enhancement(gcp_chronicle sink): Add default fallback logic if log_ty…

…pe template cannot be resolved fo… (#22323)

* add default fallback logic if log_type template cannot be resolved for Google Chronicle sink

* modify error message

* fix changelog

* format

* update docs

* add suggested changes

* update docs again

changelog.d/add_default_fallback_index_google_chronicle_sink.enhancement.md

@@ -0,0 +1,3 @@
+Add an option to Google Chronicle sink to set a fallback index if the provided template in the `log_type` field cannot be resolved
+
+authors: ArunPiduguDD

src/sinks/gcp_chronicle/chronicle_unstructured.rs

@@ -237,6 +237,10 @@ pub struct ChronicleUnstructuredConfig {
     #[configurable(metadata(docs::examples = "WINDOWS_DNS", docs::examples = "{{ log_type }}"))]
     pub log_type: Template,
 
+    /// The default `log_type` to attach to events if the template in `log_type` cannot be resolved.
+    #[configurable(metadata(docs::examples = "VECTOR_DEV"))]
+    pub fallback_log_type: Option<String>,
+
     #[configurable(derived)]
     #[serde(
         default,
@@ -261,6 +265,7 @@ impl GenerateConfig for ChronicleUnstructuredConfig {
             namespace = "namespace"
             compression = "gzip"
             log_type = "log_type"
+            fallback_log_type = "VECTOR_DEV"
             encoding.codec = "text"
         "#})
         .unwrap()
@@ -355,6 +360,7 @@ impl ChronicleUnstructuredConfig {
     fn partitioner(&self) -> crate::Result<ChroniclePartitioner> {
         Ok(ChroniclePartitioner::new(
             self.log_type.clone(),
+            self.fallback_log_type.clone(),
             self.namespace.clone(),
         ))
     }

src/sinks/gcp_chronicle/partitioner.rs

@@ -9,11 +9,23 @@ pub struct ChroniclePartitionKey {
 }
 
 /// Partitions items based on the generated key for the given event.
-pub struct ChroniclePartitioner(Template, Option<Template>);
+pub struct ChroniclePartitioner {
+    log_type: Template,
+    fallback_log_type: Option<String>,
+    namespace_template: Option<Template>,
+}
 
 impl ChroniclePartitioner {
-    pub const fn new(log_type_template: Template, namespace_template: Option<Template>) -> Self {
-        Self(log_type_template, namespace_template)
+    pub const fn new(
+        log_type: Template,
+        fallback_log_type: Option<String>,
+        namespace_template: Option<Template>,
+    ) -> Self {
+        Self {
+            log_type,
+            fallback_log_type,
+            namespace_template,
+        }
     }
 }
 
@@ -23,18 +35,28 @@ impl Partitioner for ChroniclePartitioner {
 
     fn partition(&self, item: &Self::Item) -> Self::Key {
         let log_type = self
-            .0
+            .log_type
             .render_string(item)
-            .map_err(|error| {
-                emit!(TemplateRenderingError {
-                    error,
-                    field: Some("log_type"),
-                    drop_event: true,
-                });
+            .or_else(|error| {
+                if let Some(fallback_log_type) = &self.fallback_log_type {
+                    emit!(TemplateRenderingError {
+                        error,
+                        field: Some("log_type"),
+                        drop_event: false,
+                    });
+                    Ok(fallback_log_type.clone())
+                } else {
+                    Err(emit!(TemplateRenderingError {
+                        error,
+                        field: Some("log_type"),
+                        drop_event: true,
+                    }))
+                }
             })
             .ok()?;
+
         let namespace = self
-            .1
+            .namespace_template
             .as_ref()
             .map(|namespace| {
                 namespace.render_string(item).map_err(|error| {

website/cue/reference/components/sinks/base/gcp_chronicle_unstructured.cue

@@ -464,6 +464,11 @@ base: components: sinks: gcp_chronicle_unstructured: configuration: {
 		required:    false
 		type: string: examples: ["127.0.0.1:8080", "example.com:12345"]
 	}
+	fallback_log_type: {
+		description: "The default `log_type` to attach to events if the template in `log_type` cannot be resolved."
+		required:    false
+		type: string: examples: ["VECTOR_DEV"]
+	}
 	labels: {
 		description: "A set of labels that are attached to each batch of events."
 		required:    false