There is some weird behaviour that seem to storm the update channel. And
our solution with a central map of update channels isnt particularly
elegant.
For now, replace all the complicated stuff with a simple channel that
checks roughly every 10s if the node is up to date. Only generate and
update if there has been changes.
This tries to make the same functions emit and consume the same type of
data all over the application.
If a function transform data, it should emit new data, not a pointer.
This commit adds some Prometheus metrics to /metrics in headscale.
It will add the standard go metrics, some automatic gin metrics and some
initial headscale specific ones.
Some of them has been added to aid debugging #97 (loop bug)
In the future, we can use the metrics to get rid of the sleep in the
integration tests by checking that our expected number of nodes has been
registered:
```
headscale_machine_registrations_total
```
This commit moves toNode to the bottom of the file, and adds a helper
function for lists of Machines to be converted.
It also adds string helpers for Machines and lists of machines.
Lastly it splits getPeers into getDirectPeers, which exist in the same
namespace, and getShared, which is nodes shared with the namespace.
getPeers is kept as a function putting together the two lists for
convenience.
This commit rewrites a bunch of the code to always use *Machine instead
of a mix of both, and a mix of tailcfg.Node and Machine.
Now we use *Machine, and if tailcfg.Node is needed, it is converted just
before needed.
If a node does not have an update channel, it is probably not connected,
clarify the log messages and make sure we dont print that it was updated
successfully (continue, not return)
Golangs built in HTTP server does not allow different HTTP timeout for
different types of handlers, so we cannot have a write timeout as we
attempt to do long polling (my bad).
See linked article.
Also removed redundant server declaration
