Skip to content

Reduce downstream plugin needs through YAML-driven configuration enhancements #928

Open
Feature
Open
Reduce downstream plugin needs through YAML-driven configuration enhancements#928
Feature

Description

@EmilienM
EmilienM
opened on Feb 25, 2026

Plugin Reduction Analysis: Moving Intelligence from Builder to Fromager

Executive Summary

Analysis of 62 package plugins and 171 YAML settings files in the AIPCC wheels builder reveals that ~30 plugins (48%) could be fully eliminated and ~12 more (19%) significantly simplified by adding targeted features to Fromager. The remaining ~20 plugins (32%) contain genuinely complex, package-specific logic that must remain as plugins.

The highest-impact Fromager enhancements, ranked by plugin elimination potential:

Proposed Fromager Feature Plugins Eliminated Plugins Simplified
YAML-driven resolver configuration (GitLab/GitHub tag provider) 11 fully 16 partially
Auto-detect ensure_pkg_info need 3 fully 13 partially
YAML-driven dependency patching (remove_install_requires) 3 fully 4 partially
YAML-driven version override (build_version setting) 3 fully 2 partially
YAML-driven CMake FETCHCONTENT_SOURCE_DIR downloads 2 fully 3 partially
Midstream tag matcher in YAML settings 10 fully (subset of resolver) —
Missing file creation via YAML 1 fully —

1. Current Plugin Landscape

1.1 Hook Usage Distribution

Hook Plugin Count % of 62 Plugins
prepare_source 33 53%
get_resolver_provider 27 44%
build_wheel 21 34%
download_source 14 23%
update_extra_environ 11 18%
resolve_source 3 5%
build_sdist 4 6%
get_build_system_dependencies 2 3%
get_build_backend_dependencies 2 3%
get_build_sdist_dependencies 2 3%
get_install_dependencies_of_sdist 2 3%

1.2 Plugin Complexity Tiers

Tier 1 — Trivial (could be YAML only): 17 plugins

  • Resolver-only: deep_ep, kubeflow, litellm, llama_stack, mlflow_skinny, mlflow_tracing, mlserver, mlserver_lightgbm, mlserver_sklearn, mlserver_xgboost, pplx_kernels, tritonclient
  • PKG-INFO only: ibm_fms, userpath, cuda_pathfinder
  • Version override only: torchaudio, torchvision

Tier 2 — Low complexity (1–2 simple operations): 15 plugins

  • Source patching: amdsmi, certifi, docling, hf_xet, kfp, kornia_rs, tqdm_multiprocess, tpu_inference
  • Simple git source: nvidia_riva_client, tacozip, deep_gemm
  • Version+env: trl, torchao, faiss_cpu

Tier 3 — Medium complexity (multi-hook with custom logic): 16 plugins

  • Git source + dependency downloads: cmake, onnx, nvidia_cudnn_frontend, nixl, nixl_cu12, nixl_cu13, opencv_python_headless, symengine
  • Custom Rust vendoring: meson, outlines_core
  • Version-to-commit mapping: submodlib_py, tpu_info, vllm_hpu_extension
  • Custom build steps: flashinfer_python, llvmlite, pydantic_core

Tier 4 — High complexity (irreducible): 14 plugins

  • Full custom build pipelines: aotriton, pyarrow, tensorflow, tilelang, triton
  • Multi-variant hardware builds: torch, vllm, bitsandbytes
  • Custom resolvers: tensorflow_rocm, amdsmi (dynamic constraints)
  • Special builds: flit_core, mlflow, pypdfium2, flashinfer_python
  • Complex dependency management: vllm_neuron, nixl_cu12/cu13

2. Proposed Fromager Enhancements

2.1 YAML-Driven Git Tag Resolver (HIGH IMPACT)

Problem: 27 plugins implement get_resolver_provider, and 11 of these exist solely for this hook. Most just wire up GitLabTagProvider or GitHubTagProvider with a project path and optional matcher.

Current plugin pattern (repeated 11+ times):

def get_resolver_provider(ctx, req, sdist_server_url, include_sdists, include_wheels, **kwargs):
    if include_sdists:
        return resolver.GitLabTagProvider(
            project_path="/redhat/rhel-ai/core/mirrors/github/org/repo",
            constraints=ctx.constraints,
        )
    return resolver.default_resolver_provider(ctx, req, sdist_server_url, ...)

Proposed YAML setting:

# overrides/settings/package.yaml
resolver_dist:
  provider: gitlab_tags  # or "github_tags" or "pypi" (default)
  project_path: "/redhat/rhel-ai/core/mirrors/github/org/repo"  # for gitlab_tags
  # OR
  organization: "org"  # for github_tags
  repo: "repo"         # for github_tags
  tag_matcher: "midstream"  # built-in matchers: "standard", "midstream", or regex string
  tag_filter_asset: "vendored-deps"  # optional: filter tags by asset name prefix
  include_sdists: false
  include_wheels: true

Built-in tag matchers Fromager should support:

  1. "standard" — Default v1.2.3 / 1.2.3 pattern (already exists)
  2. "midstream" — ADR-114 pattern v{version}+rhai{N}[.{accelerator}] (used by 10 plugins)
  3. Custom regex string — e.g., "v(.+)-stable" (used by litellm, pplx_kernels)
  4. Callable — For truly complex cases (keep plugin hook as escape hatch)

Plugins eliminated: deep_ep, kubeflow, litellm, llama_stack, mlflow_skinny, mlflow_tracing, mlserver, mlserver_lightgbm, mlserver_sklearn, mlserver_xgboost, pplx_kernels, tritonclient (12 plugins)

Plugins simplified: aiter, deep_gemm, flashinfer_jit_cache, nixl, nixl_cu12, nixl_cu13, nvidia_cudnn_frontend, torchao, tilelang, vllm_neuron (10 plugins — resolver portion eliminated)

Implementation notes:

  • The create_midstream_matcher() function from package_plugins/utils.py would need to be ported to Fromager
  • Midstream matcher supports optional accelerator parameter and filter_by_accelerator flag
  • The tag_filter_asset option handles the mlflow pattern of filtering GitHub releases by attached assets

2.2 Auto-Detect and Generate PKG-INFO (MEDIUM IMPACT)

Problem: 16 plugins call ensure_pkg_info() in their prepare_source hook. For 3 plugins (ibm_fms, userpath, cuda_pathfinder), this is their only purpose.

Current pattern:

def prepare_source(ctx, req, source_filename, version):
    source_root_dir, is_new = sources.default_prepare_source(ctx, req, source_filename, version)
    if is_new:
        sources.ensure_pkg_info(source_root_dir, req, version)
    return source_root_dir, is_new

Proposed Fromager change:
Make default_prepare_source automatically call ensure_pkg_info when PKG-INFO is missing. This is already done in default_build_sdist, but by the time build_sdist runs, some tools (setuptools-scm) may have already failed during dependency resolution.

Specifically: In sources.default_prepare_source(), after prepare_new_source(), check if PKG-INFO exists. If not, call ensure_pkg_info(). This is safe because:

  • ensure_pkg_info only creates PKG-INFO if it doesn't exist
  • Having PKG-INFO present never breaks builds
  • It's needed for setuptools-scm fallback version detection
  • It must happen before dependency hooks run (not just before sdist)

Alternatively (conservative approach): Add a YAML setting:

# overrides/settings/package.yaml
source_options:
  ensure_pkg_info: true  # default: false, for backward compatibility

Plugins eliminated: ibm_fms, userpath, cuda_pathfinder (3 plugins)

Plugins simplified: 13 other plugins that call ensure_pkg_info in their prepare_source can remove that line

2.3 YAML-Driven Dependency Patching (MEDIUM IMPACT)

Problem: 9 plugins patch pyproject.toml, setup.cfg, or requirements.in to remove or modify runtime dependencies. Fromager already supports project_override.remove_build_requires for build dependencies, but not for install/runtime dependencies.

Current plugin patterns:

Pattern A — Remove install dependencies (docling, kfp, tpu_inference, vllm):

def prepare_source(ctx, req, source_filename, version):
    source_root_dir, is_new = sources.default_prepare_source(...)
    if is_new:
        utils.replace_lines(source_root_dir / "pyproject.toml", {
            utils.poetry_pkg("easyocr"): "",    # comment out dependency
            utils.poetry_pkg("rapidocr"): "",   # comment out dependency
        })
    return source_root_dir, is_new

Pattern B — Remove build dependency not in [build-system] (amdsmi):

# Remove 'clang' from [project] dependencies section
utils.replace_lines(source_root_dir / "pyproject.toml", {
    r'"clang",': "# clang removed",
})

Proposed YAML setting:

# overrides/settings/package.yaml
project_override:
  # Existing (already works):
  remove_build_requires:
    - cmake
  update_build_requires:
    - "setuptools>=69.0"

  # NEW: Remove install/runtime dependencies
  remove_install_requires:
    - easyocr
    - rapidocr-onnxruntime
    - clang

  # NEW: Update/add install dependencies
  update_install_requires:
    - "torchvision>=0.20,<0.21"  # replace version constraint

  # NEW: Remove optional/extra dependencies
  remove_extras_requires:
    dev:
      - pytest-benchmark
    ocr:
      - easyocr

Implementation: Fromager's pyproject.apply_project_override() (already called in prepare_new_source()) would be extended to handle these new keys. It already has the infrastructure for modifying pyproject.toml and setup.cfg.

Plugins eliminated: docling, kfp (2 plugins fully — their only purpose is dependency removal)

Plugins simplified: amdsmi, tpu_inference, vllm, vllm_neuron (4 plugins — dependency patching portion removed)

2.4 YAML-Driven Version Override (MEDIUM IMPACT)

Problem: 5 plugins exist solely or primarily to set BUILD_VERSION environment variable for Torch/Meta ecosystem packages. This is a well-understood, deterministic pattern.

Current plugin pattern:

# torchaudio.py, torchvision.py (identical)
def build_wheel(ctx, build_env, extra_environ, req, sdist_root_dir, build_dir, version):
    extra_environ["BUILD_VERSION"] = str(version)
    return wheels.default_build_wheel(ctx, build_env, extra_environ, req, sdist_root_dir, build_dir, version)
# trl.py
def build_wheel(...):
    extra_environ["PYTORCH_BUILD_VERSION"] = version.base_version
    extra_environ["PYTORCH_BUILD_NUMBER"] = str(version.post) if version.post else "0"
    return wheels.default_build_wheel(...)

Proposed YAML setting:

# overrides/settings/torchaudio.yaml
env:
  BUILD_VERSION: "${version}"  # NEW: support ${version} template variable

# OR more explicit:
build_version:
  BUILD_VERSION: "${version}"
  # For torch/trl:
  PYTORCH_BUILD_VERSION: "${version.base_version}"
  PYTORCH_BUILD_NUMBER: "${version.post:-0}"

Implementation: Extend Fromager's get_extra_environ() to support ${version}, ${version.base_version}, ${version.post} template variables in the env: section. Currently only ${VAR} (environment variable references) are supported.

Plugins eliminated: torchaudio, torchvision, trl (3 plugins)

Plugins simplified: torchao (version override portion removed), torch (BUILD_VERSION portion)

2.5 YAML-Driven CMake Dependency Downloads (MEDIUM IMPACT)

Problem: 5 plugins download external source archives during prepare_source for CMake FETCHCONTENT_SOURCE_DIR_* offline builds. The pattern is identical: download a tarball, extract it, set an environment variable pointing to it.

Current plugin pattern (repeated in cmake, onnx, nvidia_cudnn_frontend, symengine, nixl_cu12/cu13):

def prepare_source(ctx, req, source_filename, version):
    source_root_dir, is_new = sources.default_prepare_source(...)
    if is_new:
        # Download dependency
        tarball = utils.download_url(
            source_root_dir / ".deps",
            f"https://github.com/org/dep/archive/v{dep_version}.tar.gz",
            f"dep-{dep_version}.tar.gz",
        )
        # Extract
        shutil.unpack_archive(tarball, source_root_dir / ".deps")
    return source_root_dir, is_new

def update_extra_environ(ctx, req, version, sdist_root_dir, extra_environ, build_env):
    extra_environ["FETCHCONTENT_SOURCE_DIR_DEP"] = str(
        sdist_root_dir / ".deps" / f"dep-{dep_version}"
    )

Proposed YAML setting:

# overrides/settings/onnx.yaml
build_dependencies:
  - name: protobuf
    url: "https://github.com/protocolbuffers/protobuf/releases/download/v${dep_version}/protobuf-${dep_version}.tar.gz"
    version_from: "CMakeLists.txt"  # extract version from this file
    version_regex: 'set\(Protobuf_VERSION "([^"]+)"\)'
    extract_to: ".deps/"
    env_var: "FETCHCONTENT_SOURCE_DIR_PROTOBUF"

  - name: abseil
    url: "https://github.com/abseil/abseil-cpp/releases/download/${dep_version}/abseil-cpp-${dep_version}.tar.gz"
    version_from: ".deps/protobuf-${protobuf.version}/cmake/abseil-cpp.cmake"
    version_regex: 'set\(ABSL_TAG "([^"]+)"\)'
    extract_to: ".deps/"
    env_var: "FETCHCONTENT_SOURCE_DIR_ABSL"

Alternative (simpler) approach — list of downloads:

# overrides/settings/cmake.yaml
source_downloads:
  - url: "https://github.com/Kitware/CMake/releases/download/v3.31.6/cmake-3.31.6.tar.gz"
    destination: "build/cmake-3.31.6-source"
    env_var: "CMAKE_SOURCE_DIR"  # optional: set env var pointing to extracted dir

  # For packages needing version extracted from source files
  - url: "https://github.com/org/dep/archive/v${extract:CMakeLists.txt:set\\(DEP_VERSION \"([^\"]+)\"\\)}.tar.gz"
    destination: ".deps/"

Plugins eliminated: cmake (1 plugin — downloading CMake source is its only purpose)

Plugins simplified: onnx, nvidia_cudnn_frontend, symengine, nixl_cu12, nixl_cu13 (5 plugins — download portion removed)

Implementation complexity: Medium. The simple version (explicit URLs + destinations) is straightforward. The version-extraction-from-files feature adds complexity but handles a real pattern (onnx extracting protobuf version from CMakeLists.txt).

2.6 Auto-Create Missing Files (LOW IMPACT)

Problem: 1 plugin (tqdm_multiprocess) exists solely to create an empty requirements-dev.txt file that setup.py expects but the sdist doesn't include.

Proposed YAML setting:

# overrides/settings/tqdm_multiprocess.yaml
source_fixes:
  create_files:
    - path: "requirements-dev.txt"
      content: ""  # empty file

Plugin eliminated: tqdm_multiprocess (1 plugin)

Implementation complexity: Very low. Add a step in prepare_new_source() that creates specified files if they don't exist.

2.7 YAML-Driven Source Line Patching (LOW-MEDIUM IMPACT)

Problem: 10 plugins use utils.replace_lines() to make regex-based modifications to source files. While Fromager already has a patch system (overrides/patches/), these are often single-line changes that don't warrant full patch files (which are version-specific and fragile).

Current pattern:

utils.replace_lines(source_root_dir / "pyproject.toml", {
    r'"easyocr>=1.4"': "",
    r'rapidocr-onnxruntime': "",
})

Proposed YAML setting:

# overrides/settings/package.yaml
source_patches:
  - file: "pyproject.toml"
    replacements:
      - pattern: '"easyocr>=1.4"'
        replacement: ""
      - pattern: "rapidocr-onnxruntime"
        replacement: ""
  - file: "Cargo.toml"
    replacements:
      - pattern: 'features = \["require-simd"\]'
        replacement: 'features = []'
        arch_only: "s390x"  # optional: only apply on specific architectures

Note: This overlaps significantly with proposal 2.3 (remove_install_requires) for the dependency-removal use case. This more general facility would handle non-dependency patching cases like:

  • kornia_rs: Disabling SIMD features in Cargo.toml for s390x
  • hf_xet: Removing python-source from [tool.maturin]
  • deep_gemm: Patching __version__ in __init__.py

Plugins simplified: kornia_rs, hf_xet, deep_gemm, tpu_inference, amdsmi (5 plugins)

Implementation complexity: Medium. Need to handle regex safely, support architecture conditions, and integrate into prepare_new_source().

2.8 Version-to-Commit Mapping in YAML (LOW IMPACT)

Problem: 3 plugins (submodlib_py, tpu_info, vllm_hpu_extension) use resolve_source with VersionMap to map specific versions to git commit SHAs because the upstream repos have no version tags.

Current pattern:

VERSIONS = VersionMap({
    "abc123def": ("1.0.0", "https://gitlab.com/.../archive/abc123def/repo-abc123def.tar.gz"),
})

def resolve_source(ctx, req, sdist_server_url, **kwargs):
    return resolve_specifier(ctx, req, VERSIONS.get_version_info)

Proposed YAML setting:

# overrides/settings/submodlib_py.yaml
version_map:
  "1.0.0":
    commit: "abc123def456"
    url: "https://gitlab.com/.../archive/${commit}/repo-${commit}.tar.gz"
  "1.1.0":
    commit: "def789ghi012"
    url: "https://gitlab.com/.../archive/${commit}/repo-${commit}.tar.gz"

Plugins eliminated: submodlib_py (partially), tpu_info (partially), vllm_hpu_extension (partially)

Implementation complexity: Low-medium. Needs integration with the resolver system.

3. Fromager Internal Improvements (No YAML Changes)

3.1 Automatic Rust Vendor Ordering

Problem: 2 plugins (meson, outlines_core) override prepare_source solely to control the ordering of Rust vendoring relative to patch application. The default order is: unpack → patch → vendor Rust. These plugins need: unpack → vendor Rust → patch.

Current workaround:

def prepare_source(ctx, req, source_filename, version):
    source_root_dir = sources.unpack_source(...)
    vendor_rust.vendor_rust(...)  # vendor BEFORE patching
    sources.patch_source(...)     # then patch
    return source_root_dir, True

Proposed Fromager change:

# overrides/settings/meson.yaml
source_options:
  vendor_rust_before_patch: true  # default: false (current behavior)

Or better: Fromager could auto-detect when patches modify vendored Rust files and adjust ordering automatically.

Plugins eliminated: meson, outlines_core (if combined with other changes)

3.2 Monorepo Build Dir Auto-Detection

Problem: 12 packages use build_dir in YAML settings, and 2 plugins (triton, pyarrow) implement multiple hooks solely to redirect build operations to a subdirectory. Fromager already supports build_dir in YAML, but some plugins still override hooks because build_dir wasn't propagated to all hook default implementations.

Current state: Fromager's PackageBuildInfo.build_dir() method is available, and most default implementations accept a build_dir parameter. The issue is that some plugins override hooks just to pass the correct build_dir.

Proposed Fromager change: Ensure ALL default hook implementations automatically use pbi.build_dir() when available, so plugins never need to override hooks solely for build directory redirection.

3.3 Git Clone Improvements

Problem: 14 plugins implement download_source hooks. Many of these could be replaced by Fromager's built-in git clone support (via git+ URLs and git_options in YAML), but currently the built-in support doesn't handle:

  • Non-standard tag formats (e.g., r{version} for nvidia_riva_client, {build_number} for opencv)
  • GitLab authentication token injection
  • Pre-clone source modifications

Proposed Fromager changes:

# overrides/settings/nvidia_riva_client.yaml
download_source:
  url: "https://gitlab.com/.../archive/r${version}/repo-r${version}.tar.gz"
  # Tag format template already supported, but ensure 'r' prefix works
git_options:
  submodules: true
  tag_format: "r${version}"  # NEW: custom tag format for git clone

4. Impact Analysis

4.1 Plugins That Can Be Fully Eliminated

If all proposals in Section 2 were implemented in Fromager:

Plugin Eliminated By Current Purpose
deep_ep 2.1 (YAML resolver) GitLab tag resolver only
kubeflow 2.1 (YAML resolver) Midstream tag resolver only
litellm 2.1 (YAML resolver) Custom regex tag resolver only
llama_stack 2.1 (YAML resolver) Midstream tag resolver only
mlflow_skinny 2.1 (YAML resolver) Midstream tag resolver only
mlflow_tracing 2.1 (YAML resolver) Midstream tag resolver only
mlserver 2.1 (YAML resolver) Midstream tag resolver only
mlserver_lightgbm 2.1 (YAML resolver) Midstream tag resolver only
mlserver_sklearn 2.1 (YAML resolver) Midstream tag resolver only
mlserver_xgboost 2.1 (YAML resolver) Midstream tag resolver only
pplx_kernels 2.1 (YAML resolver) Custom regex tag resolver only
tritonclient 2.1 (YAML resolver) Midstream tag resolver only
ibm_fms 2.2 (auto PKG-INFO) PKG-INFO generation only
userpath 2.2 (auto PKG-INFO) PKG-INFO generation only
cuda_pathfinder 2.2 (auto PKG-INFO) PKG-INFO generation only
torchaudio 2.4 (version override) BUILD_VERSION only
torchvision 2.4 (version override) BUILD_VERSION only
trl 2.4 (version override) PYTORCH_BUILD_VERSION only
cmake 2.5 (CMake downloads) Download CMake source only
tqdm_multiprocess 2.6 (create files) Create empty file only
docling 2.3 (dep patching) Remove dependencies only
kfp 2.3 (dep patching) Remove dependencies only

Total: 22 plugins fully eliminated (35% of all plugins)

4.2 Plugins That Can Be Significantly Simplified

Plugin Hooks Remaining Hooks Eliminated
aiter update_extra_environ (GPU_ARCHS logic) get_resolver_provider, download_source, prepare_source
torchao update_extra_environ (SCM version) get_resolver_provider, download_source, prepare_source
deep_gemm prepare_source (version patching) get_resolver_provider, download_source
flashinfer_jit_cache — (may be fully eliminated) get_resolver_provider, download_source, prepare_source
nvidia_riva_client — (may be fully eliminated) download_source, prepare_source
kornia_rs — (may be fully eliminated with arch-conditional patching) prepare_source
hf_xet — (may be fully eliminated with TOML patching) prepare_source
onnx update_extra_environ (env vars) prepare_source (download portion)
nvidia_cudnn_frontend build_wheel (env var setup) get_resolver_provider, prepare_source (download portion)
amdsmi get_resolver_provider (dynamic constraints) prepare_source (dependency removal)
tpu_inference update_extra_environ prepare_source (patching portion)
vllm_neuron download_source (pre-tarball patching) get_resolver_provider

Total: ~12 plugins significantly simplified (19% of all plugins)

4.3 Plugins That Must Remain (Irreducible Complexity)

These plugins contain genuinely complex, package-specific logic that cannot be reasonably generalized:

Plugin Lines Reason
vllm ~815 6-variant build with 7+ external repo clones, extensive per-variant dependency patching
torch ~278 ROCm-specific AMD build steps, triton version fetching, complex dependency management
aotriton ~394 Full cmake/ninja build pipeline, custom wheel structure creation
tensorflow ~394 Bazel build system, custom .bazelrc generation, CUDA/ROCm configuration
tilelang ~324 cmake/ninja build, custom pyproject.toml generation, CUDA/ROCm configuration
pyarrow ~200 4-stage cmake/make build, CUDA variant support
triton ~180 Version-dependent build dir, LLVM version detection
bitsandbytes ~150 Multi-backend compilation (cpu/cuda/hip)
flashinfer_python ~120 Version-dependent build behavior, AOT compilation
symengine ~150 C++ library compilation + cmake
certifi ~50 Security patching (system cert store) — policy, not build logic
mlflow ~100 Yarn/Node.js web UI build
meson ~60 Custom Rust vendoring order (could be simplified with 3.1)
outlines_core ~80 Custom Rust vendoring order + aws-lc-sys patching
tensorflow_rocm ~100 Custom resolver scraping AMD repo
flit_core ~30 Bootstrap self-build
pypdfium2 ~80 System library integration
opencv_python_headless ~120 Non-standard tag format, ADE dependency pre-download
nixl_cu12 ~215 Meson subproject dependency downloads, .wrap file patching
nixl_cu13 ~215 Duplicate of nixl_cu12 (could share code but not eliminate)

5. Implementation Roadmap

Phase 1: Quick Wins (Low effort, high plugin reduction)

Estimated effort: 1–2 weeks of Fromager development

  1. Auto ensure_pkg_info in default_prepare_source (Proposal 2.2)

    • Eliminates: 3 plugins
    • Simplifies: 13 plugins
    • Effort: ~2 hours (add one check + function call)
    • Risk: Very low (additive, never breaks builds)

  2. ${version} template in env settings (Proposal 2.4)

    • Eliminates: 3 plugins
    • Simplifies: 2 plugins
    • Effort: ~4 hours (extend template engine)
    • Risk: Low

  3. YAML-driven dependency removal (Proposal 2.3 — remove_install_requires)

    • Eliminates: 2 plugins
    • Simplifies: 4 plugins
    • Effort: ~1 day (extend apply_project_override())
    • Risk: Low (builds on existing infrastructure)

Phase 2: Medium Effort (Significant plugin reduction)

Estimated effort: 2–4 weeks of Fromager development

  1. YAML-driven resolver configuration (Proposal 2.1)

    • Eliminates: 12 plugins
    • Simplifies: 10 plugins
    • Effort: ~1 week
    • Components:
      • Add provider, project_path, organization, repo to YAML schema
      • Add tag_matcher with built-in "standard", "midstream", regex options
      • Port create_midstream_matcher() to Fromager
    • Risk: Medium (resolver is core infrastructure)

  2. YAML-driven source downloads (Proposal 2.5)

    • Eliminates: 1 plugin
    • Simplifies: 5 plugins
    • Effort: ~3 days
    • Risk: Low-medium

  3. Create missing files from YAML (Proposal 2.6)

    • Eliminates: 1 plugin
    • Effort: ~2 hours
    • Risk: Very low

Phase 3: Refinements (Lower priority)

  1. Source line patching in YAML (Proposal 2.7)

    • Simplifies: 5 plugins
    • Effort: ~3 days
    • Risk: Medium (regex handling needs care)

  2. Rust vendor ordering control (Proposal 3.1)

    • Simplifies: 2 plugins
    • Effort: ~4 hours
    • Risk: Low

  3. Version-to-commit mapping (Proposal 2.8)

    • Simplifies: 3 plugins
    • Effort: ~2 days
    • Risk: Low

6. Quantitative Summary

Before vs. After (All Phases)

Metric Current After Phase 1 After Phase 2 After All Phases
Total plugins 62 54 (-8) 41 (-21) 40 (-22)
Resolver-only plugins 12 12 0 (-12) 0
Trivial plugins (< 20 lines of logic) 17 9 (-8) 0 (-17) 0
Entry points in pyproject.toml 80 72 (-8) 59 (-21) 58 (-22)
Lines of plugin code (estimated) ~6,500 ~6,000 ~4,800 ~4,500

Plugin Reduction by Proposal

Proposal 2.1 (YAML resolver)       ████████████████████████  12 eliminated, 10 simplified
Proposal 2.2 (auto PKG-INFO)       ██████████████████████    3 eliminated, 13 simplified
Proposal 2.3 (dep patching)        ████████████              2 eliminated, 4 simplified
Proposal 2.4 (version override)    ██████████                3 eliminated, 2 simplified
Proposal 2.5 (CMake downloads)     ████████████              1 eliminated, 5 simplified
Proposal 2.6 (create files)        ██                        1 eliminated
Proposal 2.7 (source patching)     ██████████                0 eliminated, 5 simplified
Proposal 2.8 (version-commit map)  ██████                    0 eliminated, 3 simplified
Proposals 3.x (internal)           ████                      0 eliminated, 2 simplified

7. Recommendations for Fromager Maintainers

Do First (Highest ROI)

  1. Auto ensure_pkg_info — Trivial change, immediately simplifies 16 plugins
  2. YAML resolver configuration — Eliminates 12 boilerplate plugins, largest single win
  3. ${version} in env templates — Small change, eliminates 3 plugins

Consider Carefully

  1. remove_install_requires — Useful but need to define scope (pyproject.toml only? setup.cfg? requirements files?)
  2. Source downloads — Generic feature but version extraction from source files adds complexity

Defer or Keep as Plugin Responsibility

  1. Multi-stage native builds (cmake/ninja/bazel) — Too varied to generalize
  2. Hardware-specific build logic — Inherently package-specific
  3. External repo cloning (vllm cloning cutlass, flash-attn, etc.) — Too complex and package-specific

Architectural Principle

The dividing line should be: If the customization can be expressed as data (URLs, patterns, names, flags), it belongs in YAML settings. If it requires procedural logic (conditional builds, multi-stage pipelines, dynamic computation), it belongs in plugins.

Appendix A: Plugin Inventory by Category

A.1 Resolver-Only Plugins (12) — All eliminable via Proposal 2.1

Plugin Provider Project/Org Matcher
deep_ep GitLabTagProvider mirrors/github/deepseek-ai/DeepEP standard
kubeflow GitLabTagProvider mirrors/github/kubeflow/sdk midstream
litellm GitLabTagProvider mirrors/github/BerriAI/litellm regex: v(.+)-stable
llama_stack GitLabTagProvider mirrors/github/meta-llama/llama-stack midstream
mlflow_skinny GitHubTagProvider mlflow/mlflow midstream
mlflow_tracing GitHubTagProvider mlflow/mlflow midstream
mlserver GitLabTagProvider mirrors/github/SeldonIO/MLServer midstream
mlserver_lightgbm GitLabTagProvider mirrors/github/SeldonIO/MLServer midstream
mlserver_sklearn GitLabTagProvider mirrors/github/SeldonIO/MLServer midstream
mlserver_xgboost GitLabTagProvider mirrors/github/SeldonIO/MLServer midstream
pplx_kernels GitLabTagProvider mirrors/github/ppl-ai/pplx-kernels regex: +downstream
tritonclient GitLabTagProvider mirrors/github/triton-inference-server/client midstream

A.2 PKG-INFO-Only Plugins (3) — All eliminable via Proposal 2.2

Plugin Additional Logic
ibm_fms None
userpath None
cuda_pathfinder Uses pbi.build_dir() for monorepo — needs ensure_pkg_info to respect build_dir

A.3 Version-Override-Only Plugins (3) — All eliminable via Proposal 2.4

Plugin Env Var Value
torchaudio BUILD_VERSION str(version)
torchvision BUILD_VERSION str(version)
trl PYTORCH_BUILD_VERSION + PYTORCH_BUILD_NUMBER version.base_version + post or "0"

A.4 Dependency-Removal-Only Plugins (2) — All eliminable via Proposal 2.3

Plugin File Modified Dependencies Removed
docling pyproject.toml easyocr, rapidocr-onnxruntime
kfp requirements.in all runtime deps

A.5 Complex Plugins Requiring Custom Logic (20) — Must remain as plugins

aotriton, bitsandbytes, certifi, flashinfer_python, flit_core, meson, mlflow, nixl_cu12, nixl_cu13, opencv_python_headless, outlines_core, pyarrow, pypdfium2, symengine, tensorflow, tensorflow_rocm, tilelang, torch, triton, vllm

Appendix B: Fromager YAML Settings Schema (Current)

For reference, these are the settings Fromager currently supports via YAML:

build_dir: str                           # Monorepo subdirectory
annotations: dict                        # Arbitrary key-value metadata
changelog: dict[str, list[str]]          # Version changelog
config_settings: dict                    # PEP 517 config settings
env: dict[str, str]                      # Environment variables (with ${VAR} templates)
download_source:
  url: str                               # Download URL (with ${version}, ${canonicalized_name})
  destination_filename: str              # Downloaded filename template
resolver_dist:
  sdist_server_url: str                  # Custom simple index URL
  include_sdists: bool                   # Resolve from sdists
  include_wheels: bool                   # Resolve from wheels
  ignore_platform: bool                  # Cross-platform resolution
  use_pypi_org_metadata: bool|null       # PyPI metadata preference
build_options:
  cpu_cores_per_job: int                 # CPU scaling factor
  memory_per_job_gb: float               # Memory scaling factor
  exclusive_build: bool                  # Build alone
  build_ext_parallel: bool               # Distutils parallelization
git_options:
  submodules: bool                       # Clone all submodules
  submodule_paths: list[str]             # Clone specific submodules
project_override:
  update_build_requires: list[str]       # Add/update build requirements
  remove_build_requires: list[str]       # Remove build requirements
  requires_external: list[str]           # System dependency metadata
variants:
  <variant_name>:
    annotations: dict
    env: dict[str, str]
    pre_built: bool                      # Use pre-built wheel
    wheel_server_url: str                # Custom wheel server

Appendix C: Proposed Additions to Fromager YAML Schema

# --- Proposal 2.1: YAML-driven resolver ---
resolver_dist:
  provider: str              # NEW: "pypi" (default), "gitlab_tags", "github_tags"
  project_path: str          # NEW: GitLab project path (for gitlab_tags)
  organization: str          # NEW: GitHub org (for github_tags)
  repo: str                  # NEW: GitHub repo (for github_tags)
  tag_matcher: str           # NEW: "standard", "midstream", or regex pattern
  tag_filter_asset: str      # NEW: Filter by release asset prefix

# --- Proposal 2.3: Dependency patching ---
project_override:
  remove_install_requires: list[str]     # NEW: Remove runtime dependencies
  update_install_requires: list[str]     # NEW: Add/update runtime dependencies

# --- Proposal 2.4: Version templates in env ---
env:
  BUILD_VERSION: "${version}"            # NEW: Support ${version} template
  # Also: ${version.base_version}, ${version.post}, ${version.major}, etc.

# --- Proposal 2.5: Source dependency downloads ---
source_downloads:                        # NEW section
  - url: str                             # Download URL
    destination: str                     # Extract destination (relative to source root)
    env_var: str                         # Optional: set env var pointing to extracted dir
    sha256: str                          # Optional: checksum verification

# --- Proposal 2.6: Missing file creation ---
source_fixes:                            # NEW section
  create_files:
    - path: str                          # File path relative to source/build dir
      content: str                       # File content

# --- Proposal 2.7: Source line patching ---
source_patches:                          # NEW section
  - file: str                            # File path relative to source root
    replacements:
      - pattern: str                     # Regex pattern
        replacement: str                 # Replacement string
        arch_only: str                   # Optional: only apply on specific arch

# --- Proposal 2.8: Version-to-commit mapping ---
version_map:                             # NEW section
  "<version>":
    commit: str                          # Git commit SHA
    url: str                             # Download URL (with ${commit} template)

# --- Proposal 3.1: Rust vendor ordering ---
source_options:                          # NEW section
  ensure_pkg_info: bool                  # Create PKG-INFO if missing (default: auto)
  vendor_rust_before_patch: bool         # Vendor Rust crates before patching

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    Feature

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions