The tsweb DebugHandler already links to expvar, Prometheus varz, and
pprof, but the only runtime visibility beyond pprof was the handful of
runtime.MemStats fields that varz special-cases. The runtime/metrics
package has far more (GC CPU classes, scheduler latencies, stop-the-world
pause histograms, heap breakdowns, and so on) and is the runtime's
preferred, cheaper interface.
Add a /debug/runtime-metrics handler. By default it serves only an index
of metric names, kinds, and descriptions, which are static, so viewing
the page does not read any values. The index is an HTML table for
browsers (Accept: text/html) and plain text otherwise; format=html or
format=text overrides the sniffing.
Values are read only on request, always as JSON:
- /debug/runtime-metrics/gc/heap/allocs:bytes returns that metric's
bare value, handy for scripts and curl.
- /debug/runtime-metrics?name=NAME (repeatable) returns a JSON object
keyed by metric name. A trailing * matches by prefix, so name=/gc/*
returns the GC metrics and name=* returns everything.
Histograms are objects with counts and buckets arrays; infinite bucket
boundaries, which JSON cannot represent, are the strings "-Inf" and
"+Inf".
In the HTML index, exact metric names link to the bare value form, and
each run of metrics sharing a directory is headed by a row linking every
ancestor directory to its wildcard query (/gc/*, /gc/heap/*, ...).
Responses inherit the debug handler's nosniff, framing, and CSP headers,
and application/json is not a script MIME type, so the values cannot be
pulled in cross-origin as a script by a malicious page.
Like the pprof handlers, this is excluded from js/wasm builds to keep
them small.
Updates #21300
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I7c2e9f4a1b8d3e6f0a5c9b2d4e7f1a3c6b8d0e2f
This file was never truly necessary and has never actually been used in
the history of Tailscale's open source releases.
A Brief History of AUTHORS files
---
The AUTHORS file was a pattern developed at Google, originally for
Chromium, then adopted by Go and a bunch of other projects. The problem
was that Chromium originally had a copyright line only recognizing
Google as the copyright holder. Because Google (and most open source
projects) do not require copyright assignemnt for contributions, each
contributor maintains their copyright. Some large corporate contributors
then tried to add their own name to the copyright line in the LICENSE
file or in file headers. This quickly becomes unwieldy, and puts a
tremendous burden on anyone building on top of Chromium, since the
license requires that they keep all copyright lines intact.
The compromise was to create an AUTHORS file that would list all of the
copyright holders. The LICENSE file and source file headers would then
include that list by reference, listing the copyright holder as "The
Chromium Authors".
This also become cumbersome to simply keep the file up to date with a
high rate of new contributors. Plus it's not always obvious who the
copyright holder is. Sometimes it is the individual making the
contribution, but many times it may be their employer. There is no way
for the proejct maintainer to know.
Eventually, Google changed their policy to no longer recommend trying to
keep the AUTHORS file up to date proactively, and instead to only add to
it when requested: https://opensource.google/docs/releasing/authors.
They are also clear that:
> Adding contributors to the AUTHORS file is entirely within the
> project's discretion and has no implications for copyright ownership.
It was primarily added to appease a small number of large contributors
that insisted that they be recognized as copyright holders (which was
entirely their right to do). But it's not truly necessary, and not even
the most accurate way of identifying contributors and/or copyright
holders.
In practice, we've never added anyone to our AUTHORS file. It only lists
Tailscale, so it's not really serving any purpose. It also causes
confusion because Tailscalars put the "Tailscale Inc & AUTHORS" header
in other open source repos which don't actually have an AUTHORS file, so
it's ambiguous what that means.
Instead, we just acknowledge that the contributors to Tailscale (whoever
they are) are copyright holders for their individual contributions. We
also have the benefit of using the DCO (developercertificate.org) which
provides some additional certification of their right to make the
contribution.
The source file changes were purely mechanical with:
git ls-files | xargs sed -i -e 's/\(Tailscale Inc &\) AUTHORS/\1 contributors/g'
Updates #cleanup
Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>
Allows the use of tsweb without pulling in all of the heavy prometheus
client libraries, protobuf and so on.
Updates #15160
Signed-off-by: David Anderson <dave@tailscale.com>
Allow customizing the title on the debug index page. Also add methods
for registering http.HandlerFunc to make it a little easier on callers.
Updates tailscale/corp#27058
Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>
* tsweb: update ServeMux matching to 1.22.0 syntax
Updates #cleanup
Go 1.22.0 introduced the ability to use more expressive routing patterns
that include HTTP method when constructing ServeMux entries.
Applications that attempted to use these patterns in combination with
the old `tsweb.Debugger` would experience a panic as Go would not permit
the use of matching rules with mixed level of specificity. We now
specify the method for each `/debug` handler to prevent
incompatibilities.
Signed-off-by: Patrick O'Doherty <patrick@tailscale.com>
This reverts commit 291f91d164.
Updates #cleanup
This PR needs additional changes to the registration of child handlers under /debug
Signed-off-by: Patrick O'Doherty <patrick@tailscale.com>
Updates #cleanup
Go 1.22.0 introduced the ability to use more expressive routing patterns
that include HTTP method when constructing ServeMux entries.
Applications that attempted to use these patterns in combination with
the old `tsweb.Debugger` would experience a panic as Go would not permit
the use of matching rules with mixed level of specificity.
Signed-off-by: Patrick O'Doherty <patrick@tailscale.com>
plugin-types is deprecated, and setting object-src: 'none' is best
practice. This should result in no functional change.
Fixes#10718
Signed-off-by: Chris Palmer <cpalmer@tailscale.com>
Allow inline CSS for debug handlers to make prototyping easier. These
are generally not accessible to the public and the small risk of CSS
injection via user content seems acceptable.
Also allow form submissions on the same domain, instead of banning all
forms. An example of such form is
http://webhooks.corp.ts.net:6359/debug/private-nodes/
Updates #3576
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
Add a few helper functions in tsweb to add common security headers to handlers. Use those functions for all non-tailscaled-facing endpoints in derper.
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
This splits Prometheus metric handlers exposed by tsweb into two
modules:
- `varz.Handler` exposes Prometheus metrics generated by our expvar
converter;
- `promvarz.Handler` combines our expvar-converted metrics and native
Prometheus metrics.
By default, tsweb will use the promvarz handler, however users can keep
using only the expvar converter. Specifically, `tailscaled` now uses
`varz.Handler` explicitly, which avoids a dependency on the
(heavyweight) Prometheus client.
Updates https://github.com/tailscale/corp/issues/10205
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
This updates all source files to use a new standard header for copyright
and license declaration. Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.
This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.
Updates #6865
Signed-off-by: Will Norris <will@tailscale.com>
Brad Fitzpatrick