I agree with Johnny that an enterprise policy would be useful, at least
for a few milestones.
On 1/30/23 5:16 AM, 'Harald Alvestrand' via blink-dev wrote:
I'm not sure an enterprise policy is appropriate - I see the same
problem with sunsetting the policy as with sunsetting the stat in
general, and usage of enterprise policies is (as far as I know) far
more opaque to us than origin trials or Finch feature usage.
On Mon, Jan 30, 2023 at 11:13 AM Henrik Boström <h...@chromium.org> wrote:
On Friday, January 27, 2023 at 7:24:58 PM UTC+1 Johnny Stenback wrote:
Is there an enterprise policy in place for this deprecation
already? If not, adding one seems appropriate given the challenges
of rolling out even simple fixes in some enterprise environments.
One does not exist at the moment but I can add one
<https://chromium.googlesource.com/chromium/src/+/HEAD/docs/enterprise/add_new_policy.md>.
Thanks,
Johnny
On Fri, Jan 27, 2023 at 5:16 AM Henrik Boström <h...@chromium.org>
wrote:
Delaying the enabled-by-default to M112 is fine by me but I'll
wait for a resolution here before taking action. Currently it is
enabled-by-default in Canary.
On Friday, January 27, 2023 at 12:41:23 PM UTC+1
philipp...@googlemail.com wrote:
Am Fr., 27. Jan. 2023 um 11:49 Uhr schrieb Henrik Boström
<h...@chromium.org>:
*Contact emails*
h...@chromium.org, h...@chromium.org
*Background*
I attempted to remove this feature before but had forgotten to
file an intent to deprecate, background here
<https://groups.google.com/a/chromium.org/g/blink-dev/c/RsIktnGhHqw/>.
*
*
*Specification*
The getStats() API spec is here
<https://w3c.github.io/webrtc-stats/> and it contains all the
metrics. The deprecated metrics are also listed, but in the
obsolete section
<https://w3c.github.io/webrtc-stats/#obsolete-rtcmediastreamtrackstats-members>.
There's an open issue to remove obsolete metrics from the spec as
soon as they are unshipped from modern browsers. This is
considered a blocker for the document to reach Proposed
Recommendation status.
*
*
*Summary*
WebRTC is a set of JavaScript APIs (spec
<https://w3c.github.io/webrtc-pc/>) that allow real-time
communication between browsers. For the relevant metrics being
removed, we're only talking about the WebRTC use case that is
sending or receiving audio or video (typically Video Conferencing
use cases), not the data channel use cases that is a popular
WebRTC use case, since data channel only use cases would never
have any tracks/streams.
*
*
RTCPeerConnection.getStats() returns a map of string-to-objects,
where each object is one of the dictionaries defined in the stats
spec. The reason an app calls getStats() is mostly to report
quality metrics (send and receive resolutions, bitrates, glitches,
video QP, etc) which can be important for A/B experimentation. It
can also be used in a way that impacts app logic or even UX inside
the app. Most common use case I can think of: poll getStats() at
10 Hz and render volume bars for each participant based on volume
levels from stats objects.
The deprecation in question is to remove some stats objects that
were made obsolete several years ago: all metrics on the "track"
dictionary have been moved to non-obsolete objects ("inbound-rtp",
"outbound-rtp", "media-source"). Reasons for wanting to deprecate
include:
* Spec-compliance: needed for browser implementations to align
and for the spec to become Proposed Recommendation.
* Web compat: Firefox never implement "track" or "steam"
<https://wpt.fyi/results/webrtc-stats/supported-stats.https.html?label=experimental&label=master&aligned>
due
to them being obsolete.
* Performance: the duplicated metrics make up ~40% of the stats
report size, which can be a significant number of bytes in
larger meetings and it is common for apps to poll getStats()
10 times per second.
* Tech debt: unblock removal of 1400 LOC.
In the meantime, the obsolete metrics is duplicated in several
places of the stats report.
*
*
*Risks*
*- Impossible to properly measure usage*
Because stats objects are exposed as JavaScript dictionaries, and
because apps have to iterate all objects of the stats report in
order to find the ones they are interested in or if they just dump
all the data without filtering, there is no way to measure how big
the dependency is on track in the real world.
*
*
While we lack use counters, we have some positive signs:
* Because Firefox does not have "track" or "stream" stats, any
app that can run on Firefox already exercises the paths of
these not existing.
* An experiment to "unship deprecated metrics" has been running
at 50% Canary since October
<https://groups.google.com/a/chromium.org/g/blink-dev/c/RsIktnGhHqw/m/3iqjODsMBwAJ>,
giving developers testing Canary a heads-up. Nobody complained
until the experiment reached Stable.
* We got to 50% Stable in M109 and while we're in the process of
rolling it back now due to breaking twilio-video.js
<https://github.com/twilio/twilio-video.js/issues/1968>, it's
interesting to note that this is the only breakage we are
aware of (that does not mean there aren't more breakages, but
I believe this at least says something about the severity).
*- Selenium et al typically starts browsers from fresh profiles
and hence does not know the finch trial seed*
The most likely explanation for breakage is not testing Canary or
test environments not having access to Finch experiments. This
makes the behavior on Stable a surprise.
*- To have a Reverse Origin Trial or not to have a Reverse Origin
Trial?*
Migrating should require so few lines of code (look for stats.type
== 'inbound-rtp' instead of stats.type == 'track', for example)
that it seems to be a bigger hurdle for a developer to enroll in
the trial than to simply fix their code.
*
*
*- Compatiblity risk*
There is one particular metric out of all metrics that, if you run
Safari, does not exist on "inbound-rtp" yet. This can be a
problem, but again is probably not a big problem because this
particular metric was never implemented on Firefox so apps already
need to survive without it, and it is very easy to write a
fallback path for the Safari case:
let trackIdentifer = null; // In Firefox this will never be set
regardless.
if (inboundRtp.trackIdentifier) {
// Spec-compliant browser.
trackIdentifier = inboundRtp.trackIdentifier;
} else if (inboundRtp.trackId) {
// Fallback-path for Safari or 1+ year old Chromium browsers.
trackIdentifier = report.get(inboundRtp.trackId).trackIdentifier;
}
*
*
*Proposal*
Rollback to 0% Stable but keep the "unship deprecated" experiment
at 50% Canary/Beta. Wait for Twilio to fix their issue and do
another rollout attempt. Keep a slower rollout pace next time.
I see limited amount of value in a Reverse Origin Trial since it
appears to be more effort to register to the trial than to fix the
issue, if you are affected.
I do prefer to have the feature enabled-by-default in M111+ and
overwrite that default via Finch rather than the other way around
as to not "turn off the fire alarm" for non-Finch testing
environments. I realize that is not perfect (what if you run in a
non-Finch environment) but it would reduce overall risk.
Thank you Henrik. I agree with one suggestion: only do default-off
in M112+ (which is branching so you would just need to revert this
commit
<https://chromiumdash.appspot.com/commit/3a4d52f365df03413a856ea20366b36e8fb8ea0b>
on
the M111 branch).
This gives developers another month to update (which itself should
be quick) and then rolling it out to their customers and users
(which takes time).
I hope that the 50% rollout caused enough incidents (even though
you may never hear about some of them) to get the fixes in ASAP.
cheers
Philipp
--
You received this message because you are subscribed to the Google
Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to blink-dev+unsubscr...@chromium.org
<mailto:blink-dev+unsubscr...@chromium.org>.
To view this discussion on the web visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/5ecf1ea6-c16c-464a-b529-439e05e4feedn%40chromium.org
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/5ecf1ea6-c16c-464a-b529-439e05e4feedn%40chromium.org?utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google
Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to blink-dev+unsubscr...@chromium.org
<mailto:blink-dev+unsubscr...@chromium.org>.
To view this discussion on the web visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a0b5bb9-addd-4a56-b053-1429bbaabe2dn%40chromium.org
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a0b5bb9-addd-4a56-b053-1429bbaabe2dn%40chromium.org?utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google
Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to blink-dev+unsubscr...@chromium.org.
To view this discussion on the web visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOqqYVG_P0ji6Z-n0DoCua4nzJZN7S48o23%3DUpx_ELerqphfUg%40mail.gmail.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOqqYVG_P0ji6Z-n0DoCua4nzJZN7S48o23%3DUpx_ELerqphfUg%40mail.gmail.com?utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google Groups
"blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to blink-dev+unsubscr...@chromium.org.
To view this discussion on the web visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/8bab6e75-28ad-2f8b-02f8-4a797c68c21e%40chromium.org.
