
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# for our 1.5MB-each OTA partition layout.
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CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
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CONFIG_ESPTOOLPY_FLASHSIZE="4MB"
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