We're going to need the db.Instance to keep some state, and for that to
work we need the same one passed around everywhere. Hence this moves the
leveldb-specific file opening stuff into the db package and exports the
dbInstance type.
Overwriting configuration files is likely to happen if a
user syncs their home directories across computers. In this
case, the biggest risk is that all nodes will end up with
the same certificate and thus Device ID.
When the model prepares a folder for syncing, it checks to
see if the configuration files this instance is using are
getting synced. If the are getting synced, and they aren't
getting ignored, a warning is emitted. The model is used
so that when a new folder is added dynamically, a warning
is also emitted.
This will not prevent a user from shooting themselves in
the foot, and will not cover all cases (e.g. symlinks).
It should provide _something_ for many users in this
situation to go on, though.
This implements a new debug/trace infrastructure based on a slightly
hacked up logger. Instead of the traditional "if debug { ... }" I've
rewritten the logger to have no-op Debugln and Debugf, unless debugging
has been enabled for a given "facility". The "facility" is just a
string, typically a package name.
This will be slightly slower than before; but not that much as it's
mostly a function call that returns immediately. For the cases where it
matters (the Debugln takes a hex.Dump() of something for example, and
it's not in a very occasional "if err != nil" branch) there is an
l.ShouldDebug(facility) that is fast enough to be used like the old "if
debug".
The point of all this is that we can now toggle debugging for the
various packages on and off at runtime. There's a new method
/rest/system/debug that can be POSTed a set of facilities to enable and
disable debug for, or GET from to get a list of facilities with
descriptions and their current debug status.
Similarly a /rest/system/log?since=... can grab the latest log entries,
up to 250 of them (hardcoded constant in main.go) plus the initial few.
Not implemented in this commit (but planned) is a simple debug GUI
available on /debug that shows the current log in an easily pasteable
format and has checkboxes to enable the various debug facilities.
The debug instructions to a user then becomes "visit this URL, check
these boxes, reproduce your problem, copy and paste the log". The actual
log viewer on the hypothetical /debug URL can poll regularly for new log
entries and this bypass the 250 line limit.
The existing STTRACE=foo variable is still obeyed and just sets the
start state of the system.
An error on opening .stignore will satisfy os.IsNotExist() and not be
reported. Other errors will be reported and stop the folder, including
is-not-exist errors from #include as these are passed through fmt.Errorf.
Also fixes minor issue where we would not print cause of folder stopping
to the log.
Also fixes minor issue with capitalization of errors.
