meta-stack-layering-support

Stack layering module with IPK package management system.

Maintainer:
Sreejith Ravi

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Directory Layout Sketch

├── CHANGELOG.md
├── classes
│   ├── base-deps-resolver.bbclass
│   ├── custom-rootfs-creation.bbclass
│   ├── gir-ipk-qemuwrapper.bbclass
│   ├── ipk-mode-support-base.bbclass
│   ├── kernel-devel.bbclass
│   ├── staging-ipk.bbclass
│   └── update-base-files-hostname.bbclass
├── conf
│   ├── include
│   │   └── pkg-resolver.conf
│   └── layer.conf
├── CONTRIBUTING.md
├── COPYING -> LICENSE
├── docs
│   ├── ipk-mode-support.md
│   ├── nativepkg-toolchain-prebuilt-mode.md
│   ├── prerequisite.md
│   ├── stack-layering-support.md
│   └── variables.md
├── lib
│   └── oe
│       └── sls_utils.py
├── LICENSE
├── NOTICE
├── README.md
└── recipes-core
    └── staging-ipk-pkgs.bb

Introduction

The meta-stack-layering-support layer enhances our Yocto-based (yotco) build process by enabling a modular, IPK-driven workflow. Instead of rebuilding every component from source in a monolithic fashion, this layer allows you to:

• Consume prebuilt IPKs from other stack layers without using package recipes. It also helps IPK consumption within the same stack layer when versions match — speeding up builds and saving disk space.
• Rebuild from source based on version changes, ensuring traceability and consistency.
• Assemble custom rootfs images by using both IPK mode and source mode packages.

Central to this functionality are several BBClasses that automate dependency resolution, metadata generation, and sysroot population. The sections below explain their roles and how to configure and use them.

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Table of Contents

• Key BBClasses & Their Roles
• Recipes (.bb)
• IPK Mode within stack layer
• Native Pkgs and Toolchain Prebuilt Mode
• Custom Rootfs Creation & IPK Dependency Resolution
• Configuration Variables
• Prerequisites
• Further Reading

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Key BBClasses & Their Roles

These classes drive the IPK-based layering logic. They are globally inherited or applied to specific recipes to manage metadata, staging, and installation.

• base-deps-resolver
  Parses DEPENDS and RDEPENDS in each recipe, generates IPK metadata files (.pcdeps, .shlibdeps), and creates hardlinks for required files in the recipe sysroot. This ensures broken or missing dependencies are captured and later resolved. It is globally inherited.

• staging-ipk
  Installs IPKs identified by base-deps-resolver into a shared staging directory. It uses caching flags (--no-install-recommends, --host-cache-dir) to minimize disk usage and speed up repeated operations.

• custom-rootfs-creation
  Manages installation of layer-provided IPKs into the final rootfs.

• gir-ipk-qemuwrapper
  Provides QEMU wrapper functions to support GObject Introspection tools when cross-staging IPKs.

• update-base-files-hostname
  Updates /etc/hostname and /etc/hosts entries in IPK-mode images to match the MACHINE name, ensuring consistency in network configuration.

• kernel-devel
  Generates a kernel-devel IPK containing kernel headers and build artifacts. This package enables out-of-tree kernel module builds without the full kernel source.

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Recipes (.bb)

Recipe Name	Inherits	Purpose
staging-ipk-pkgs.bb	staging-ipk	Applies staging-ipk logic to install IPK packages into individual recipe sysroots.

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Native Pkgs and Toolchain Prebuilt Mode

Purpose: Prebuild and reuse native packages within VM/Docker workflows.

In the stack layering model, we have separate build projects for each layer, along with an additional IA Assembler project for creating the full stack image. However, in all projects, the toolchain and native packages are built from source, which is a drawback of our layered model approach.

To address this, we have designed and integrated a new feature that allows consuming native packages and the toolchain from Docker/VM as prebuilts. This feature helps avoid building the toolchain and packages from source.

This approach standardizes the host toolchain and dramatically reduces rebuild times in containerized builds.

For a full walkthrough, see Native Pkgs and Toolchain Prebuilt Mode.

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Custom Rootfs Creation & IPK Dependency Resolution

Purpose: Create custom opkg configuration and generate version info for the packagegroups set in the IMAGE_INSTALL. This will support rootfs genration using both in IPK mode and source mode packages

For design details and log locations, see Stack Layering Support.

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IPK Mode within stack layer

Purpose: Dynamically switch between source builds and IPK consumption based on version continuity.

• Skip BitBake tasks and fetch prebuilt .ipk feeds when package versions align with previous releases.
• Trigger a rebuild from source if a package or any dependency experiences a major version bump, providing clear parse-time errors with guidance for resolution.

For detailed steps and examples, see IPK Mode within stack layer.

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Configuration Variables

Variable	Purpose
DEPLOY_IPK_FEED	Generate a local IPK feed (set to "1").
FEED_INFO_DIR	Directory for generated IPK feed metadata.
IPK_PKGGROUP_VER_INFO	Store packagegroup version details for final image metadata.
SYSROOT_IPK	Path to the common staging directory for IPK files.
IPK_CACHE_DIR	Directory to cache downloaded IPKs before staging.
IPKGCONF_LAYERING	Path to a custom opkg.conf used for stack-layering operations.
IPK_EXCLUSION_LIST	Space-separated list of packages to force source builds.
IPK_INCLUSION_LIST	Space-separated list of IPK packages to force install.
OPKG_ARCH_PRIORITY	Define IPK feed priority per architecture (format: <arch> = "<prio>").
DOCKER_NATIVE_SYSROOT	Path to the prebuilt toolchain and native packages.
KERNEL_IMAGEDEST	Kernel image destination folder which is required for prebuilt consumption.
FIRMWARE_IMAGEDEST	Firmware destination folder which is required for prebuilt consumption.
TARGET_BASED_IPK_STAGING	To create target based IPK staging instead of processing all avilable recipes.
GENERATE_NATIVE_PKG_PREBUILT	To generate version native prebuilts.
DEPENDS_ON_TARGET	To build pkg from source, if it depends on target package.
DEPENDS_VERSION_CHECK	To build the package from source, if a dependency's major version has changed.

Refer to the full variable guide: Variables.

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Prerequisites

Before enabling stack layering, verify with prerequisites checklist:

See the detailed prerequisites checklist: Prerequisite.

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Further Reading

• IPK Mode within stack layer: Version-based source vs. IPK builds.
  https://github.com/rdkcentral/meta-stack-layering-support/blob/develop/docs/ipk-mode-within-stack-layer.md
• Native Pkgs and Toolchain Prebuilt Mode: VM/Docker native package staging.
  https://github.com/rdkcentral/meta-stack-layering-support/blob/develop/docs/nativepkg-toolchain-prebuilt-mode.md
• Prerequisite: Yocto version and layer setup.
  https://github.com/rdkcentral/meta-stack-layering-support/blob/develop/docs/prerequisite.md
• Stack Layering Support: Core bbclass extensions and flow.
  https://github.com/rdkcentral/meta-stack-layering-support/blob/develop/docs/stack-layering-support.md
• Variables: Complete list of config variables.
  https://github.com/rdkcentral/meta-stack-layering-support/blob/develop/docs/variables.md