feat: set OTEL resource attributes from the instance settings

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RbLzVfFDZ9pjBGHSzCSrNZ

backend/src/monitor.rs

@@ -732,6 +732,8 @@ struct OtelSetting {
     otel_exporter_otlp_protocol: Option<String>,
     #[serde(default, deserialize_with = "empty_as_none")]
     otel_exporter_otlp_compression: Option<String>,
+    #[serde(default, deserialize_with = "empty_as_none")]
+    otel_resource_attributes: Option<String>,
 }
 
 pub async fn load_otel(db: &DB) {
@@ -788,6 +790,15 @@ pub async fn load_otel(db: &DB) {
                         std::env::set_var("OTEL_EXPORTER_OTLP_COMPRESSION", compression);
                     }
                 }
+                if let Some(resource_attributes) = o.otel_resource_attributes {
+                    let merged = windmill_common::tracing_init::merge_otel_resource_attributes(
+                        &resource_attributes,
+                        std::env::var("OTEL_RESOURCE_ATTRIBUTES").ok().as_deref(),
+                    );
+                    unsafe {
+                        std::env::set_var("OTEL_RESOURCE_ATTRIBUTES", merged);
+                    }
+                }
                 println!("OTEL settings loaded: tracing ({tracing_enabled}), logs ({logs_enabled}), metrics ({metrics_enabled}), endpoint ({:?}), headers defined: ({})",
                 endpoint, headers.is_some());
             } else {

backend/tests/otel.rs

@@ -745,3 +745,22 @@ fn test_otlp_resource_dedicated_overrides_win() {
         Some(windmill_common::utils::GIT_VERSION)
     );
 }
+
+#[test]
+#[serial_test::serial]
+fn test_otlp_resource_setting_attributes_keep_pod_attributes() {
+    let merged = windmill_common::tracing_init::merge_otel_resource_attributes(
+        "team=platform,region=eu-west-1",
+        Some("k8s.pod.uid=abc-123,region=us-east-1"),
+    );
+    std::env::set_var("OTEL_RESOURCE_ATTRIBUTES", merged);
+    let attrs = resource_attrs();
+    std::env::remove_var("OTEL_RESOURCE_ATTRIBUTES");
+
+    assert_eq!(
+        attrs.get("k8s.pod.uid").map(String::as_str),
+        Some("abc-123")
+    );
+    assert_eq!(attrs.get("team").map(String::as_str), Some("platform"));
+    assert_eq!(attrs.get("region").map(String::as_str), Some("us-east-1"));
+}

backend/windmill-common/src/instance_config.rs

@@ -631,6 +631,8 @@ pub struct OtelSettings {
     pub otel_exporter_otlp_protocol: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub otel_exporter_otlp_compression: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub otel_resource_attributes: Option<String>,
 }
 
 /// Per-language HTTP request tracing proxy configuration.

backend/windmill-common/src/tracing_init.rs

@@ -48,6 +48,17 @@ pub const VERBOSE_TARGET: &str = "windmill_verbose";
 /// when `OTEL_JOB_LOGS=true`. Stripped before forwarding to the tracing layer.
 pub const OTEL_PREFIX: &str = "OTEL: ";
 
+/// Combines the instance setting's resource attributes with the `OTEL_RESOURCE_ATTRIBUTES` the
+/// process started with, which a deployment sets per pod (e.g. `k8s.pod.uid` from the downward
+/// API). Overwriting it would drop those; the env's pairs go last because the SDK keeps the last
+/// value of a duplicate key, so the pod's own value wins.
+pub fn merge_otel_resource_attributes(from_setting: &str, from_env: Option<&str>) -> String {
+    match from_env.map(str::trim).filter(|v| !v.is_empty()) {
+        Some(from_env) => format!("{from_setting},{from_env}"),
+        None => from_setting.to_string(),
+    }
+}
+
 /// Creates a Targets filter that optionally filters out verbose logs when quiet mode is enabled.
 fn create_targets_filter(default_env_filter: LevelFilter) -> Targets {
     let targets =

frontend/src/lib/components/InstanceSetting.svelte

@@ -694,6 +694,26 @@
 									<option value="http/protobuf">http/protobuf</option>
 								</select>
 							</div>
+							<div class="flex flex-col gap-1">
+								<label
+									for="OTEL_RESOURCE_ATTRIBUTES"
+									class="block text-xs font-semibold text-emphasis">Resource attributes</label
+								>
+								<TextInput
+									inputProps={{
+										type: 'text',
+										placeholder: 'team=platform,region=eu-west-1',
+										id: 'OTEL_RESOURCE_ATTRIBUTES',
+										disabled: !$enterpriseLicense
+									}}
+									bind:value={$values[setting.key].otel_resource_attributes}
+								/>
+								<span class="text-2xs font-normal text-secondary">
+									Added to everything Windmill exports, alongside the OTEL_RESOURCE_ATTRIBUTES env
+									var, which wins on a shared key. Windmill's own service.name, service.version,
+									host.name and deployment.environment take precedence over both.
+								</span>
+							</div>
 						{/if}
 					</div>
 				{:else if setting.fieldType == 'otel_tracing_proxy'}