Commit Graph

2 Commits (4451a7c3643bc7375b26f6f00952131f5fb64446)

Author SHA1 Message Date
James Tucker 5c38f0979e tsweb/promvarz: fix repeated expvar definition in test
expvar can only be defined once, so running tests with a repeat counter
will fail if the variables are defined inside of the test function.

Observed failure:

```
--- FAIL: TestHandler (0.00s)
panic: Reuse of exported var name: gauge_promvarz_test_expvar
 [recovered]
        panic: Reuse of exported var name: gauge_promvarz_test_expvar

goroutine 9 [running]:
testing.tRunner.func1.2({0x100f267e0, 0x1400026e770})
        /usr/local/go/src/testing/testing.go:1526 +0x1c8
testing.tRunner.func1()
        /usr/local/go/src/testing/testing.go:1529 +0x364
panic({0x100f267e0, 0x1400026e770})
        /usr/local/go/src/runtime/panic.go:884 +0x1f4
log.Panicln({0x140000b8e20?, 0x1a?, 0x1400026e750?})
        /usr/local/go/src/log/log.go:398 +0x60
expvar.Publish({0x100e2b21d, 0x1a}, {0x100fd7a08?, 0x140000232c0})
        /usr/local/go/src/expvar/expvar.go:284 +0xc0
expvar.NewInt(...)
        /usr/local/go/src/expvar/expvar.go:304
tailscale.com/tsweb/promvarz.TestHandler(0x14000082b60)
        /Users/charlotte/ts-src/tailscale/tsweb/promvarz/promvarz_test.go:18 +0x5c
testing.tRunner(0x14000082b60, 0x100fd5858)
        /usr/local/go/src/testing/testing.go:1576 +0x104
created by testing.(*T).Run
        /usr/local/go/src/testing/testing.go:1629 +0x370
FAIL    tailscale.com/tsweb/promvarz    0.149s
```

Fixes #8065
Signed-off-by: James Tucker <james@tailscale.com>
2 years ago
Anton Tolchanov 8546ff98fb tsweb: move varz handler(s) into separate modules
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>
2 years ago