Pulp

Introducing asyncio downloaders

Adds a HttpDownloader

• handles both synchronous and asynchronous downloads
• designed for subclassing to make custom downloader
• size validation works
• digest validation works
• has a well defined return interface DownloadResult

Adds a FileDownloader

Adds a BaseDownloader

Reworks the Factory

• Updates the Factory to use HttpDownloader and FileDownloader
• Handles http, https, and file
• Fully configures HttpDownloader with all importer settings including: ssl client and server options, basic auth, proxy, proxy_auth
• Can be reused with custom downloaders

Adds a GroupDownloader

• Downloads files in parallel but only return back to the use when any group of files are fully downloaded.
• Drivable with or with generators
• Constrains in-memory objects through generator use

General Updates

• Updates the importer to use the Factory
• Updates the docs to use docs from the new code

https://pulp.plan.io/issues/2951 closes #2951