Previously network.py had its own idea of request IDs,
and each interface had its own which was sent on the wire.
The interface would jump through hoops to translate one
to the other.
This unifies them so that a message ID is passed when
queueing a request, in addition to the method and params.
network.py is now solely responsible for message ID management.
Apart from being simpler and clearer, this also should be faster
as there is much less data structure manipulation and rebuilding
happening.
On startup we make several connections simultaneously. Socket
maintenance code checks if we're not connected, and if not
switches to a connected interface if auto_connect.
Unfortunately this meant that we frequently didn't reconnect to
the prior good server on startup, because some other connection
would happen first and this code would decide to switch to it.
Instead, only switch if a connection attempt is not in progress.
If that times out at the O/S level the switch will happen.
Occurred when switching interfaces and there were unanswered
requests that need resending. This bug isn't new; it's been
there since at least 3rd June.
Remove interface communication out of blockchain.py
into network.py. network.py handles protocol requests
for headers and chunks. blockchain.py continues to
handle their analysis and verification.
If an interface provides a header chain that doesn't
connect, it is dismissed, as per a previous TODO comment.
This removes a thread and another source of timeouts.
I see no performance issues with this when truncating the
blockchain.
Rename 'result' to 'header' for clarity.
This allows us to distinguish between connecting and connected
state in interface.py (used to be done in network.py but that
had other issues).
This means we don't switch to a connecting server, and get_interfaces()
does not report connecting ones.
interfaces we have created.
Existing code has the concept of pending servers, where a connection
thread is started but has not sent a connection notification, and
and interfaces which have received the notification.
This separation caused a couple of minor bugs, and given the cleaner
semantics of unifying the two I don't think the separation is beneficial.
The bugs:
1) When stopping the network, we only stopped the connected interface
threads, not the pending ones. This would leave Python hanging
on exit if we don't make them daemon threads.
2) start_interface() did not check pending servers before starting
a new thread. Some of its callers did, but not all, so it was
possible to initiate two threads to one server and "lose" one thread.
Apart form fixing the above two issues, unification causes one more
change in semantics: we are now willing to switch to a connection
that is pending (we don't switch to failed interfaces). I don't
think that is a problem: if it times out we'll just switch
again when we receive the disconnect notification, and previously the
fact that an interface was in the interaces dictionary wasn't a
guarantee the connection was good anyway: we might not have processed
a pending disconnection notification.
Three places used to test for lagging and switch. Commonize the
code. We test for lagging before autoconnect so lagging
diagnostics are output if not auto-connect.
Lagging diagnotics moved to server_is_lagging().
1) For new proxy or protocol, restart the network and default to
the requested server.
2) Otherwise if we aren't using the requested server, switch to it
3) Otherwise choose a random server if the requested server is
stale and auto_connect is True
As switch_to_interface() now has another user, move the logic
there whereby we close the old interface in order to terminate
subscriptions, in order to have it in one place.
switch_to_random_interface used to do is_connected()
checks and remove interfaces when switching. This
is redundant: interfaces are only added to self.interfaces
once in is_connected() state from process_if_notification().
When they are disconnected, a notification is also received
and process_if_notification() performs the removal. Furthermore,
two other callers of switch_to_interface do not do explicit
is_connected() checks before calling it.
Traceback (most recent call last):
File "src/electrum/lib/network.py", line 411, in process_request
out['result'] = f(*params)
UnboundLocalError: local variable 'f' referenced before assignment
[Network] network error local variable 'f' referenced before assignment
Neil Booth
ThomasV
Eagle[TM]
ThomasV