fix: reduce Docker layers, add auto CI trigger, fix fake ops import by JacoCheung · Pull Request #363 · NVIDIA/recsys-examples

JacoCheung · 2026-04-14T14:11:22Z

Summary

Merge RUN instructions in docker/Dockerfile to reduce total layer count, fixing the overlay2 128-layer limit (max depth exceeded) on CI nodes. Saves 12 layers (~119 total).
Add pull_request_target trigger to blossom-ci.yml so CI runs automatically on PR open/update (no need to manually comment /build)
Cherry-pick fix for fake ops wrapper import used in torch export (from @geoffreyQiu)
Enhance /build command: support /build devel and /build nightly flags to pass BUILD_DEVEL=1 / NIGHTLY_TEST=1 to GitLab pipeline (companion change in GitLab MR !125)

Dockerfile Changes

Stage	Before	After	Saved
devel stage RUN	8	4	-4
build stage RUN	4	1	-3
Total new layers	21	9	-12

blossom-ci.yml Changes

Added pull_request_target: [opened, synchronize] trigger
Updated if condition: startsWith(comment.body, '/build') to support /build devel, /build nightly, /build devel nightly

`/build` Flag Support

Command	Effect
`/build`	Normal CI (unchanged)
`/build devel`	Rebuild base Docker images (`BUILD_DEVEL=1`)
`/build nightly`	Run 8-GPU nightly tests (`NIGHTLY_TEST=1`)
`/build devel nightly`	Both

CI

Test plan

CI inference_build + inference_test_1gpu pass (no more max depth exceeded)
train_build + unit tests unaffected
Auto CI trigger works on PR open/sync after merge to main
/build devel triggers pipeline with BUILD_DEVEL=1 (requires GitLab MR !125 merged first)

🤖 Generated with Claude Code

greptile-apps · 2026-04-14T14:12:55Z

Greptile Summary

This PR consolidates Dockerfile RUN instructions from ~21 to ~9 layers (saving 12 layers) to fix the overlay2 max depth exceeded error on CI nodes, extends the /build comment trigger to support startsWith matching for /build devel and /build nightly flags, and cherry-picks the correct fake-ops import ordering needed for torch.export.

The PR description states that a pull_request_target: [opened, synchronize] trigger was added to blossom-ci.yml, but it is absent from the actual diff and the current file — the workflow still only fires on issue_comment and workflow_dispatch. The test plan item "Auto CI trigger works on PR open/sync after merge to main" remains unchecked, suggesting this feature was not implemented in this PR.

Confidence Score: 5/5

Safe to merge — all functional changes are correct; the only finding is a P2 description/code mismatch.

No P0 or P1 findings. The Dockerfile layer consolidation is functionally equivalent to the original. The Python fake-ops import ordering is correct and uses the established isort: off/on pattern. The startsWith change in blossom-ci.yml is a clean and safe extension of the existing trigger. The single P2 comment is about the PR description claiming a feature (pull_request_target trigger) that is not actually present in the code — this does not affect runtime behavior.

.github/workflows/blossom-ci.yml — verify whether the pull_request_target trigger was intentionally omitted or is a missing implementation.

Important Files Changed

Filename	Overview
.github/workflows/blossom-ci.yml	Updated `if` condition from exact `/build` match to `startsWith` to support `/build devel` and `/build nightly` flags; PR description claims `pull_request_target` trigger was added but it is absent from the actual file.
docker/Dockerfile	Merged 8 devel-stage RUN instructions into 4 and 4 build-stage RUN instructions into 1, reducing total Docker layers by 12 to resolve the overlay2 128-layer limit; changes are functionally equivalent to the original.
examples/hstu/modules/exportable_embedding.py	Added ordered fake-ops imports (dynamicemb meta, hstu_cuda_ops, fake_hstu_cuda_ops) under `isort: off/on` guard to ensure correct op registration sequence before torch.export.
examples/hstu/ops/fused_hstu_op.py	Added `import hstu.hstu_ops_gpu` to register fake implementations needed for torch.export; minimal and correct change.

Sequence Diagram

sequenceDiagram
    participant Dev as Developer
    participant GH as GitHub PR
    participant BCI as Blossom CI (GH Action)
    participant GL as GitLab Pipeline

    Dev->>GH: Comment /build [devel|nightly]
    GH->>BCI: issue_comment event (created)
    BCI->>BCI: Authorization: actor in allowlist?
    BCI->>BCI: Authorization: startsWith(body, '/build')?
    BCI->>BCI: Vulnerability scan (checkout + blossom-action)
    BCI->>GL: START-CI-JOB (blossom-ci, passes flags)
    GL-->>GH: Pipeline status reported back

_{Reviews (13): Last reviewed commit: "ci: remove pull_request_target trigger, ..." | Re-trigger Greptile}

Aggressively merge RUN instructions in the Dockerfile to reduce total layer count from ~126 to ~119. The inference image was hitting the overlay2 128-layer limit ("failed to register layer: max depth exceeded") on CI nodes. devel stage: 8 RUN + 1 COPY -> 4 RUN + 1 COPY (-4 layers) build stage: 4 RUN + 1 COPY -> 1 RUN + 1 COPY (-3 layers) FBGEMM and TorchRec kept as separate layers for build cache efficiency. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-15T05:26:10Z

/build

EmmaQiaoCh · 2026-04-15T05:58:43Z

/build

JacoCheung · 2026-04-15T06:42:37Z

/build

shijieliu · 2026-04-15T07:05:38Z

/build

shijieliu · 2026-04-15T07:07:19Z

/ci

JacoCheung · 2026-04-15T07:09:48Z

/ci

JacoCheung · 2026-04-15T07:16:40Z

/build

JacoCheung · 2026-04-15T07:19:47Z

/ci

shijieliu · 2026-04-15T09:58:00Z

/build

EmmaQiaoCh · 2026-04-15T09:58:49Z

/build

JacoCheung · 2026-04-15T09:58:55Z

/build

JacoCheung · 2026-04-15T10:08:13Z

/build

JacoCheung · 2026-04-15T10:13:28Z

/build

JacoCheung · 2026-04-15T10:42:38Z

/build

JacoCheung · 2026-04-15T10:51:31Z

/build

JacoCheung · 2026-04-15T11:00:03Z

/build

JacoCheung · 2026-04-15T11:07:41Z

/build

JacoCheung · 2026-04-15T11:13:45Z

/build

JacoCheung · 2026-04-15T11:16:16Z

/build

JacoCheung · 2026-04-15T11:22:23Z

/build

JacoCheung · 2026-04-15T11:28:44Z

/build

JacoCheung · 2026-04-15T11:34:36Z

/build

JacoCheung · 2026-04-15T12:15:58Z

/build

JacoCheung · 2026-04-15T12:22:08Z

/build

JacoCheung · 2026-04-15T13:42:47Z

/build

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-16T01:22:28Z

/build

JacoCheung · 2026-04-16T01:32:53Z

/build

JacoCheung · 2026-04-16T01:45:48Z

/build

JacoCheung · 2026-04-16T01:50:05Z

❔ Pipeline #48650175 -- canceling

Job	Status	Log
pre_check	✅ success	view
train_build	✅ success	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	❌ failed	view
dynamicemb_test_fwd_bwd_8gpus	✅ success	view
dynamicemb_test_load_dump_8gpus	❔ canceling	view
unit_test_1gpu_a100	❌ failed	view
unit_test_1gpu_h100	❌ failed	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	❌ failed	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	❌ failed	view

View full pipeline

The module hstu.hstu_ops_gpu does not exist as a Python module. The C++ source hstu_ops_gpu.cpp compiles into hstu/fbgemm_gpu_experimental_hstu.so, not a separate hstu_ops_gpu submodule. This import was incorrectly added in PR NVIDIA#327 and causes ModuleNotFoundError in CI. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-16T03:29:18Z

/build

JacoCheung · 2026-04-16T03:46:03Z

/build

JacoCheung · 2026-04-16T03:50:16Z

❌ Pipeline #48656842 -- failed

Job	Status	Log
pre_check	✅ success	view
train_build	✅ success	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	✅ success	view
dynamicemb_test_fwd_bwd_8gpus	❌ failed	view
dynamicemb_test_load_dump_8gpus	✅ success	view
unit_test_1gpu_a100	✅ success	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	✅ success	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	❌ failed	view
unit_test_1gpu_h100	✅ success	view

Result: 10/14 jobs passed

View full pipeline

Update from 04df536 to 65bad42 which adds fake tensor implementations for torch.export (hstu_ops_gpu.py). This was missing since PR NVIDIA#340 accidentally reverted the submodule pointer. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-16T07:01:50Z

/build

JacoCheung · 2026-04-16T07:06:21Z

❌ Pipeline #48669643 -- failed

Job	Status	Log
pre_check	✅ success	view
train_build	✅ success	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	❌ failed	view
dynamicemb_test_fwd_bwd_8gpus	❌ failed	view
dynamicemb_test_load_dump_8gpus	✅ success	view
unit_test_1gpu_a100	❌ failed	view
unit_test_1gpu_h100	❌ failed	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	✅ success	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	✅ success	view

Result: 8/14 jobs passed

View full pipeline

JacoCheung · 2026-04-16T09:25:44Z

/build

JacoCheung · 2026-04-16T09:30:05Z

❌ Pipeline #48680124 -- failed

Job	Status	Log
pre_check	✅ success	view
train_build	✅ success	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	✅ success	view
dynamicemb_test_fwd_bwd_8gpus	✅ success	view
dynamicemb_test_load_dump_8gpus	✅ success	view
unit_test_1gpu_a100	❌ failed	view
unit_test_1gpu_h100	❌ failed	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	✅ success	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	✅ success	view

Result: 10/14 jobs passed

View full pipeline

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-16T14:33:44Z

/build

JacoCheung · 2026-04-16T14:38:20Z

❌ Pipeline #48697202 -- failed

Job	Status	Log
pre_check	✅ success	view
train_build	❌ failed	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	❌ failed	view
dynamicemb_test_fwd_bwd_8gpus	❌ failed	view
dynamicemb_test_load_dump_8gpus	❌ failed	view
unit_test_1gpu_a100	❌ failed	view
unit_test_1gpu_h100	❌ failed	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	❌ failed	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	✅ success	view

Result: 5/14 jobs passed

View full pipeline

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung · 2026-04-16T15:32:12Z

/build

JacoCheung · 2026-04-16T15:37:37Z

❌ Pipeline #48700740 -- failed

Job	Status	Log
pre_check	✅ success	view
train_build	✅ success	view
inference_build	✅ success	view
tritonserver_build	✅ success	view
build_whl	✅ success	view
dynamicemb_test_fwd_bwd_8gpus	✅ success	view
dynamicemb_test_load_dump_8gpus	✅ success	view
unit_test_1gpu_a100	✅ success	view
unit_test_1gpu_h100	❌ failed	view
unit_test_4gpu	❌ failed	view
unit_test_tp_4gpu	❌ failed	view
L20_unit_test_1gpu	✅ success	view
inference_unit_test_1gpu	✅ success	view
inference_test_1gpu	✅ success	view

Result: 11/14 jobs passed

View full pipeline

greptile-apps bot reviewed Apr 14, 2026

View reviewed changes

Comment thread docker/Dockerfile Outdated

JacoCheung force-pushed the fix/reduce-docker-layers branch from b816ab3 to df8ec8a Compare April 14, 2026 14:13

greptile-apps bot reviewed Apr 14, 2026

View reviewed changes

Comment thread docker/Dockerfile Outdated

JacoCheung force-pushed the fix/reduce-docker-layers branch from df8ec8a to a105838 Compare April 14, 2026 14:37

greptile-apps bot reviewed Apr 15, 2026

View reviewed changes

Comment thread .github/workflows/gitlab-ci-bridge.yml Outdated

JacoCheung force-pushed the fix/reduce-docker-layers branch from 0279dc3 to a105838 Compare April 15, 2026 08:57

ci: add pull_request_target trigger for auto CI on PR open/sync

2add288

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

JacoCheung requested a review from shijieliu April 15, 2026 15:51

Fix imports for fake ops wrapper used in expor

b0747ae

JacoCheung mentioned this pull request Apr 16, 2026

Fix imports for fake op wrappers used in export #366

Closed

JacoCheung changed the title ~~fix: reduce Docker image layers to avoid overlay2 max depth~~ fix: reduce Docker layers, add auto CI trigger, fix fake ops import Apr 16, 2026

greptile-apps bot reviewed Apr 16, 2026

View reviewed changes

Comment thread .github/workflows/blossom-ci.yml Outdated

ci: allow /build with flags by matching prefix instead of exact string

a9b3023

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ci: remove pull_request_target trigger, keep only /build comment

6010291

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shijieliu approved these changes Apr 17, 2026

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shijieliu merged commit bb398ee into NVIDIA:main Apr 17, 2026
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JacoCheung commented Apr 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Dockerfile Changes

blossom-ci.yml Changes

/build Flag Support

CI

Test plan

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Greptile Summary

Confidence Score: 5/5

Important Files Changed

Sequence Diagram

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`/build` Flag Support

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