add ingestion mechanism documentation for rust

content/en/tracing/trace_pipeline/ingestion_mechanisms.md

@@ -282,6 +282,23 @@
 [1]: https://github.com/DataDog/dd-trace-cpp/releases/tag/v0.1.0
 [2]: /tracing/trace_collection/proxy_setup
 {{% /tab %}}
+{{% tab "Rust" %}}
+**Local configuration**
+
+For Rust applications, set by-service sampling rates with the `DD_TRACE_SAMPLING_RULES` environment variable.
+
+For example, to send 50% of the traces for the service named `my-service` and 10% for the rest of the traces:
+
+```
+export DD_TRACE_SAMPLING_RULES='[{"service": "my-service", "sample_rate": 0.5},{"sample_rate": 0.1}]'
+```
+
+Configure a rate limit by setting the `DD_TRACE_RATE_LIMIT` environment variable to the maximum traces per second per service instance. If no `DD_TRACE_RATE_LIMIT` value is set, a limit of 100 traces per second is applied.
+
+Read more about sampling controls in the [Rust SDK documentation][1].
+
+[1]: /tracing/trace_collection/dd_libraries/rust
+{{% /tab %}}
 {{% tab ".NET" %}}
 For .NET applications, set a global sampling rate for the library using the `DD_TRACE_SAMPLE_RATE` environment variable. Set by-service sampling rates with the `DD_TRACE_SAMPLING_RULES` environment variable.
 
@@ -400,7 +417,7 @@
 
 - Set Manual Drop on a span to make sure that **no** child span is ingested. The [error and rare samplers](#error-and-rare-traces) are ignored in the Agent.
 
-{{< programming-lang-wrapper langs="java,python,ruby,go,nodejs,.NET,php,cpp" >}}
+{{< programming-lang-wrapper langs="java,python,ruby,go,nodejs,.NET,php,cpp,rust" >}}
 {{< programming-lang lang="java" >}}
 
 Manually keep a trace:
@@ -685,6 +702,11 @@
 //method impl follows
 ```
 
+{{< /programming-lang >}}
+{{< programming-lang lang="rust" >}}
+
+<div class="alert alert-info">The Rust SDK uses the OpenTelemetry API and does not support the Datadog <code>ManualKeep</code>/<code>ManualDrop</code> tags. To force keep or drop a trace in Rust, set the OpenTelemetry <code>sampling.priority</code> attribute on the root span using <a href="/tracing/trace_collection/custom_instrumentation/rust">custom instrumentation</a>.</div>
+
 {{< /programming-lang >}}
 {{< /programming-lang-wrapper >}}
 
@@ -805,6 +827,15 @@
 
 [1]: https://github.com/DataDog/dd-trace-cpp/releases/tag/v0.1.0
 {{% /tab %}}
+{{% tab "Rust" %}}
+For Rust applications, set by-service and by-operation name **span** sampling rules with the `DD_SPAN_SAMPLING_RULES` environment variable.
+
+For example, to collect `100%` of the spans from the service named `my-service`, for the operation `http.request`, up to `50` spans per second:
+
+```
+@env DD_SPAN_SAMPLING_RULES=[{"service": "my-service", "name": "http.request", "sample_rate":1.0, "max_per_second": 50}]
+```
+{{% /tab %}}
 {{% tab ".NET" %}}
 Starting from version [v2.18.0][1], for .NET applications, set by-service and by-operation name **span** sampling rules with the `DD_SPAN_SAMPLING_RULES` environment variable.