Add sphinx extensions for tree and issues (#219)

Adding sphinx extensions for sha references and issues

Signed-off-by: Alan Chiu <[email protected]>

For an explanation of how to fill out the fields, please see the relevant section
in [PULL_REQUESTS.md](https://github.com/envoyproxy/envoy/blob/master/PULL_REQUESTS.md)

Description: add sphinx extensions for tree and issues
Risk Level: low
Testing: local
Docs Changes: /docs
Release Notes:
[Optional Fixes #Issue]
[Optional Deprecated:]

Signed-off-by: JP Simard <[email protected]>

mobile/docs/conf.py

@@ -69,7 +69,9 @@ def setup(app):
 # ones.
 extensions = ['sphinxcontrib.httpdomain', 'sphinx.ext.extlinks', 'sphinx.ext.ifconfig']
 extlinks = {
+    'issue': ('https://github.com/lyft/envoy-mobile/issues/%s', ''),
     'repo': ('https://github.com/lyft/envoy-mobile/blob/{}/%s'.format(blob_sha), ''),
+    'tree': ('https://github.com/lyft/envoy-mobile/tree/%s', ''),
 }
 
 # Set up global substitutions

mobile/docs/root/development/performance/cpu_battery_impact.rst

@@ -5,10 +5,10 @@ Analysis of CPU/battery impact
 
 Modified versions of the "hello world" example apps were used to run these experiments:
 
-- `Android control app <https://github.com/lyft/envoy-mobile/tree/8636711/examples/kotlin/control>`_
-- `Android Envoy app <https://github.com/lyft/envoy-mobile/tree/8636711/examples/kotlin/hello_world>`_
-- `iOS control app <https://github.com/lyft/envoy-mobile/tree/f05d43f/examples/objective-c/control/control>`_
-- `iOS Envoy app <https://github.com/lyft/envoy-mobile/tree/f05d43f/examples/objective-c/xcode_variant/EnvoyObjc/EnvoyObjc>`_
+- :tree:`Android control app <8636711/examples/kotlin/control>`
+- :tree:`Android Envoy app <8636711/examples/kotlin/hello_world>`
+- :tree:`iOS control app <f05d43f/examples/objective-c/control/control>`
+- :tree:`iOS Envoy app <f05d43f/examples/objective-c/xcode_variant/EnvoyObjc/EnvoyObjc>`
 
 - **Control** - Made a request every ``200ms`` to an endpoint without Envoy compiled in the app.
 - **Envoy** - Made the same request at the same interval, but routed through an instance of Envoy.
@@ -21,7 +21,7 @@ Results
 iOS
 ---
 
-Valid through SHA `f05d43f <https://github.com/lyft/envoy-mobile/tree/f05d43f>`_.
+Valid through SHA :tree:`f05d43f <f05d43f>`.
 
 Envoy:
 
@@ -36,12 +36,12 @@ Control:
 - Battery: 1/20 Xcode Instruments score
 
 **Based on these results, memory usage is similar. However, CPU (and consequently battery) usage is very high.**
-The root cause has been identified and is being tracked in `issue 215 <https://github.com/lyft/envoy-mobile/issues/215>`_.
+The root cause has been identified and is being tracked in :issue:`issue 215 <215>`.
 
 Android
 -------
 
-Valid through SHA `8636711 <https://github.com/lyft/envoy-mobile/tree/8636711>`_.
+Valid through SHA :tree:`8636711 <8636711>`.
 
 TODO(buildbreaker): Update battery percentages
 
@@ -65,7 +65,7 @@ Experimentation method
 iOS
 ---
 
-The original investigation was completed as part of `this issue <https://github.com/lyft/envoy-mobile/issues/113>`_.
+The original investigation was completed as part of :issue:`this issue <113>`.
 
 For analysis, the `Energy Diagnostics tool from Xcode Instruments <https://developer.apple.com/library/archive/documentation/Performance/Conceptual/EnergyGuide-iOS/MonitorEnergyWithInstruments.html>`_
 was used.
@@ -124,14 +124,14 @@ iOS
 Envoy had a reasonable increase in memory usage of a few megabytes compared to control.
 
 CPU/battery usage, however, was much higher. After some digging, the largest contributor to this usage
-was `identified as a poller <https://github.com/lyft/envoy-mobile/issues/113#issuecomment-505676324>`_.
+was :issue:`identified as a poller <113#issuecomment-505676324>`.
 
-Upon further investigation, the `root cause was determined <https://github.com/lyft/envoy-mobile/issues/113#issuecomment-507425528>`_
+Upon further investigation, the :issue:`root cause was determined <113#issuecomment-507425528>`
 to be that ``poll_dispatch`` was being used by ``libevent`` instead of the much more performant ``kqueue``.
 Forcing ``libevent`` to use ``kqueue`` reduced the CPU usage **from >= 100% down to ~3%**.
-This issue and the subsequent fix are being tracked `here <https://github.com/lyft/envoy-mobile/issues/215>`_.
+This issue and the subsequent fix are being tracked :issue:`here <215>`.
 
-`We used Wireshark <https://github.com/lyft/envoy-mobile/issues/113#issuecomment-505673869>`_ to validate that
+:issue:`We used Wireshark <113#issuecomment-505673869>` to validate that
 network traffic was flowing through Envoy on the phone every ``200ms``, giving us confidence that there was
 no additional caching happening within ``URLSession``.