feat: restart tedge-agent on tedge connect

crates/common/tedge_config/src/system_services/manager_ext.rs

@@ -4,6 +4,7 @@ use anyhow::Context as _;
 /// Extension trait for `SystemServiceManager`.
 pub trait SystemServiceManagerExt {
     fn start_and_enable_service(&self, service: SystemService<'_>) -> anyhow::Result<()>;
+    fn restart_and_enable_service(&self, service: SystemService<'_>) -> anyhow::Result<()>;
     fn stop_and_disable_service(&self, service: SystemService<'_>) -> anyhow::Result<()>;
 }
 
@@ -15,6 +16,13 @@ impl SystemServiceManagerExt for &dyn SystemServiceManager {
             .with_context(|| format!("Failed to enable {service}"))
     }
 
+    fn restart_and_enable_service(&self, service: SystemService<'_>) -> anyhow::Result<()> {
+        self.restart_service(service)
+            .with_context(|| format!("Failed to start {service}"))?;
+        self.enable_service(service)
+            .with_context(|| format!("Failed to enable {service}"))
+    }
+
     fn stop_and_disable_service(&self, service: SystemService<'_>) -> anyhow::Result<()> {
         self.stop_service(service)
             .with_context(|| format!("Failed to stop {service}"))?;

crates/core/tedge/src/cli/connect/command.rs

@@ -1012,8 +1012,10 @@ fn enable_software_management(
     if bridge_config.use_agent {
         if which("tedge-agent").is_ok() {
             let spinner = Spinner::start("Enabling tedge-agent");
+            // Restart the agent in case it is already running
+            // and so it picks up the latest settings (e.g. updated mqtt port)
             let _ = spinner
-                .finish(service_manager.start_and_enable_service(SystemService::TEdgeSMAgent));
+                .finish(service_manager.restart_and_enable_service(SystemService::TEdgeSMAgent));
         } else {
             println!("Info: Software management is not installed. So, skipping enabling related components.\n");
         }

tests/RobotFramework/tests/tedge_connect/tedge_connect_change_config.robot

@@ -0,0 +1,34 @@
+*** Settings ***
+Resource            ../../resources/common.resource
+Library             ThinEdgeIO
+
+Test Setup          Test Setup
+Test Teardown       Get Logs
+
+Test Tags           theme:cli    theme:mqtt    theme:c8y
+
+
+*** Test Cases ***
+Restart agent on connection
+    [Documentation]    tedge connect/reconnect should restart tedge-agent service to ensure it has the latest settings
+
+    Service Should Be Running    tedge-agent
+    ${agent_pid_before}    Execute Command    sudo systemctl show --property MainPID tedge-agent
+
+    # Change some configuration
+    Execute Command
+    ...    tedge config unset mqtt.client.auth.ca_file && tedge config unset mqtt.client.auth.cert_file && tedge config unset mqtt.client.auth.key_file
+    Execute Command    tedge config set mqtt.bind.port 1884 && tedge config set mqtt.client.port 1884
+
+    Execute Command    sudo tedge reconnect c8y
+    Execute Command    sudo tedge connect c8y --test
+    ${agent_pid_after}    Execute Command    sudo systemctl show --property MainPID tedge-agent
+    Should Not Be Equal    ${agent_pid_before}    ${agent_pid_after}
+
+    Service Should Be Running    tedge-agent
+    Service Health Status Should Be Up    tedge-agent
+
+
+*** Keywords ***
+Test Setup
+    Setup