Refactor ads-client to integrate context_id component (#6958)

Author: Almaju

CHANGELOG.md

@@ -4,9 +4,11 @@
 
 ### Swift
 - Added `@unchecked Sendable` to classes that conform to `FeatureManifestInterface`. ([#6963](https://github.com/mozilla/application-services/pull/6963)
+
 ### Ads Client
 - Added the Ads Client component to the Megazord.
 - Updated the ApiError enum to AdsClientApiError to avoid naming collision.
+- The `context_id` is now generated and rotated via the existing eponym component crate.
 
 # v144.0 (_2025-09-15_)
 

Cargo.lock

@@ -5,19 +5,20 @@ edition = "2021"
 license = "MPL-2.0"
 
 [dependencies]
+context_id = { path = "../context_id" }
+error-support = { path = "../support/error" }
 parking_lot = "0.12"
 serde = "1"
 serde_json = "1"
-url = "2"
+thiserror = "2"
 uniffi = { version = "0.29.0" }
+url = "2"
 uuid = { version = "1.3", features = ["v4"] }
 viaduct = { path = "../viaduct" }
-error-support = { path = "../support/error" }
-thiserror = "2"
 
 [dev-dependencies]
-mockito = { version = "0.31", default-features = false}
 mockall = "0.12"
+mockito = { version = "0.31", default-features = false }
 viaduct-dev = { path = "../support/viaduct-dev" }
 
 [build-dependencies]

components/ads-client/Cargo.toml

@@ -14,6 +14,14 @@ pub enum AdsClientApiError {
     Other { reason: String },
 }
 
+impl From<context_id::ApiError> for AdsClientApiError {
+    fn from(err: context_id::ApiError) -> Self {
+        AdsClientApiError::Other {
+            reason: err.to_string(),
+        }
+    }
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum ComponentError {
     #[error("Error requesting ads: {0}")]
@@ -53,6 +61,9 @@ pub enum RequestAdsError {
 
 #[derive(Debug, thiserror::Error)]
 pub enum BuildRequestError {
+    #[error(transparent)]
+    ContextId(#[from] context_id::ApiError),
+
     #[error("Could not build request with empty placement configs")]
     EmptyConfig,
 

components/ads-client/src/error.rs

@@ -88,7 +88,7 @@ impl MozAdsClient {
 
     pub fn cycle_context_id(&self) -> AdsClientApiResult<String> {
         let mut inner = self.inner.lock();
-        let previous_context_id = inner.cycle_context_id();
+        let previous_context_id = inner.cycle_context_id()?;
         Ok(previous_context_id)
     }
 
@@ -159,7 +159,7 @@ impl MozAdsClientInner {
         Ok(())
     }
 
-    fn cycle_context_id(&mut self) -> String {
+    fn cycle_context_id(&mut self) -> context_id::ApiResult<String> {
         self.client.cycle_context_id()
     }
 
@@ -171,7 +171,7 @@ impl MozAdsClientInner {
             return Err(BuildRequestError::EmptyConfig);
         }
 
-        let context_id = self.client.get_context_id().to_string();
+        let context_id = self.client.get_context_id()?;
         let mut request = AdRequest {
             placements: vec![],
             context_id,
@@ -288,7 +288,7 @@ mod tests {
     fn test_build_ad_request_happy() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -327,7 +327,7 @@ mod tests {
         let request = inner_component
             .build_request_from_placement_configs(&configs)
             .unwrap();
-        let context_id = inner_component.client.get_context_id().to_string();
+        let context_id = inner_component.client.get_context_id().unwrap();
 
         let expected_request = AdRequest {
             context_id,
@@ -366,7 +366,7 @@ mod tests {
     fn test_build_ad_request_fails_on_duplicate_placement_id() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -411,7 +411,7 @@ mod tests {
     fn test_build_ad_request_fails_on_empty_configs() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -428,7 +428,7 @@ mod tests {
     fn test_build_placements_happy() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -449,7 +449,7 @@ mod tests {
     fn test_build_placements_with_empty_placement_in_response() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -486,7 +486,7 @@ mod tests {
     fn test_request_ads_with_missing_callback_in_response() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -518,7 +518,7 @@ mod tests {
     fn test_build_placements_fails_with_duplicate_placement() {
         let mut mock = MockMARSClient::new();
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         let inner_component = MozAdsClientInner {
             ads_cache: HashMap::new(),
@@ -572,7 +572,7 @@ mod tests {
         mock.expect_fetch_ads()
             .returning(|_req| Ok(get_example_happy_ad_response()));
         mock.expect_get_context_id()
-            .return_const("mock-context-id".to_string());
+            .returning(|| Ok("mock-context-id".to_string()));
 
         mock.expect_get_mars_endpoint()
             .return_const("https://mock.endpoint/ads".to_string());

components/ads-client/src/lib.rs

@@ -10,8 +10,8 @@ use crate::{
     },
     models::{AdRequest, AdResponse},
 };
+use context_id::{ContextIDComponent, DefaultContextIdCallback};
 use url::Url;
-use uuid::Uuid;
 use viaduct::Request;
 
 const DEFAULT_MARS_API_ENDPOINT: &str = "https://ads.mozilla.org/v1";
@@ -25,28 +25,38 @@ pub trait MARSClient: Sync + Send {
     ) -> Result<(), RecordImpressionError>;
     fn record_click(&self, url_callback_string: Option<String>) -> Result<(), RecordClickError>;
     fn report_ad(&self, url_callback_string: Option<String>) -> Result<(), ReportAdError>;
-    fn get_context_id(&self) -> &str;
-    fn cycle_context_id(&mut self) -> String;
+    fn get_context_id(&self) -> context_id::ApiResult<String>;
+    fn cycle_context_id(&mut self) -> context_id::ApiResult<String>;
     fn get_mars_endpoint(&self) -> &str;
 }
 
 pub struct DefaultMARSClient {
-    context_id: String,
+    context_id_component: ContextIDComponent,
     endpoint: String,
 }
 
 impl DefaultMARSClient {
     pub fn new(context_id: String) -> Self {
         Self {
-            context_id,
+            context_id_component: ContextIDComponent::new(
+                &context_id,
+                0,
+                false,
+                Box::new(DefaultContextIdCallback),
+            ),
             endpoint: DEFAULT_MARS_API_ENDPOINT.to_string(),
         }
     }
 
     #[cfg(test)]
     pub fn new_with_endpoint(context_id: String, endpoint: String) -> Self {
         Self {
-            context_id,
+            context_id_component: ContextIDComponent::new(
+                &context_id,
+                0,
+                false,
+                Box::new(DefaultContextIdCallback),
+            ),
             endpoint,
         }
     }
@@ -60,20 +70,18 @@ impl DefaultMARSClient {
 }
 
 impl MARSClient for DefaultMARSClient {
-    fn get_context_id(&self) -> &str {
-        &self.context_id
+    fn cycle_context_id(&mut self) -> context_id::ApiResult<String> {
+        let old_context_id = self.get_context_id()?;
+        self.context_id_component.force_rotation()?;
+        Ok(old_context_id)
     }
 
-    fn get_mars_endpoint(&self) -> &str {
-        &self.endpoint
+    fn get_context_id(&self) -> context_id::ApiResult<String> {
+        self.context_id_component.request(0)
     }
 
-    /// Updates the client's context_id to the passed value and returns the previous context_id
-    /// TODO: Context_id functions should swap over to use the proper context_id component
-    fn cycle_context_id(&mut self) -> String {
-        let old_context_id = self.context_id.clone();
-        self.context_id = Uuid::new_v4().to_string();
-        old_context_id
+    fn get_mars_endpoint(&self) -> &str {
+        &self.endpoint
     }
 
     fn fetch_ads(&self, ad_request: &AdRequest) -> Result<AdResponse, FetchAdsError> {
@@ -136,15 +144,18 @@ mod tests {
     #[test]
     fn test_get_context_id() {
         let client = create_test_client(mockito::server_url());
-        assert_eq!(client.get_context_id(), TEST_CONTEXT_ID.to_string());
+        assert_eq!(
+            client.get_context_id().unwrap(),
+            TEST_CONTEXT_ID.to_string()
+        );
     }
 
     #[test]
     fn test_cycle_context_id() {
         let mut client = create_test_client(mockito::server_url());
-        let old_id = client.cycle_context_id();
+        let old_id = client.cycle_context_id().unwrap();
         assert_eq!(old_id, TEST_CONTEXT_ID);
-        assert_ne!(client.get_context_id(), TEST_CONTEXT_ID);
+        assert_ne!(client.get_context_id().unwrap(), TEST_CONTEXT_ID);
     }
 
     #[test]
@@ -219,7 +230,7 @@ mod tests {
         let client = create_test_client(mockito::server_url());
 
         let ad_request = AdRequest {
-            context_id: client.get_context_id().to_string(),
+            context_id: client.get_context_id().unwrap().to_string(),
             placements: vec![
                 AdPlacementRequest {
                     placement: "example_placement_1".to_string(),

components/ads-client/src/mars.rs

@@ -11,7 +11,7 @@ use crate::{
     IABContent, MozAdsPlacement, MozAdsPlacementConfig,
 };
 
-pub const TEST_CONTEXT_ID: &str = "test-context-id";
+pub const TEST_CONTEXT_ID: &str = "00000000-0000-4000-8000-000000000001";
 
 pub fn get_example_happy_placement_config() -> Vec<MozAdsPlacementConfig> {
     vec![

components/ads-client/src/test_utils.rs

@@ -31,7 +31,6 @@ impl ContextIDComponent {
     ///
     /// If no creation timestamp is provided, the current time will be used.
     #[uniffi::constructor]
-
     pub fn new(
         init_context_id: &str,
         creation_timestamp_s: i64,