Merge tag 'v0.31.0'

Changes in synapse v0.31.0 (2018-06-06)
======================================

Most notable change from v0.30.0 is to switch to python prometheus library to improve system
stats reporting. WARNING this changes a number of prometheus metrics in a
backwards-incompatible manner. For more details, see
`docs/metrics-howto.rst <docs/metrics-howto.rst#removal-of-deprecated-metrics--time-based-counters-becoming-histograms-in-0310>`_.

Bug Fixes:

* Fix metric documentation tables (PR #3341)
* Fix LaterGuage error handling (694968f)
* Fix replication metrics (b7e7fd2)

Changes in synapse v0.31.0-rc1 (2018-06-04)
==========================================

Features:

* Switch to the Python Prometheus library (PR #3256, #3274)
* Let users leave the server notice room after joining (PR #3287)

Changes:

* daily user type phone home stats (PR #3264)
* Use iter* methods for _filter_events_for_server (PR #3267)
* Docs on consent bits (PR #3268)
* Remove users from user directory on deactivate (PR #3277)
* Avoid sending consent notice to guest users (PR #3288)
* disable CPUMetrics if no /proc/self/stat (PR #3299)
* Add local and loopback IPv6 addresses to url_preview_ip_range_blacklist (PR #3312) Thanks to @thegcat!
* Consistently use six's iteritems and wrap lazy keys/values in list() if they're not meant to be lazy (PR #3307)
* Add private IPv6 addresses to example config for url preview blacklist (PR #3317) Thanks to @thegcat!
* Reduce stuck read-receipts: ignore depth when updating (PR #3318)
* Put python's logs into Trial when running unit tests (PR #3319)

Changes, python 3 migration:

* Replace some more comparisons with six (PR #3243) Thanks to @NotAFile!
* replace some iteritems with six (PR #3244) Thanks to @NotAFile!
* Add batch_iter to utils (PR #3245) Thanks to @NotAFile!
* use repr, not str (PR #3246) Thanks to @NotAFile!
* Misc Python3 fixes (PR #3247) Thanks to @NotAFile!
* Py3 storage/_base.py (PR #3278) Thanks to @NotAFile!
* more six iteritems (PR #3279) Thanks to @NotAFile!
* More Misc. py3 fixes (PR #3280) Thanks to @NotAFile!
* remaining isintance fixes (PR #3281) Thanks to @NotAFile!
* py3-ize state.py (PR #3283) Thanks to @NotAFile!
* extend tox testing for py3 to avoid regressions (PR #3302) Thanks to @krombel!
* use memoryview in py3 (PR #3303) Thanks to @NotAFile!

Bugs:

* Fix federation backfill bugs (PR #3261)
* federation: fix LaterGauge usage (PR #3328) Thanks to @intelfx!

3 files changed, 82 insertions, 14 deletions

diff --git a/docs/code_style.rst b/docs/code_style.rst
index 9c52cb3182..62800b5b3e 100644
--- a/docs/code_style.rst
+++ b/docs/code_style.rst
@@ -16,7 +16,7 @@
       print("I am a fish %s" %
             "moo")
 
-      and this::
+    and this::
 
         print(
             "I am a fish %s" %
diff --git a/docs/metrics-howto.rst b/docs/metrics-howto.rst
index 8acc479bc3..5bbb5a4f3a 100644
--- a/docs/metrics-howto.rst
+++ b/docs/metrics-howto.rst
@@ -1,25 +1,47 @@
 How to monitor Synapse metrics using Prometheus
 ===============================================
 
-1. Install prometheus:
+1. Install Prometheus:
 
    Follow instructions at http://prometheus.io/docs/introduction/install/
 
-2. Enable synapse metrics:
+2. Enable Synapse metrics:
 
-   Simply setting a (local) port number will enable it. Pick a port.
-   prometheus itself defaults to 9090, so starting just above that for
-   locally monitored services seems reasonable. E.g. 9092:
+   There are two methods of enabling metrics in Synapse.
 
-   Add to homeserver.yaml::
+   The first serves the metrics as a part of the usual web server and can be
+   enabled by adding the "metrics" resource to the existing listener as such::
 
-     metrics_port: 9092
+     resources:
+       - names:
+         - client
+         - metrics
 
-   Also ensure that ``enable_metrics`` is set to ``True``.
+   This provides a simple way of adding metrics to your Synapse installation,
+   and serves under ``/_synapse/metrics``. If you do not wish your metrics be
+   publicly exposed, you will need to either filter it out at your load
+   balancer, or use the second method.
 
-   Restart synapse.
+   The second method runs the metrics server on a different port, in a
+   different thread to Synapse. This can make it more resilient to heavy load
+   meaning metrics cannot be retrieved, and can be exposed to just internal
+   networks easier. The served metrics are available over HTTP only, and will
+   be available at ``/``.
 
-3. Add a prometheus target for synapse.
+   Add a new listener to homeserver.yaml::
+
+     listeners:
+       - type: metrics
+         port: 9000
+         bind_addresses:
+           - '0.0.0.0'
+
+   For both options, you will need to ensure that ``enable_metrics`` is set to
+   ``True``.
+
+   Restart Synapse.
+
+3. Add a Prometheus target for Synapse.
 
    It needs to set the ``metrics_path`` to a non-default value (under ``scrape_configs``)::
 
@@ -31,7 +53,50 @@ How to monitor Synapse metrics using Prometheus
    If your prometheus is older than 1.5.2, you will need to replace
    ``static_configs`` in the above with ``target_groups``.
 
-   Restart prometheus.
+   Restart Prometheus.
+
+
+Removal of deprecated metrics & time based counters becoming histograms in 0.31.0
+---------------------------------------------------------------------------------
+
+The duplicated metrics deprecated in Synapse 0.27.0 have been removed.
+
+All time duration-based metrics have been changed to be seconds. This affects:
+
++----------------------------------+
+| msec -> sec metrics              |
++==================================+
+| python_gc_time                   |
++----------------------------------+
+| python_twisted_reactor_tick_time |
++----------------------------------+
+| synapse_storage_query_time       |
++----------------------------------+
+| synapse_storage_schedule_time    |
++----------------------------------+
+| synapse_storage_transaction_time |
++----------------------------------+
+
+Several metrics have been changed to be histograms, which sort entries into
+buckets and allow better analysis. The following metrics are now histograms:
+
++-------------------------------------------+
+| Altered metrics                           |
++===========================================+
+| python_gc_time                            |
++-------------------------------------------+
+| python_twisted_reactor_pending_calls      |
++-------------------------------------------+
+| python_twisted_reactor_tick_time          |
++-------------------------------------------+
+| synapse_http_server_response_time_seconds |
++-------------------------------------------+
+| synapse_storage_query_time                |
++-------------------------------------------+
+| synapse_storage_schedule_time             |
++-------------------------------------------+
+| synapse_storage_transaction_time          |
++-------------------------------------------+
 
 
 Block and response metrics renamed for 0.27.0
diff --git a/docs/server_notices.md b/docs/server_notices.md
index 221553b24d..58f8776319 100644
--- a/docs/server_notices.md
+++ b/docs/server_notices.md
@@ -5,7 +5,7 @@ Server Notices
 channel whereby server administrators can send messages to users on the server.
 
 They are used as part of communication of the server polices(see
-[consent_tracking.md](consent_tracking.md)), however the intention is that 
+[consent_tracking.md](consent_tracking.md)), however the intention is that
 they may also find a use for features such as "Message of the day".
 
 This is a feature specific to Synapse, but it uses standard Matrix
@@ -24,7 +24,10 @@ history; it will appear to have come from the 'server notices user' (see
 below).
 
 The user is prevented from sending any messages in this room by the power
-levels. They also cannot leave it.
+levels.
+
+Having joined the room, the user can leave the room if they want. Subsequent
+server notices will then cause a new room to be created.
 
 Synapse configuration
 ---------------------