feat: adding ability to omit attributes for traces and metrics

[alocay]

Adding ability to configure which attributes are omitted from telemetry traces and metrics.

1. Using a Rust build script (build.rs) to auto-generate telemetry attribute code based on the data found in telemetry.toml.
2. Utilizing an enum for attributes so typos in the config file raise an error.
3. Omitting trace attributes by filtering it out in a custom exporter.
4. Omitting metric attributes by indicating which attributes are allowed via a view.
5. Created telemetry_attributes.rs to map TelemetryAttribute enum to a OTEL Key.

The telemetry.toml file includes attributes (both for metrics and traces) as well as list of metrics gathered. An example would look like the following:

[attributes.apollo.mcp]
my_attribute = "Some attribute info"

[metrics.apollo.mcp]
some.count = "Some metric count info"

This would generate a file that looks like the following:

/// All TelemetryAttribute values
pub const ALL_ATTRS: &[TelemetryAttribute; 1usize] = &[
    TelemetryAttribute::MyAttribute
];
#[derive(Debug, ::serde::Deserialize, ::schemars::JsonSchema,, Clone, Eq, PartialEq, Hash, Copy)]
pub enum TelemetryAttribute {
    ///Some attribute info
    #[serde(alias = "my_attribute")]
    MyAttribute,
}
impl TelemetryAttribute {
    /// Supported telemetry attribute (tags) values
    pub const fn as_str(&self) -> &'static str {
        match self {
            TelemetryAttribute::MyAttribute => "apollo.mcp.my_attribute",
        }
    }
}
#[derive(Debug, ::serde::Deserialize, ::schemars::JsonSchema,, Clone, Eq, PartialEq, Hash, Copy)]
pub enum TelemetryMetric {
    ///Some metric count info
    #[serde(alias = "some.count")]
    SomeCount,
}
impl TelemetryMetric {
    /// Converts TelemetryMetric to &str
    pub const fn as_str(&self) -> &'static str {
        match self {
            TelemetryMetric::SomeCount => "apollo.mcp.some.count",
        }
    }
}

An example configuration that omits tool_name attribute for metrics and request_id for tracing would look like the following:

telemetry:
  exporters:
    metrics:
      otlp:
        endpoint: "http://localhost:4317"
        protocol: "grpc"
      omitted_attributes:
        - tool_name
    tracing:
      otlp:
        endpoint: "http://localhost:4317"
        protocol: "grpc"
      omitted_attributes:
        - request_id

[apollo-librarian]

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* (developer-tools)/apollo-mcp-server/(latest)/index.mdx
* (developer-tools)/apollo-mcp-server/(latest)/limitations.mdx

Build ID: dcc498b7fd512a9837b8c86f
Build Logs: View logs

URL: https://www.apollographql.com/docs/deploy-preview/dcc498b7fd512a9837b8c86f

[alocay]

Unfortunately I have not figured out a way to use the const variables from the generated code in this fields() section.

[swcollard]

Is this test missing an assert? Or does not throwing an error show that it's working?

[alocay]

The assert is within the innner set_resource call which has:

assert!(true);

It's not an amazing test but since set_resource doesn't return anything I just assert within the set_resource function and call it day. Although this isn't great since calling nothing will also pass but I could not think of another way to ensure this. If any other inner function is called, it'll fail.