Callers that choose the context from configuration had to do it before
Initialize. That meant loading the config file and context store
themselves and handling --config a second time.
WithContextResolver runs a callback inside Initialize after the config
file and context store are loaded, but before telemetry and endpoint
initialization. A non-empty result replaces the selected context, an
empty result keeps normal selection, and an error aborts
initialization.
The API client and endpoint are resolved lazily, so they use the
overridden context.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Paweł Gronowski
b53372e86a