Comment out most options in the generated config. (#4863)

Make it so that most options in the config are optional, and commented out in
the generated config.

The reasons this is a good thing are as follows:

* If we decide that we should change the default for an option, we can do so,
  and only those admins that have deliberately chosen to override that option
  will be stuck on the old setting.

* It moves us towards a point where we can get rid of the super-surprising
  feature of synapse where the default settings for the config come from the
  generated yaml.

* It makes setting up a test config for unit testing an order of magnitude
  easier (see forthcoming PR).

* It makes the generated config more consistent, and hopefully easier for users
  to understand.

1 files changed, 15 insertions, 8 deletions

diff --git a/synapse/config/captcha.py b/synapse/config/captcha.py
index d25196be08..f7eebf26d2 100644
--- a/synapse/config/captcha.py
+++ b/synapse/config/captcha.py
@@ -18,11 +18,16 @@ from ._base import Config
 class CaptchaConfig(Config):
 
     def read_config(self, config):
-        self.recaptcha_private_key = config["recaptcha_private_key"]
-        self.recaptcha_public_key = config["recaptcha_public_key"]
-        self.enable_registration_captcha = config["enable_registration_captcha"]
+        self.recaptcha_private_key = config.get("recaptcha_private_key")
+        self.recaptcha_public_key = config.get("recaptcha_public_key")
+        self.enable_registration_captcha = config.get(
+            "enable_registration_captcha", False
+        )
         self.captcha_bypass_secret = config.get("captcha_bypass_secret")
-        self.recaptcha_siteverify_api = config["recaptcha_siteverify_api"]
+        self.recaptcha_siteverify_api = config.get(
+            "recaptcha_siteverify_api",
+            "https://www.recaptcha.net/recaptcha/api/siteverify",
+        )
 
     def default_config(self, **kwargs):
         return """\
@@ -31,21 +36,23 @@ class CaptchaConfig(Config):
 
         # This Home Server's ReCAPTCHA public key.
         #
-        recaptcha_public_key: "YOUR_PUBLIC_KEY"
+        #recaptcha_public_key: "YOUR_PUBLIC_KEY"
 
         # This Home Server's ReCAPTCHA private key.
         #
-        recaptcha_private_key: "YOUR_PRIVATE_KEY"
+        #recaptcha_private_key: "YOUR_PRIVATE_KEY"
 
         # Enables ReCaptcha checks when registering, preventing signup
         # unless a captcha is answered. Requires a valid ReCaptcha
         # public/private key.
         #
-        enable_registration_captcha: False
+        #enable_registration_captcha: false
 
         # A secret key used to bypass the captcha test entirely.
+        #
         #captcha_bypass_secret: "YOUR_SECRET_HERE"
 
         # The API endpoint to use for verifying m.login.recaptcha responses.
-        recaptcha_siteverify_api: "https://www.recaptcha.net/recaptcha/api/siteverify"
+        #
+        #recaptcha_siteverify_api: "https://www.recaptcha.net/recaptcha/api/siteverify"
         """