Re: [PATCH 6/6] doc/technical_overview: Describe binary cache

[Henning Schild <henning.schild@siemens.com>]

This should be done along the way in every single patch, not afterwards.

Henning

Am Sun, 27 Aug 2017 18:13:39 +0300
schrieb Alexander Smirnov <asmirnov@ilbers.de>:

> Describe Isar binary cache feature.
> 
> Signed-off-by: Alexander Smirnov <asmirnov@ilbers.de>
> ---
>  doc/technical_overview.md | 59
> +++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 55
> insertions(+), 4 deletions(-)
> 
> diff --git a/doc/technical_overview.md b/doc/technical_overview.md
> index 20e08b4..b3265dc 100644
> --- a/doc/technical_overview.md
> +++ b/doc/technical_overview.md
> @@ -100,6 +100,43 @@ Target filesystem lifecycle can be described as
> following:
>   - According to the list of custom packages in bitbake recipes, the
> initial filesystem will be populated by successfully built packages.
>  
> +## 2.5 Binary Cache
> +
> +As mentioned above, apart from fetching binary packages from
> upstream apt +repositories, Isar is able to build custom packages
> from sources. To simplify +further custom packages management, Isar
> implements binary caching. +
> +Binary cache is a typical apt repository created by Isar to store
> newly built +packages. This repository has mainly two goals:
> +
> + - Simplify image filesystem populating and distributing binary
> packages to
> +   other systems.
> +
> + - Reuse these binaries in next builds to avoid re-building from the
> +   scratch everytime.
> +
> +Current Isar tree provides default cache repository: `meta-isar-bin`.
> +Isar binary cache is described by the following files:
> +
> + - `meta-isar-bin/conf/layer.conf`
> +
> + - `meta-isar-bin/files/distributions.in`
> +
> +After system build is complete, this repo contains binary packages
> for all the +distros and architectures, requested in multiconfig. So
> this folder can be +published and used as apt repo for already
> installed systems. +
> +An important note, that Isar creates local repositories using
> dedicated Debian +tool reprepro. This tool takes care about:
> +
> + - Maintenance of multiple architectures and distros.
> +
> + - Internal packages database management.
> +
> + - Repo signatures management.
> +
> + - Requests about available packages in repo (name, version etc...).
> +
>  # 3 Isar Internal Processes
>  
>  ## 3.1 General Overview
> @@ -174,10 +211,17 @@ contain debian folder. The build process is
> implemented in 
>     3. Run dpkg-buildpackage
>  
> -4. Task `do_install`: install successfully built packages
> +4. Further package processing depends on binary cache option:
> +
> +   1. Task `do_install_to_deploy`: install successfully built
> packages if
> +   binary cache is disabled:
>     `${BUILDCHROOT_DIR}/home/build/${PN}/*.deb` to deploy directory
>     `${DEPLOY_DIR_DEB}`
>  
> +   2. Task `do_install_to_cache`: install successfully built
> packages to
> +   binary cache repository:
> +   `${BUILDCHROOT_DIR}/home/build/${PN}/*.deb` to `${DIR_CACHE}`
> +
>  ## 3.5 Populate Target Filesystem
>  
>  Each target image can be extended by custom packages listed in
> IMAGE_INSTALL @@ -185,11 +229,18 @@ variable. Task `do_populate`
> performs the following: 
>  1. Parse IMAGE_INSTALL variable.
>  
> -2. Find respective packages in `${DEPLOY_DIR_DEB}`.
> +2. Further steps depends in binary cache option.
> +If binary cache is disabled:
> +
> +   1. Find respective packages in `${DEPLOY_DIR_DEB}`.
> +
> +   2. Copy packages to deb folder in dedicated target filesystem.
> +
> +   3. Execute dpkg command in chroot for all the copied packages.
>  
> -3. Copy them to deb folder in dedicated target filesystem.
> +If binary cache is enabled:
>  
> -4. Execute dpkg command in chroot for all the copied packages.
> +   1. Call apt-get install in chroot in target image filesystem.
>  
>  ## 3.6 Generate Bootable Image
>