MB-48480: Add REST API to change alert limits.

This change adds a new POST REST endpoint /settings/alerts/limits
This end point supports the following paramters:
	1) maxOverheadPerc
	2) maxDiskUsedPerc
	3) maxIndexerRamPerc

Also adds a GET on /settings/alerts/limits

Change-Id: I2c4bbd7e96d7ec0a993e28ad4c261d643f136633
Reviewed-on: https://review.couchbase.org/c/ns_server/+/172470
Tested-by: Navdeep S Boparai <[email protected]>
Well-Formed: Build Bot <[email protected]>
Reviewed-by: Timofey Barmin <[email protected]>

Author: boparai11

src/menelaus_web.erl

@@ -362,6 +362,9 @@ get_action(Req, {AppRoot, IsSSL, Plugins}, Path, PathTokens) ->
                     {{[settings], read}, fun menelaus_web_settings:handle_settings_web/1};
                 ["settings", "alerts"] ->
                     {{[settings], read}, fun menelaus_alert:handle_settings_alerts/1};
+                ["settings", "alerts", "limits"] ->
+                    {{[settings], read},
+                     fun menelaus_web_alerts_srv:handle_settings_alerts_limits_get/1};
                 ["settings", "stats"] ->
                     {{[settings], read}, fun menelaus_web_settings:handle_settings_stats/1};
                 ["internal", "settings", "metrics" | PathRest] ->
@@ -629,6 +632,9 @@ get_action(Req, {AppRoot, IsSSL, Plugins}, Path, PathTokens) ->
                 ["settings", "alerts", "testEmail"] ->
                     {{[settings], write},
                      fun menelaus_alert:handle_settings_alerts_send_test_email/1};
+                ["settings", "alerts", "limits"] ->
+                    {{[settings], write},
+                     fun menelaus_web_alerts_srv:handle_settings_alerts_limits_post/1};
                 ["settings", "stats"] ->
                     {{[settings], write}, fun menelaus_web_settings:handle_settings_stats_post/1};
                 ["internal", "settings", "metrics" | PathRest] ->

src/menelaus_web_alerts_srv.erl

@@ -22,7 +22,8 @@
 -behaviour(gen_server).
 -define(SERVER, ?MODULE).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
-         terminate/2, code_change/3]).
+         terminate/2, code_change/3, handle_settings_alerts_limits_post/1,
+         handle_settings_alerts_limits_get/1]).
 
 -export([alert_keys/0, config_upgrade_to_70/1, config_upgrade_to_MORPHEUS/1]).
 
@@ -871,6 +872,38 @@ upgrade_alerts(EmailAlerts, Mutations) ->
             [{set, email_alerts, Result}]
     end.
 
+type_spec(undefined) ->
+    undefined.
+
+params() ->
+    [{"maxOverheadPerc", #{type => {int, 0, 100},
+                           cfg_key => max_overhead_perc}},
+     {"maxDiskUsedPerc", #{type => {int, 0, 100},
+                           cfg_key => max_disk_used}},
+     {"maxIndexerRamPerc", #{type => {int, 0, 100},
+                             cfg_key => max_indexer_ram}}].
+
+build_alert_limits() ->
+    case ns_config:search(alert_limits) of
+        false ->
+            [];
+        {value, Values} ->
+            Values
+    end.
+
+handle_settings_alerts_limits_get(Req) ->
+    menelaus_web_settings2:handle_get([], params(), fun type_spec/1,
+                                      build_alert_limits(), Req).
+
+handle_settings_alerts_limits_post(Req) ->
+    menelaus_web_settings2:handle_post(
+        fun (Params, Req2) ->
+            NewParams = [{Key, Val} || {[Key], Val} <- Params],
+            NewLimits = misc:update_proplist(build_alert_limits(), NewParams),
+            ns_config:set(alert_limits, NewLimits),
+            handle_settings_alerts_limits_get(Req2)
+        end, [], params(), fun type_spec/1, Req).
+
 -ifdef(TEST).
 %% Cant currently test the alert timeouts as would need to mock
 %% calls to the archiver