It is sometimes necessary to defer initialization steps until the first actual usage
or until certain prerequisites have been met. For example, policy setting and
policy source registration should not occur during package initialization.
Instead, they should be deferred until the syspolicy package is actually used.
Additionally, any errors should be properly handled and reported, rather than
causing a panic within the package's init function.
In this PR, we add DeferredInit, to facilitate the registration and invocation
of deferred initialization functions.
Updates #12687
Signed-off-by: Nick Hill <mykola.khyl@gmail.com>
It is sometimes necessary to change a global lazy.SyncValue for the duration of a test. This PR adds a (*SyncValue[T]).SetForTest method to facilitate that.
Updates #12687
Signed-off-by: Nick Khyl <nickk@tailscale.com>
This adds the ability to "peek" at the value of a SyncValue, so that
it's possible to observe a value without computing this.
Updates tailscale/corp#17122
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I06f88c22a1f7ffcbc7ff82946335356bb0ef4622
Co-authored-by: Maisem Ali <maisem@tailscale.com>
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: David Anderson <danderson@tailscale.com>
