--- GLEP: 82 Title: Repository configuration file (layout.conf) Author: Michał Górny Type: Standards Track Status: Draft Version: 1.0 Created: 2021-05-19 Last-Modified: 2021-05-31 Post-History: 2021-05-19 Content-Type: text/x-rst --- Abstract ======== The ``metadata/layout.conf`` file format is specified as used by Portage and pkgcore. A standard set of configuration keys is described including the keys currently used in the Gentoo repository. Motivation ========== The ``metadata/layout.conf`` file was first added to the Gentoo repository in Oct 2011, to facilitate setting of hashes used in Manifest2 files. In Mar 2012, it was used to indicate the transition to the new ``md5-dict`` cache format. In Jul 2013, it started being used to indicate the repository's masters and effectively became obligatory for all repositories. Today, ``layout.conf`` is used for various repository configuration knobs that can be expressed as simple values and therefore do not justify adding new files to the repository. This primarily involves the configuration of development tools but also includes a few keys relevant to the behavior of the package manager. However, ``layout.conf`` is currently not covered by any formal specification. The PMS neglects its existence entirely, and the keys used are roughly defined by their first use of Portage or pkgcore. This GLEP aims to overcome this by providing a formal specification for the file, as well as an up-to-date list of permitted configuration keys. Specification ============= layout.conf file format ----------------------- Every ebuild repository must contain a ``metadata/layout.conf`` file. The file uses a line-oriented key-value format:: # comments are allowed key = value key2 = value2 Lines starting with a hash sign (``#``) represent comments and are ignored, as are lines consisting entirely of whitespace. Key can be any string and must not contain spaces. The exact form of value depends on the key. For some keys, the value is permitted to contain spaces, and it must not be quoted. In some cases an empty value is permitted. The whitespace between the elements is optional and is ultimately stripped. Every key must occur no more than once in the file. Configuration keys ------------------ This GLEP specifies a number of standard configuration keys. New keys may be added to it in the future. It is strongly recommended that any new keys are added to the specification before being used. The package manager can implement a subset of the listed keys. Unknown keys should be ignored. The following keys must be present in a ``layout.conf`` file: masters = Specifies the master repositories of this repository. For stand-alone repositories, this must be set to an empty value. Otherwise, it can list one or more repositories, separated by spaces. This key must be specified. Examples:: # most common case masters = gentoo # stand-alone repository masters = # multiple masters masters = gentoo python The following keys are optional: manifest-hashes = Specifies the list of hashes that should be used for new distfiles in the Manifest files. The development tools may create a subset of the specified hashes if it is not updating the checksums for the specified distfile, or does not support the hash in question. The hash names are specified in GLEP 74. [#GLEP74]_ The default set of hashes is implementation-defined. Example:: manifest-hashes = BLAKE2B SHA512 manifest-required-hashes = Specifies the list of hashes that must be used in Manifest files. The development tools must support all the hashes listed there, and update distfile checksums to use these hashes (refetching if necessary). This must be a subset of manifest-hashes. If not specified, all hashes from manifest-hashes (or the default set) are considered required. use-manifests = ``strict``, ``true`` or ``false`` Indicates the policy for creating and using Manifest files. If set to ``strict``, Manifest files are created and files are required to match digests found in Manifests. If set to ``true``, Manifests are created but digest mismatches are ignored. If set to ``false``, Manifests are not used at all. The default is ``strict``. update-changelog = ``true`` or ``false`` Indicates whether the development tools should write ChangeLog files. The default is ``false``. cache-formats = Specifies one or more cache formats used by the repository. The currently defined values are ``pms`` for the original format specified in the PMS and ``md5-dict`` for the md5-dict format introduced in Portage 2.2.0_alpha68. The default is implementation-defined. Examples:: # modern repo cache-formats = md5-dict # backwards compatibility case cache-formats = md5-dict pms eapis-deprecated = Specifies one or more EAPIs that are to be considered deprecated by the development tools for use in ebuilds, i.e. their use should trigger a warning. If not specified, no EAPIs are deprecated. Example:: eapis-deprecated = 0 1 2 3 4 eapis-banned = Specifies one or more EAPIs that are to be considered banned by the development tools for use in ebuilds, i.e. their use should be blocked. If not specified, no EAPIs are banned. repo-name = Specifies the repository name. If specified, it must be equal to the contents of ``profiles/repo_name``. If not specified, it defaults to the same value. Discouraged. aliases = Specified one or more additional names that can be used to reference the repository (e.g. in repository dependencies). If not specified, no aliases are defined. Example:: # gen2 is a fork of Gentoo that can be used in place of the Gentoo # repository repo-name = gen2 aliases = gentoo thin-manifests = ``true`` or ``false`` If enabled, Manifest files in the package directory must contain only ``DIST`` entries. If disabled, Manifest files in the package directory must list digests for all files found in the package directory and the files directory. The default is ``false``. sign-commits = ``true`` or ``false`` Indicates whether git commits are to be signed (using ``git commit --gpg-sign``. The default is ``false``. sign-manifests = ``true`` or ``false`` Indicates whether individual package Manifests should be PGP-signed. Note that this refers to the historical behavior of signing individual Manifests, not the GLEP 74 behavior of signing the top-level Manifest. [#GLEP74]_ The default is ``true`` if PGP signing is configured. properties-allowed = Specifies the list of ``PROPERTIES`` tokens that are permitted to be used in ebuilds. If present, the development tools should issue a warning if ``PROPERTIES`` contains any tokens that are not listed here. If not specified, all tokens are permitted. Example:: properties-allowed = live restrict-allowed = Same as properties-allowed, except for ``RESTRICT``. profile-formats = Specifies the format used by profiles and/or extensions to it. The default is ``pms`` indicating the format specified in the PMS. Other values are implementation-defined. Examples:: profile-formats = portage-1 profile-formats = portage-2 profile-set Complete example ---------------- The following is an example configuration for a git repository with Gentoo set as a master:: masters = gentoo # git: do not use ChangeLog, use thin, unsigned Manifests update-changelog = false thin-manifests = true sign-manifests = false # force the new md5-dict cache format cache-formats = md5-dict Rationale ========= This GLEP is written almost 10 years after ``layout.conf`` was originally introduced. This made it necessary to write it in such a way that both the modern and historical implementations in Portage and pkgcore, as well as the use in the Gentoo repository and a reasonably large subset of the other repositories would remain compliant. The historical default of assuming ``masters = gentoo`` when unspecified is omitted as it is not portable and verbosely deprecated for many years in Portage. All repositories are required to explicitly specify their masters, or an empty value if they are stand-alone. The default for Manifest hashes and cache formats are left to be implementation-defined, as the defaults changed over time and do not match between package managers. In particular, Portage attempts to autodetect the cache format currently used in a given repository. The repo-name key has been originally added as an alternative to ``profiles/repo_name``. However, the latter file is still required for PMS compliance. Furthermore, given that it is much easier to parse, there seems to be no appealing reason to work towards replacing that file. This means that for all practical reasons, the repo-name key is redundant and is listed here for completeness only. The profile-formats key has been introduced to permit Portage-specific extensions to the profile directory without having to introduce custom EAPIs. The exact extensions are considered outside the scope of this specification. Backwards Compatibility ======================= The existing implementations found in Portage and pkgcore conform to this specification, so does the ``metadata/layout.conf`` file found in the Gentoo repository. Reference Implementation ======================== The support for ``metadata/layout.conf`` is already a part of Portage and pkgcore. References ========== .. [#GLEP74] GLEP 74: Full-tree verification using Manifest files (https://www.gentoo.org/glep/glep-0074.html) Copyright ========= This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/4.0/.