[Kimchi-devel] [RFC] Host's repositories support

[Paulo Ricardo Paz Vital]

Hello guys. 

This is the RFC for the Host's repositories support (task "Register YUM,
apt, zypper repos" of 1.2 sprint 3).

The support will be provided by adding in the control/host.py a new
collection (Repositories), responsible to manage all repositories of the
system, and a new resource (Repository), responsible to operate with a
specific repository. All this management/operations will be transparent
to host's package management system, being provided by one of the new
back end classes.

The back end support provides 4 new classes:

1) Repositories (object): Class to represent and operate with
repositories information in Kimchi's perspective. It's transparent to
host's package management system, and can execute all operations
necessary: add repository, get all repositories list, get information
about one repository, update a repository, enable and disable a
repository and remove a repository. This class will load in run time the
necessary classes to work with the host's package management: YumRepo
for YUM systems based, AptRepo for APT systems based and ZypperRepo for
Zypper systems based;

2) YumRepo (object): Class to represent and operate with YUM
repositories. Loaded only on those systems that supports YUM (e.g.
Fedora and RHEL), it's responsible to connect, collect and provide
information of YUM repositories in the system. Also it's responsible to
create/delete the files in disk to maintain the repositories in system
after disconnection.

3) AptRepo (object): Class to represent and operate with APT
repositories. Loaded only on those systems that supports APT (e.g.
Debian and Ubuntu), it's responsible to connect, collect and provide
information of APT repositories in the system. Also it's responsible to
create/delete the files in disk to maintain the repositories in system
after disconnection.

4) ZypperRepo (object): Class to represent and operate with Zypper
repositories. Loaded only on those systems that supports Zypper (e.g.
OpenSuse), it's responsible to connect, collect and provide information
of Zypper repositories in the system. Also it's responsible to
create/delete the files in disk to maintain the repositories in system
after disconnection.

Bellow I present the REST API for the repositories support. 

### Collection: Host Repositories

**URI:** /host/repositories

**Methods:**

* **GET**: Retrieve a summarized list of all repositories available
* **POST**: Add a new repository
    * repo_id : Unique repository name for each repository, one word.
    * repo_name: Human-readable string describing the repository.
    * baseurl: URL to the repodata directory when "is_mirror" is false. 
Otherwise, it can be URL to the mirror system for YUM. Can be an
http://, ftp:// or file://  URL.
    * is_mirror *(optional)*: Set the given URI of baseurl as a mirror
list, instead of use baseurl in repository configuration.
    * url_args *(optional)*: Arguments to be passed to baseurl, like the
list of APT repositories provided by the same baseurl.
    * enabled *(optional)*: Indicates if repository should be included
as a package source:
        * false: Do not include the repository.
        * true: Include the repository.
    * gpgcheck *(optional)*: Indicates if a GPG signature check on the
packages gotten from repository should be performed:
        * false: Do not check GPG signature
        * true: Check GPG signature
    * gpgkey *(optional)*: URL pointing to the ASCII-armored GPG key
file for the repository. This option is used if yum needs a public key
to verify a package and the required key hasn't been imported into the
RPM database.

### Resource: Repository

**URI:** /host/repositories/*:repo-id*

**Methods:**

* **GET**: Retrieve the full description of a Repository
    * repo_id : Unique repository name for each repository, one word.
    * repo_type: Indicates which type of repository is:
        * yum: Indicates it is a YUM repository.
        * deb: Indicates it is a APT repository.
        * zyp: Indicates it is a Zypper repository.
    * repo_name: Human-readable string describing the repository.
    * baseurl: URL to the repodata directory when "is_mirror" is false. 
Otherwise, it can be URL to the mirror system for YUM. Can be an
http://, ftp:// or file://  URL.
    * url_args *(optional)*: Arguments to be passed to baseurl, like the
list of APT repositories provided by the same baseurl.
    * enabled *(optional)*: Indicates if repository should be included
as a package source:
        * false: Do not include the repository.
        * true: Include the repository.
    * gpgcheck *(optional)*: Indicates if a GPG signature check on the
packages gotten from repository should be performed:
        * false: Do not check GPG signature
        * true: Check GPG signature
    * gpgkey *(optional)*: URL pointing to the ASCII-armored GPG key
file for the repository. This option is used if yum needs a public key
to verify a package and the required key hasn't been imported into the
RPM database.
* **DELETE**: Remove the Repository
* **POST**: *See Repository Actions*
* **PUT**: update the parameters of existing Repository
    * repo_id *(otional)*: Unique repository name for each repository,
one word.
    * repo_name *(otional)*: Human-readable string describing the
repository.
    * baseurl *(optional)*: URL to the repodata directory when
"is_mirror" is false. Otherwise, it can be URL to the mirror system for
YUM. Can be an http://, ftp:// or file://  URL.
    * is_mirror *(optional)*: Set the given URI of baseurl as a mirror
list, instead of use baseurl in repository configuration.
    * url_args *(optional)*: Arguments to be passed to baseurl, like the
list of APT repositories provided by the same baseurl.
    * enabled *(optional)*: Indicates if repository should be included
as a package source:
        * false: Do not include the repository.
        * true: Include the repository.
    * gpgcheck *(optional)*: Indicates if a GPG signature check on the
packages gotten from repository should be performed:
        * false: Do not check GPG signature
        * true: Check GPG signature
    * gpgkey *(optional)*: URL pointing to the ASCII-armored GPG key
file for the repository. This option is used if yum needs a public key
to verify a package and the required key hasn't been imported into the
RPM database.

**Actions (POST):**

* enable: Enable the Repository as package source
* disable: Disable the Repository as package source