Package manager

[pmoura]

Work on a Logtalk package manager is in progress. This discussion is the preferred medium for discussing its goals and features and providing feedback. The current expectation is to have a beta version included in the upcoming 3.51.0 release.

Documentation preview

https://logtalk3.readthedocs.io/en/latest/devtools/packs.html

Main goals

• Portability: support for all Prolog backends
• Decentralized: support for multiple registries (e.g. official, public, company private, ...)
• Secure: checksums and signed packs, sanitized registry and pack specs

Main concepts

• Pack: a Logtalk (or Prolog) application or library
• Registry: a collection of pack specifications

Main features

• Add, pin, update, and delete registries
• Install, pin, update, and uninstall packs
• List available, installed, outdated, orphaned, and dependent packs
• Easy to express pack dependencies (names and versions)
• Support for git repos, archives, and local directories for registries
• Local and remote registry and pack specifications
• Support for specifying multiple pack versions
• Minimal specification of registries and packs (using Logtalk objects implementing pack and registry protocols)

Materialization

A Logtalk packs tool, included in the Logtalk distribution.

Timeline

1. Stable registry and pack specification protocols (enabling earlier user experimentation and feedback)
2. Stable implementation of registry handling
3. Basic pack handling functionality
4. Dependencies handing

Examples

• Registry specification (details subject to change):

:- object(logtalk_packs_registry,
	implements(registry_protocol)).

	:- info([
		version is 1:0:0,
		author is 'Paulo Moura',
		date is 2021-02-10,
		comment is 'Official Logtalk packs registry.'
	]).

	name('logtalk-packs').

	description('Official Logtalk packs registry').

	home('https://github.com/LogtalkDotOrg/logtalk-packs').

	clone('https://github.com/LogtalkDotOrg/logtalk-packs.git').

	archive('https://github.com/LogtalkDotOrg/logtalk-packs/archive/main.zip').

:- end_object.

• Pack specification (details subject to change):

:- object(lflat_pack,
	implements(pack_protocol)).

	:- info([
		version is 1:0:0,
		author is 'Paulo Moura',
		date is 2021-02-07,
		comment is 'Pack manifest file for L-FLAT - Logtalk Formal Language and Automata Toolkit.'
	]).

	name(lflat).

	description('L-FLAT - Logtalk Formal Language and Automata Toolkit').

	license('MIT').

	home('https://github.com/l-flat/lflat').

	version(
		2:0:2,
		stable,
		'https://github.com/l-flat/lflat/archive/refs/tags/v2.0.2.tar.gz',
		sha256 - '8774b3863efc03bb6c284935885dcf34f69f115656d2496a33a446b6199f3e19',
		[logtalk >= 3:36:0],
		all
	).

:- end_object.

[hnbeck]

Hi,

sounds good. This is the right context to ask something I want ask a long time. How to arrange source code such that packages are supported best. To be more concrete:

My app has code for handling OpenDrive files, writing xgml Graph files, communication. It is all part of my code, my one application. Now, how should I structure the code such that OpeDrive, xgml parts etc. could be coupled out later as an own package (or library) usable by others? And this question is even more valid in the context of the package manager to come :)

Cheers

Hans

[hnbeck]

Yes, exactly. At the moment, one class per file. Thanks for the hint related to Logtalk code_metrics tool

Cherrs

Hans

[hnbeck]

Hi Paulo,

regarding to the new package manger, does it require a special layout of a GitHub repository, for example main loader file and package file in root dir or whatever ? (BTW Its on my todo list to read the new docs in detail :)

[pmoura]

The following section in the documentation preview (which reflects the current Logtalk git version) includes a directory layout example:

https://logtalk3.readthedocs.io/en/latest/devtools/packs.html#registry-specification

Btw, the current Logtalk git version includes an improved version of the packs tool. The plan is to release a new Logtalk stable version later this month with the improved tool (its API is stable but test coverage is a WIP).

[pmoura]

P.S. The tool supports registries::lint/0 and packs::lint/0 predicates so that you can check if your registry and pack definitions are up-to-specs.

[hnbeck]

Super, thanks :)

Cheers

Hans

[pmoura]

Implemented one of the safety measures today. Registry loader files and registry/pack specification files and objects are filtered using Logtalk's term-expansion mechanism to ensure that only the expected terms are actually loaded and no unexpected directive goals are called. If you're curious, the current definitions of the hook objects are here.

[pmoura]

Also got basic functionality (adding a registry, installing a pack, ...) working on Windows 10 this weekend.

[pmoura]

Good progress implementing the package manager. Implemented functionality includes:

• add, update, clean, delete, and query registries
• install, pin, update, clean, delete, and query packs

Currently missing functionality includes:

• pack dependencies handling

Current version supports Linux, macOS, and Windows. But limited testing so far. To try out the current version, checkout the packs branch of the logtalk3 repo and start with the documentation at tools/packs/NOTES.md.

Stable pack registries (more to come):

https://github.com/LogtalkDotOrg/talkshow

Feedback most welcome.

[pmoura]

Indeed the registry URL must end with either a ​.git​  or an archive extension (except when using a file:// URL for a local directory). That's in the API documentation for the predicate ​add/3​ predicate but not highlighted in the ​packs​ tool overview. Pushed documentation updates.

[pmoura]

Added a registries::add/1 predicate to simplify the most common cases (for registry users, a registry made available as a git repo; for registry developers, a registry made available as a local directory).

[pmoura]

A list of publicly available Logtalk and Prolog pack registries is available at:

https://github.com/LogtalkDotOrg/pack-registries

[pmoura]

All pack dependency operators (which use all the standard term comparison operators) are now implemented in the current git version. Support for range dependencies (e.g. [reg::foo @>= 2.1, reg::foo < 3]) is also implemented.

[pmoura]

Basic support for defining, saving, and restoring virtual environments is now implemented. An overview of the new functionality is available at:
https://logtalk3.readthedocs.io/en/latest/devtools/packs.html#virtual-environments