Revert "Merge pull request #3066 from matrix-org/rav/remove_redundant_metrics"

We aren't ready to release this yet, so I'm reverting it for now.

This reverts commit d1679a4ed7947b0814e0f2af9b888a16c588f1a1, reversing
changes made to e089100c6231541c446e37e157dec8feed02d283.

5 files changed, 52 insertions, 28 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 5fbad54427..38372381ac 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,12 +1,3 @@
-Changes in synapse v0.28.0 (2018-xx-xx)
-=======================================
-
-As previously advised, this release removes a number of redundant Prometheus
-metrics. Administrators may need to update their dashboards and alerting rules
-to use the updated metric names, if they have not already done so. See
-`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
-for more details.
-
 Changes in synapse v0.27.2 (2018-03-26)
 =======================================
 
diff --git a/UPGRADE.rst b/UPGRADE.rst
index 39a16b1c0c..f6bb1070b1 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -52,7 +52,7 @@ Upgrading to $NEXT_VERSION
 ====================
 
 This release expands the anonymous usage stats sent if the opt-in
-``report_stats`` configuration is set to ``true``. We now capture RSS memory
+``report_stats`` configuration is set to ``true``. We now capture RSS memory 
 and cpu use at a very coarse level. This requires administrators to install
 the optional ``psutil`` python module.
 
@@ -60,13 +60,6 @@ We would appreciate it if you could assist by ensuring this module is available
 and ``report_stats`` is enabled. This will let us see if performance changes to
 synapse are having an impact to the general community.
 
-This release also removes a number of redundant Prometheus metrics.
-Administrators may need to update their dashboards and alerting rules to use
-the updated metric names, if they have not already done so. See
-`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
-for more details.
-
-
 Upgrading to v0.15.0
 ====================
 
diff --git a/docs/metrics-howto.rst b/docs/metrics-howto.rst
index 5e2d7c52ec..8acc479bc3 100644
--- a/docs/metrics-howto.rst
+++ b/docs/metrics-howto.rst
@@ -34,17 +34,6 @@ How to monitor Synapse metrics using Prometheus
    Restart prometheus.
 
 
-Deprecated metrics removed in 0.28.0
-------------------------------------
-
-Synapse 0.28.0 removes all of the metrics deprecated by 0.27.0, which are those
-listed under "Old name" below. This has been done to reduce the bandwidth used
-by gathering metrics and the storage requirements for the Prometheus server, as
-well as reducing CPU overhead for both Synapse and Prometheus.
-
-Administrators should update any alerts or monitoring dashboards to use the
-"New name" listed below.
-
 Block and response metrics renamed for 0.27.0
 ---------------------------------------------
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index ac75206ef5..64e083ebfc 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -47,6 +47,17 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 response_count = metrics.register_counter(
     "response_count",
     labels=["method", "servlet", "tag"],
+    alternative_names=(
+        # the following are all deprecated aliases for the same metric
+        metrics.name_prefix + x for x in (
+            "_requests",
+            "_response_time:count",
+            "_response_ru_utime:count",
+            "_response_ru_stime:count",
+            "_response_db_txn_count:count",
+            "_response_db_txn_duration:count",
+        )
+    )
 )
 
 requests_counter = metrics.register_counter(
@@ -62,24 +73,39 @@ outgoing_responses_counter = metrics.register_counter(
 response_timer = metrics.register_counter(
     "response_time_seconds",
     labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_time:total",
+    ),
 )
 
 response_ru_utime = metrics.register_counter(
     "response_ru_utime_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_ru_utime:total",
+    ),
 )
 
 response_ru_stime = metrics.register_counter(
     "response_ru_stime_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_ru_stime:total",
+    ),
 )
 
 response_db_txn_count = metrics.register_counter(
     "response_db_txn_count", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_db_txn_count:total",
+    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, when processing
 # this request
 response_db_txn_duration = metrics.register_counter(
     "response_db_txn_duration_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_db_txn_duration:total",
+    ),
 )
 
 # seconds spent waiting for a db connection, when processing this request
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index c3d8237e8f..e4b5687a4b 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -31,28 +31,53 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 block_counter = metrics.register_counter(
     "block_count",
     labels=["block_name"],
+    alternative_names=(
+        # the following are all deprecated aliases for the same metric
+        metrics.name_prefix + x for x in (
+            "_block_timer:count",
+            "_block_ru_utime:count",
+            "_block_ru_stime:count",
+            "_block_db_txn_count:count",
+            "_block_db_txn_duration:count",
+        )
+    )
 )
 
 block_timer = metrics.register_counter(
     "block_time_seconds",
     labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_timer:total",
+    ),
 )
 
 block_ru_utime = metrics.register_counter(
     "block_ru_utime_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_ru_utime:total",
+    ),
 )
 
 block_ru_stime = metrics.register_counter(
     "block_ru_stime_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_ru_stime:total",
+    ),
 )
 
 block_db_txn_count = metrics.register_counter(
     "block_db_txn_count", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_db_txn_count:total",
+    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, in this block
 block_db_txn_duration = metrics.register_counter(
     "block_db_txn_duration_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_db_txn_duration:total",
+    ),
 )
 
 # seconds spent waiting for a db connection, in this block