Our context package predates the establishment of current best practices
regarding context usage and it shows. It encourages bad practices such
as using contexts to propagate non-request-scoped values like the
application version and using string-typed keys for context values. Move
the package internal to remove it from the API surface of
distribution/v3@v3.0.0 so we are free to iterate on it without being
constrained by compatibility.
Signed-off-by: Cory Snider <csnider@mirantis.com>
Back in the before time, the best practices surrounding usage of Context
weren't quite worked out. We defined our own type to make usage easier.
As this packaged was used elsewhere, it make it more and more
challenging to integrate with the forked `Context` type. Now that it is
available in the standard library, we can just use that one directly.
To make usage more consistent, we now use `dcontext` when referring to
the distribution context package.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
You shouldn't have to import both:
github.com/docker/distribution/context
golang.org/x/net/context
just to use the distribution tools and implement the distribution interfaces.
By pulling the Context interface from golang.org/x/net/context into the
context package within the distribution project, you no longer have to import
both packages.
Note: You do not have to change anything anywhere else yet! All current uses
of both packages together will still work correctly because the Context
interface from either package is identical.
I've also made some other minor changes:
- Added a RemoteIP function. It's like RemoteAddr but discards the port suffix
- Added `.String()` to the response duration context value so that JSON log
formatting shows human-parseable duration and not just number of nano-seconds
- Added WithMapContext(...) to the context package. This is a useful function
so I pulled it out of the main.go in cmd/registry so that it can be used
elsewhere.
Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
The new context package supports context-aware logging, integrating with
logrus. Several utilities are provided to associate http requests with a
context, ensuring that one can trace log messages all the way through a
context-aware call stack.
A full description of this functionality is available in doc.go.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
