Logging the duration of each request will allow us to determine
whether there is a significant difference in the latency reported by
the comments service and that observed by the LMS. Each request will
be assigned a unique identifier to allow correlation of the reported
latency on each end.
Previously, authentication was done using a URL parameter, which would
appear in various logs. Now, authentication is done more appropriately
with an HTTP header. Note that this requires cs_comments_service commit
cf39aabdd160176ebf206ca19d3ee030161a0b47 or later.
According to someone from Datadog, this was generating tags like "knowledgeable_
people_who_put_this_course_together._this_is_harvard._you_can_t_tell_us_there_s_
a_shortage_of_editorial_talent." They say that they can handle tens or hundreds
of unique tags but not thousands. Given that we have a unique URL for each
thread, we can't even use that as a tag. Thus, all tags are removed for now
until we can determine whether there is a useful set of tags with small enough
cardinality. In light of this, I did not investigate why the long tag mentioned
above was being generated.
The LMS comment client previously would try to parse the response
as JSON, choke, and return a 500 to the client. Now, the LMS client
displays a message indicating that the forums are down for
maintenance.
