mk-sql adds headers to the error message

Previously, the mk-sql plugin would send only error text when
an error occurred, which could disrupt other services.
Now, in the event of an error, the mk-sql plugin always sends
SQL plain headers, thereby eliminating this problem.

Change-Id: I91146955c6139941527b59b81e378b2b07e9c2a8

packages/mk-sql/src/ms_sql/instance.rs

@@ -1467,7 +1467,8 @@ fn generate_signaling_block(
 async fn generate_data(ms_sql: &config::ms_sql::Config, environment: &Env) -> Result<String> {
     let instances = find_usable_instances(ms_sql, environment).await?;
     if instances.is_empty() {
-        return Ok("ERROR: Failed to gather SQL server instances\n".to_string());
+        return Ok(generate_signaling_block(ms_sql, &None)
+            + "ERROR: Failed to gather SQL server instances\n");
     } else {
         log::info!(
             "Found {} SQL server instances: [ {} ]",

packages/mk-sql/tests/test_ms_sql.rs

@@ -1189,6 +1189,38 @@ async fn test_check_config_exec_piggyback_remote() {
     assert!(!output.is_empty());
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn test_lack_of_sql_db() {
+    let dir = tools::create_temp_process_dir();
+    let content = std::fs::read_to_string(
+        PathBuf::new()
+            .join("tests")
+            .join("files")
+            .join("test-no-ms-sql.yml"),
+    )
+    .unwrap();
+    tools::create_file_with_content(dir.path(), "mk-sql.yml", &content);
+    let check_config = CheckConfig::load_file(&dir.path().join("mk-sql.yml")).unwrap();
+    let output = check_config.exec(&Env::default()).await.unwrap();
+    let awaited = "<<<mssql_instance:sep(124)>>>
+<<<mssql_databases:sep(124)>>>
+<<<mssql_counters:sep(124)>>>
+<<<mssql_blocked_sessions:sep(124)>>>
+<<<mssql_transactionlogs:sep(124)>>>
+<<<mssql_clusters:sep(124)>>>
+<<<mssql_mirroring:sep(09)>>>
+<<<mssql_availability_groups:sep(09)>>>
+<<<mssql_connections>>>
+<<<mssql_tablespaces>>>
+<<<mssql_datafiles:sep(124)>>>
+<<<mssql_backup:sep(124)>>>
+<<<mssql_jobs:sep(09)>>>
+<<<mssql_instance:sep(124)>>>
+ERROR: Failed to gather SQL server instances\n"
+        .to_owned();
+    assert_eq!(output.to_owned(), awaited);
+}
+
 #[cfg(windows)]
 fn create_localhost_remote_config(endpoint: SqlDbEndpoint) -> String {
     format!(