feat: add option to skip table creation in azure data explorer output (…

…#9942)

plugins/outputs/azure_data_explorer/README.md

@@ -31,6 +31,10 @@ Azure Data Explorer is a distributed, columnar store, purpose built for any type
 
   ## Name of the single table to store all the metrics (Only needed if metrics_grouping_type is "SingleTable").
   # table_name = ""
+
+  ## Creates tables and relevant mapping if set to true(default). 
+  ## Skips table and mapping creation if set to false, this is useful for running Telegraf with the lowest possible permissions i.e. table ingestor role.
+  # create_tables = true
 ```
 
 ## Metrics Grouping
@@ -85,7 +89,10 @@ These methods are:
 
 [principal]: https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-application-objects
 
-Whichever method, the designated Principal needs to be assigned the `Database User` role on the Database level in the Azure Data Explorer. This role will allow the plugin to create the required tables and ingest data into it.
+Whichever method, the designated Principal needs to be assigned the `Database User` role on the Database level in the Azure Data Explorer. This role will 
+allow the plugin to create the required tables and ingest data into it.  
+If `create_tables=false` then the designated principal only needs the `Database Ingestor` role at least.
+
 
 ### Configurations of the chosen Authentication Method 
 

plugins/outputs/azure_data_explorer/azure_data_explorer.go

@@ -27,6 +27,7 @@ type AzureDataExplorer struct {
 	Timeout         config.Duration `toml:"timeout"`
 	MetricsGrouping string          `toml:"metrics_grouping_type"`
 	TableName       string          `toml:"table_name"`
+	CreateTables    bool            `toml:"create_tables"`
 	client          localClient
 	ingesters       map[string]localIngestor
 	serializer      serializers.Serializer
@@ -57,7 +58,7 @@ func (adx *AzureDataExplorer) Description() string {
 
 func (adx *AzureDataExplorer) SampleConfig() string {
 	return `
-  ## Azure Data Exlorer cluster endpoint
+  ## Azure Data Explorer cluster endpoint
   ## ex: endpoint_url = "https://clustername.australiasoutheast.kusto.windows.net"
   endpoint_url = ""
   
@@ -77,6 +78,9 @@ func (adx *AzureDataExplorer) SampleConfig() string {
   ## Name of the single table to store all the metrics (Only needed if metrics_grouping_type is "SingleTable").
   # table_name = ""
 
+  ## Creates tables and relevant mapping if set to true(default). 
+  ## Skips table and mapping creation if set to false, this is useful for running Telegraf with the lowest possible permissions i.e. table ingestor role.
+  # create_tables = true
 `
 }
 
@@ -198,6 +202,10 @@ func (adx *AzureDataExplorer) getIngestor(ctx context.Context, tableName string)
 }
 
 func (adx *AzureDataExplorer) createAzureDataExplorerTable(ctx context.Context, tableName string) error {
+	if !adx.CreateTables {
+		adx.Log.Info("skipped table creation")
+		return nil
+	}
 	createStmt := kusto.NewStmt("", kusto.UnsafeStmt(unsafe.Stmt{Add: true, SuppressWarning: true})).UnsafeAdd(fmt.Sprintf(createTableCommand, tableName))
 	if _, err := adx.client.Mgmt(ctx, adx.Database, createStmt); err != nil {
 		return err
@@ -241,7 +249,8 @@ func (adx *AzureDataExplorer) Init() error {
 func init() {
 	outputs.Add("azure_data_explorer", func() telegraf.Output {
 		return &AzureDataExplorer{
-			Timeout: config.Duration(20 * time.Second),
+			Timeout:      config.Duration(20 * time.Second),
+			CreateTables: true,
 		}
 	})
 }

plugins/outputs/azure_data_explorer/azure_data_explorer_test.go

@@ -31,10 +31,12 @@ func TestWrite(t *testing.T) {
 		tableName          string
 		expected           map[string]interface{}
 		expectedWriteError string
+		createTables       bool
 	}{
 		{
-			name:        "Valid metric",
-			inputMetric: testutil.MockMetrics(),
+			name:         "Valid metric",
+			inputMetric:  testutil.MockMetrics(),
+			createTables: true,
 			client: &fakeClient{
 				queries: make([]string, 0),
 				internalMgmt: func(f *fakeClient, ctx context.Context, db string, query kusto.Stmt, options ...kusto.MgmtOption) (*kusto.RowIterator, error) {
@@ -56,8 +58,34 @@ func TestWrite(t *testing.T) {
 			},
 		},
 		{
-			name:        "Error in Mgmt",
-			inputMetric: testutil.MockMetrics(),
+			name:         "Don't create tables'",
+			inputMetric:  testutil.MockMetrics(),
+			createTables: false,
+			client: &fakeClient{
+				queries: make([]string, 0),
+				internalMgmt: func(f *fakeClient, ctx context.Context, db string, query kusto.Stmt, options ...kusto.MgmtOption) (*kusto.RowIterator, error) {
+					require.Fail(t, "Mgmt shouldn't be called when create_tables is false")
+					f.queries = append(f.queries, query.String())
+					return &kusto.RowIterator{}, nil
+				},
+			},
+			createIngestor:  createFakeIngestor,
+			metricsGrouping: tablePerMetric,
+			expected: map[string]interface{}{
+				"metricName": "test1",
+				"fields": map[string]interface{}{
+					"value": 1.0,
+				},
+				"tags": map[string]interface{}{
+					"tag1": "value1",
+				},
+				"timestamp": float64(time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC).UnixNano() / int64(time.Second)),
+			},
+		},
+		{
+			name:         "Error in Mgmt",
+			inputMetric:  testutil.MockMetrics(),
+			createTables: true,
 			client: &fakeClient{
 				queries: make([]string, 0),
 				internalMgmt: func(f *fakeClient, ctx context.Context, db string, query kusto.Stmt, options ...kusto.MgmtOption) (*kusto.RowIterator, error) {
@@ -79,8 +107,9 @@ func TestWrite(t *testing.T) {
 			expectedWriteError: "creating table for \"test1\" failed: Something went wrong",
 		},
 		{
-			name:        "SingleTable metric grouping type",
-			inputMetric: testutil.MockMetrics(),
+			name:         "SingleTable metric grouping type",
+			inputMetric:  testutil.MockMetrics(),
+			createTables: true,
 			client: &fakeClient{
 				queries: make([]string, 0),
 				internalMgmt: func(f *fakeClient, ctx context.Context, db string, query kusto.Stmt, options ...kusto.MgmtOption) (*kusto.RowIterator, error) {
@@ -114,6 +143,7 @@ func TestWrite(t *testing.T) {
 				Log:             testutil.Logger{},
 				MetricsGrouping: tC.metricsGrouping,
 				TableName:       tC.tableName,
+				CreateTables:    tC.createTables,
 				client:          tC.client,
 				ingesters:       map[string]localIngestor{},
 				createIngestor:  tC.createIngestor,
@@ -149,11 +179,15 @@ func TestWrite(t *testing.T) {
 				expectedTime := tC.expected["timestamp"].(float64)
 				require.Equal(t, expectedTime, createdFakeIngestor.actualOutputMetric["timestamp"])
 
-				createTableString := fmt.Sprintf(createTableCommandExpected, expectedNameOfTable)
-				require.Equal(t, createTableString, tC.client.queries[0])
+				if tC.createTables {
+					createTableString := fmt.Sprintf(createTableCommandExpected, expectedNameOfTable)
+					require.Equal(t, createTableString, tC.client.queries[0])
 
-				createTableMappingString := fmt.Sprintf(createTableMappingCommandExpected, expectedNameOfTable, expectedNameOfTable)
-				require.Equal(t, createTableMappingString, tC.client.queries[1])
+					createTableMappingString := fmt.Sprintf(createTableMappingCommandExpected, expectedNameOfTable, expectedNameOfTable)
+					require.Equal(t, createTableMappingString, tC.client.queries[1])
+				} else {
+					require.Empty(t, tC.client.queries)
+				}
 			}
 		})
 	}
@@ -185,10 +219,10 @@ type fakeIngestor struct {
 	actualOutputMetric map[string]interface{}
 }
 
-func createFakeIngestor(client localClient, database string, tableName string) (localIngestor, error) {
+func createFakeIngestor(localClient, string, string) (localIngestor, error) {
 	return &fakeIngestor{}, nil
 }
-func (f *fakeIngestor) FromReader(ctx context.Context, reader io.Reader, options ...ingest.FileOption) (*ingest.Result, error) {
+func (f *fakeIngestor) FromReader(_ context.Context, reader io.Reader, _ ...ingest.FileOption) (*ingest.Result, error) {
 	scanner := bufio.NewScanner(reader)
 	scanner.Scan()
 	firstLine := scanner.Text()