Enhanced Package Installation with Improved Dependency Management and Extended Environment Configuration

[tiff-ritz]

Summary of Changes

This pull request introduces several enhancements and improvements to the buildpack-deb-packages project. The package installation process has been enhanced with the addition of support for default and configurable environment variables. Dependency management has been improved with better logic for handling special case packages that require additional package installation. The metadata used for caching has been improved with the addition of a timestamp Cache Management was improved with the introduction of an environment variable.

Detailed Changes

A tokio runtime has been introduced for asynchronous operations.

The package index creation process has been enhanced with the addition of a timestamp for updating and caching package sources. PACKAGE_CACHE_DAYS defines the number of days for which package cache is considered valid. The value of 0 will cause the cache to be recreated. Unit tests for package index creation functions have also been added.

Dependency management has been improved with the addition of support for special case constant defining packages and their required packages in order to cover all dependencies. Unit tests for dependency resolution functions have been added.

Error handling has been enhanced with the additional of new error types and messages for the new functionality. Unit tests for error handling functions have been added.

The package installation process has been enhanced with the addition of a timestamp for updating and caching packages. The PACKAGE_CACHE_DAYS environment variable has been introduced which helps control how frequently the package cache is refreshed to ensure the most up-to-date packages are used. Support for defining environment variables in the project.toml has been introduced. The package_env_vars constant and function has been added to define environment variables for specific packages. The logic for downloading and extracting package control.tar has been improved, and the execute_postinst_script function has been introduced to handle post-installation scripts. The logic for configuring environment variables for installed packages has been enhanced, and unit tests for package installation functions have been added.

The README.md has been updated to contain more documentation for the new features. Separate documentation has been created for special case map, default package environment variables, and configurable environment variables

Tests

Unit tests have been added for error handling functions in src/errors.rs, package installation functions in src/install_packages.rs, package index creation functions in src/create_package_index.rs, and dependency resolution functions in src/determine_packages_to_install.rs. Integration tests have been added in src/tests/integration_tests.rs.

Miscellaneous

Code formatting and cleanup have been applied across all modified files. Unnecessary comments and unused imports have been removed. Code readability has been improved by adding comments and structuring code logically.

New Features

The PACKAGE_ENV_VARS constant is a new feature in src/install_packages.rs. It defines environment variables for specific packages.

const PACKAGE_ENV_VARS: &[(&str, &[(&str, &str)])] = &[
    ("git", &[("GIT_EXEC_PATH", "{install_dir}/usr/lib/git-core"), ("GIT_TEMPLATE_DIR", "{install_dir}/usr/share/git-core/templates")]),
    ("ghostscript", &[("GS_LIB", "{install_dir}/var/lib/ghostscript")]),
    // define additional variable here
];

The SPECIAL_CASE_MAP constant is a new feature in src/determine_packages_to_install.rs. It maps special case packages to their required packages.

const SPECIAL_CASE_MAP: &[(&str, &[&str])] = &[
    ("portaudio19-dev", &["libportaudio2"]),
    ("7zip", &["7zip-standalone"]),
    // define additional packages here
];

The project.toml has been updated to support enhanced package installation and environment variable configuration.

schema-version = "0.2"

[com.heroku.buildpacks.deb-packages]
install = [
  "libgwenhywfar79",
  "libgwenhywfar-data",
  { name = "xmlsec1", skip_dependencies = true },
  "wget",
  "libvips",
  { name = "curl", force = true },
  { name = "git", env = {"GIT_EXEC_PATH" = "{install_dir}/usr/lib/git-core", "GIT_TEMPLATE_DIR" = "{install_dir}/usr/share/git-core/templates"}},
  { name = "ghostscript", env = {"GS_LIB" = "{install_dir}/var/lib/ghostscript"}},
]