Feat: For the AWS EMF and XRay exporters, changing their respective '…

README.md

@@ -254,7 +254,7 @@ X-Ray exporter.
 
 | Option                             | Default   | Options          |
 |------------------------------------|-----------|------------------|
-| --awsxray-exporter-region          | us-east-1 | aws region codes |
+| --awsxray-exporter-region | `AWS_REGION` env-var if set, then `AWS_DEFAULT_REGION`, then `us-east-1` | aws region codes |
 | --awsxray-exporter-custom-endpoint |           |                  |
 
 For a list of available AWS X-Ray region codes here: https://docs.aws.amazon.com/general/latest/gr/xray.html
@@ -272,7 +272,7 @@ exporter.
 
 | Option                                                 | Default          | Options          |
 |--------------------------------------------------------|------------------|------------------|
-| --awsemf-exporter-region                               | us-east-1        | aws region codes |
+| --awsemf-exporter-region | `AWS_REGION` env-var if set, then `AWS_DEFAULT_REGION`, then `us-east-1` | aws region codes |
 | --awsemf-exporter-custom-endpoint                      |                  |                  |
 | --awsemf-exporter-log-group-name                       | /metrics/default |                  |
 | --awsemf-exporter-log-stream-name                      | otel-stream      |                  |

src/exporters/shared/aws.rs

@@ -79,9 +79,11 @@ impl Display for Region {
     }
 }
 
-impl From<String> for Region {
-    fn from(s: String) -> Self {
-        match s.as_str() {
+impl core::str::FromStr for Region {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
             "us-east-1" => Region::UsEast1,
             "us-east-2" => Region::UsEast2,
             "us-west-1" => Region::UsWest1,
@@ -114,7 +116,31 @@ impl From<String> for Region {
             "me-south-1" => Region::MeSouth1,
             "me-central-1" => Region::MeCentral1,
             "sa-east-1" => Region::SaEast1,
-            _ => panic!("Unknown region: {}", s),
-        }
+            _ => return Err(format!("Unknown region: {}", s)),
+        })
+    }
+}
+
+impl From<String> for Region {
+    fn from(s: String) -> Self {
+        s.parse().unwrap()
+    }
+}
+
+impl Default for Region {
+    fn default() -> Self {
+        use std::env;
+        // Try to read AWS_REGION
+        env::var("AWS_REGION")
+            // Else, try to read AWS_DEFAULT_REGION
+            .or_else(|_| env::var("AWS_DEFAULT_REGION"))
+            // Discard the error
+            .ok()
+            // Parse the value and discard the error
+            .map(|s| s.parse().ok())
+            // Flatten the result
+            .flatten()
+            // Unwrap it or fallback on us-east-1
+            .unwrap_or_else(|| Region::UsEast1)
     }
 }

src/exporters/xray/mod.rs

@@ -70,7 +70,7 @@ pub struct XRayExporterConfigBuilder {
 impl Default for XRayExporterConfigBuilder {
     fn default() -> Self {
         Self {
-            region: Region::UsEast1,
+            region: Default::default(),
             custom_endpoint: None,
             retry_config: Default::default(),
         }

src/init/awsemf_exporter.rs

@@ -9,10 +9,9 @@ pub struct AwsEmfExporterArgs {
     /// AWS EMF Exporter Region
     #[arg(
         id("AWSEMF_REGION"),
-        value_enum,
         long("awsemf-exporter-region"),
         env = "ROTEL_AWSEMF_EXPORTER_REGION",
-        default_value = "us-east-1"
+        default_value_t
     )]
     pub region: Region,
 
@@ -82,7 +81,7 @@ pub struct AwsEmfExporterArgs {
 impl Default for AwsEmfExporterArgs {
     fn default() -> Self {
         Self {
-            region: Region::UsEast1,
+            region: Region::default(),
             custom_endpoint: None,
             log_group_name: "/metrics/default".to_string(),
             log_stream_name: "otel-stream".to_string(),

src/init/xray_exporter.rs

@@ -3,15 +3,14 @@ use serde::Deserialize;
 
 use crate::exporters::shared::aws::Region;
 
-#[derive(Debug, Clone, Args, Deserialize)]
+#[derive(Debug, Default, Clone, Args, Deserialize)]
 #[serde(default)]
 pub struct XRayExporterArgs {
     /// AWS X-Ray Exporter Region
     #[arg(
-        value_enum,
         long("awsxray-exporter-region"),
         env = "ROTEL_AWSXRAY_EXPORTER_REGION",
-        default_value = "us-east-1"
+        default_value_t
     )]
     pub region: Region,
 
@@ -22,12 +21,3 @@ pub struct XRayExporterArgs {
     )]
     pub custom_endpoint: Option<String>,
 }
-
-impl Default for XRayExporterArgs {
-    fn default() -> Self {
-        Self {
-            region: Region::UsEast1,
-            custom_endpoint: None,
-        }
-    }
-}