C8y mapping of entity registration messages

crates/common/tedge_config/src/tedge_config_cli/tedge_config.rs

@@ -369,7 +369,7 @@ define_tedge_config! {
 
         /// Set of MQTT topics the Cumulocity mapper should subscribe to
         #[tedge_config(example = "te/+/+/+/+/a/+,te/+/+/+/+/m/+,te/+/+/+/+/e/+")]
-        #[tedge_config(default(value = "te/+/+/+/+/m/+,te/+/+/+/+/e/+,te/+/+/+/+/a/+,tedge/health/+,tedge/health/+/+"))]
+        #[tedge_config(default(value = "te/+/+/+/+,te/+/+/+/+/m/+,te/+/+/+/+/e/+,te/+/+/+/+/a/+,tedge/health/+,tedge/health/+/+"))]
         topics: TemplatesSet,
 
         enable: {

crates/core/c8y_api/src/json_c8y.rs

@@ -319,8 +319,8 @@ impl C8yAlarm {
     fn convert_source(entity: &EntityMetadata) -> Option<SourceInfo> {
         match entity.r#type {
             EntityType::MainDevice => None,
-            EntityType::ChildDevice => Some(make_c8y_source_fragment(&entity.entity_id.clone())),
-            EntityType::Service => Some(make_c8y_source_fragment(&entity.entity_id.clone())),
+            EntityType::ChildDevice => Some(make_c8y_source_fragment(entity.external_id.as_ref())),
+            EntityType::Service => Some(make_c8y_source_fragment(entity.external_id.as_ref())),
         }
     }
 
@@ -415,6 +415,7 @@ mod tests {
     use serde_json::json;
     use tedge_api::alarm::ThinEdgeAlarm;
     use tedge_api::alarm::ThinEdgeAlarmData;
+    use tedge_api::entity_store::EntityExternalId;
     use tedge_api::entity_store::EntityRegistrationMessage;
     use tedge_api::event::ThinEdgeEventData;
     use tedge_api::mqtt_topics::EntityTopicId;
@@ -774,7 +775,8 @@ mod tests {
     )]
     fn check_alarm_translation(tedge_alarm: ThinEdgeAlarm, expected_c8y_alarm: C8yAlarm) {
         let main_device = EntityRegistrationMessage::main_device("test-main".into());
-        let mut entity_store = EntityStore::with_main_device(main_device).unwrap();
+        let mut entity_store =
+            EntityStore::with_main_device(main_device, dummy_external_id_mapper).unwrap();
 
         let child_registration = EntityRegistrationMessage::new(&Message::new(
             &Topic::new_unchecked("te/device/external_source//"),
@@ -801,7 +803,8 @@ mod tests {
         };
 
         let main_device = EntityRegistrationMessage::main_device("test-main".into());
-        let entity_store = EntityStore::with_main_device(main_device).unwrap();
+        let entity_store =
+            EntityStore::with_main_device(main_device, dummy_external_id_mapper).unwrap();
 
         match C8yAlarm::try_from(&tedge_alarm, &entity_store).unwrap() {
             C8yAlarm::Create(value) => {
@@ -810,4 +813,15 @@ mod tests {
             C8yAlarm::Clear(_) => panic!("Must be C8yAlarm::Create"),
         };
     }
+
+    fn dummy_external_id_mapper(
+        entity_topic_id: &EntityTopicId,
+        _main_device_xid: &EntityExternalId,
+    ) -> EntityExternalId {
+        entity_topic_id
+            .to_string()
+            .trim_end_matches('/')
+            .replace('/', ":")
+            .into()
+    }
 }

crates/core/c8y_api/src/smartrest/inventory.rs

@@ -0,0 +1,43 @@
+//! This module provides some helper functions to create SmartREST messages
+//! that can be used to create various managed objects in Cumulocity inventory.
+use crate::smartrest::topic::publish_topic_from_ancestors;
+use mqtt_channel::Message;
+
+/// Create a SmartREST message for creating a child device under the given ancestors.
+/// The provided ancestors list must contain all the parents of the given device
+/// starting from its immediate parent device.
+pub fn child_device_creation_message(
+    child_id: &str,
+    device_name: Option<&str>,
+    device_type: Option<&str>,
+    ancestors: &[String],
+) -> Message {
+    Message::new(
+        &publish_topic_from_ancestors(ancestors),
+        format!(
+            "101,{},{},{}",
+            child_id,
+            device_name.unwrap_or(child_id),
+            device_type.unwrap_or("thin-edge.io-child")
+        ),
+    )
+}
+
+/// Create a SmartREST message for creating a service on device.
+/// The provided ancestors list must contain all the parents of the given service
+/// starting from its immediate parent device.
+pub fn service_creation_message(
+    service_id: &str,
+    service_name: &str,
+    service_type: &str,
+    service_status: &str,
+    ancestors: &[String],
+) -> Message {
+    Message::new(
+        &publish_topic_from_ancestors(ancestors),
+        format!(
+            "102,{},{},{},{}",
+            service_id, service_type, service_name, service_status
+        ),
+    )
+}

crates/core/c8y_api/src/smartrest/mod.rs

@@ -1,5 +1,6 @@
 pub mod alarm;
 pub mod error;
+pub mod inventory;
 pub mod message;
 pub mod operations;
 pub mod smartrest_deserializer;

crates/core/c8y_api/src/smartrest/topic.rs

@@ -24,7 +24,7 @@ impl C8yTopic {
         match entity.r#type {
             EntityType::MainDevice => Some(C8yTopic::upstream_topic()),
             EntityType::ChildDevice | EntityType::Service => {
-                Self::ChildSmartRestResponse(entity.entity_id.clone())
+                Self::ChildSmartRestResponse(entity.external_id.clone().into())
                     .to_topic()
                     .ok()
             }
@@ -103,17 +103,6 @@ impl From<C8yTopic> for TopicFilter {
     }
 }
 
-// FIXME this From conversion is error prone as this can only be used for responses.
-impl From<&EntityMetadata> for C8yTopic {
-    fn from(value: &EntityMetadata) -> Self {
-        match value.r#type {
-            EntityType::MainDevice => Self::SmartRestResponse,
-            EntityType::ChildDevice => Self::ChildSmartRestResponse(value.entity_id.clone()),
-            EntityType::Service => Self::SmartRestResponse, // TODO how services are handled by c8y?
-        }
-    }
-}
-
 impl From<&C8yAlarm> for C8yTopic {
     fn from(value: &C8yAlarm) -> Self {
         match value {
@@ -164,10 +153,35 @@ impl TryFrom<Topic> for MapperSubscribeTopic {
     }
 }
 
+/// Generates the SmartREST topic to publish to, for a given managed object
+/// from the list of external IDs of itself and all its parents.
+///
+/// The parents are appended in the reverse order,
+/// starting from the main device at the end of the list.
+/// The main device itself is represented by the root topic c8y/s/us,
+/// with the rest of the children appended to it at each topic level.
+///
+/// # Examples
+///
+/// - `["main"]` -> `c8y/s/us`
+/// - `["child1", "main"]` -> `c8y/s/us/child1`
+/// - `["child2", "child1", "main"]` -> `c8y/s/us/child1/child2`
+pub fn publish_topic_from_ancestors(ancestors: &[String]) -> Topic {
+    let mut target_topic = SMARTREST_PUBLISH_TOPIC.to_string();
+    for ancestor in ancestors.iter().rev().skip(1) {
+        // Skipping the last ancestor as it is the main device represented by the root topic itself
+        target_topic.push('/');
+        target_topic.push_str(ancestor);
+    }
+
+    Topic::new_unchecked(&target_topic)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use std::convert::TryInto;
+    use test_case::test_case;
 
     #[test]
     fn convert_c8y_topic_to_str() {
@@ -211,4 +225,14 @@ mod tests {
         let error: Result<C8yTopic, TopicError> = Topic::new("test").unwrap().try_into();
         assert!(error.is_err());
     }
+
+    #[test_case(&["main"], "c8y/s/us")]
+    #[test_case(&["foo"], "c8y/s/us")]
+    #[test_case(&["child1", "main"], "c8y/s/us/child1")]
+    #[test_case(&["child3", "child2", "child1", "main"], "c8y/s/us/child1/child2/child3")]
+    fn topic_from_ancestors(ancestors: &[&str], topic: &str) {
+        let ancestors: Vec<String> = ancestors.iter().map(|v| v.to_string()).collect();
+        let nested_child_topic = publish_topic_from_ancestors(&ancestors);
+        assert_eq!(nested_child_topic, Topic::new_unchecked(topic));
+    }
 }