`#[instrument(fields(...))]` does not support dotted field names

[nikclayton-dfinity]

Bug Report

Version

tracing-attributes v0.1.8

Platform

Darwin Kernel Version 19.6.0: Mon Aug 31 22:12:52 PDT 2020; root:xnu-6153.141.2~1/RELEASE_X86_64 x86_64 i386 MacBookPro15,1 Darwin

Description

I want to set otel.kind in a function instrumented using #[instrument].

Reading the docs I figured

#[instrument(fields(otel.kind="server"))]

would do it, but that results in:

error: expected `,`
   --> redacted/mod.rs:168:41
    |
168 | #[instrument(fields(otel.kind="server"))]
                                   ^

You get the same error if otel.kind is quoted.

[nikclayton-dfinity]

I checked out the code to prepare a PR to fix this, and saw that the code does actually support this now. Looks like d24a43a#diff-9cbd60b122df9aadd01f63b729cf92e850d39bbb6ba8bb58c1d1d5c8be0e4e3c was the change that landed this.

With a Cargo.toml file that contains:

tracing = "0.1"

cargo fetched tracing-attributes 0.1.8, which is the version immediately before this support landed. I had to explicitly add tracing-attributes like so:

tracing = "0.1"
tracing-attributes = "0.1"

before cargo would update to the latest version (0.1.11 at time of writing).

The documentation is still out of date -- https://github.com/tokio-rs/tracing/blob/master/tracing-attributes/src/lib.rs#L117-L118 notes that dotted identifiers are not supported, and should be updated.

[hawkw]

With a Cargo.toml file that contains:

tracing = "0.1"

cargo fetched tracing-attributes 0.1.8, which is the version immediately before this support landed. I had to explicitly add tracing-attributes like so:

tracing = "0.1"
tracing-attributes = "0.1"

before cargo would update to the latest version (0.1.11 at time of writing).

Seems like a good fix would be to just bump the minimum version for tracing's tracing-attributes dependency, then --- I can do that right away!

[hawkw]

tracing v0.1.23 updates the minimum dependency on tracing-attributes to v0.1.12, and that release of tracing-attributes updates the docs to no longer claim that dotted field names are no longer supported --- which should fix this. Thanks for the report!