Allow health checkers to abort if the request context is canceled.
Modify the checkers to respect context cancelation and return wrapped
errors so the caller of CheckStatus() would be able to discriminate true
failed checks from checks which were aborted because the context became
done.
Signed-off-by: Cory Snider <csnider@mirantis.com>
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>
Go 1.13 and up enforce import paths to be versioned if a project
contains a go.mod and has released v2 or up.
The current v2.x branches (and releases) do not yet have a go.mod,
and therefore are still allowed to be imported with a non-versioned
import path (go modules add a `+incompatible` annotation in that case).
However, now that this project has a `go.mod` file, incompatible
import paths will not be accepted by go modules, and attempting
to use code from this repository will fail.
This patch uses `v3` for the import-paths (not `v2`), because changing
import paths itself is a breaking change, which means that the
next release should increment the "major" version to comply with
SemVer (as go modules dictate).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Also, add timeout and status code parameters to the HTTP checker, and
remove the threshold parameter for the file checker.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Update docs.
Change health_test.go tests to create their own registries and register
the checks there. The tests now call CheckStatus directly instead of
polling the HTTP handler, which returns results from the default
registry.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Add a section to the config file called "health". Within this section,
"filecheckers" and "httpcheckers" list checks to run. Each check
specifies a file or URI, a time interval for the check, and a threshold
specifying how many times the check must fail to reach an unhealthy
state.
Document the new options in docs/configuration.md.
Add unit testing for both types of checkers. Add an UnregisterAll
function in the health package to support the unit tests, and an
Unregister function for consistency with Register.
Fix a string conversion problem in the health package's HTTP checker.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
