Support BigQuery custom schema's for external data using CSV / NDJSON

.changelog/3717.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+bigquery: added support for BigQuery custom schemas for external data using CSV / NDJSON 
+```

google/resource_bigquery_table.go

@@ -109,6 +109,21 @@ func resourceBigQueryTable() *schema.Resource {
 							Default:      "NONE",
 							Description:  `The compression type of the data source. Valid values are "NONE" or "GZIP".`,
 						},
+						// Schema: Optional] The schema for the  data.
+						// Schema is required for CSV and JSON formats if autodetect is not on.
+						// Schema is disallowed for Google Cloud Bigtable, Cloud Datastore backups, Avro, ORC and Parquet formats.
+						"schema": {
+							Type:         schema.TypeString,
+							Optional:     true,
+							Computed:     true,
+							ForceNew:     true,
+							ValidateFunc: validation.ValidateJsonString,
+							StateFunc: func(v interface{}) string {
+								json, _ := structure.NormalizeJsonString(v)
+								return json
+							},
+							Description: `A JSON schema for the external table. Schema is required for CSV and JSON formats and is disallowed for Google Cloud Bigtable, Cloud Datastore backups, and Avro formats when using external tables.`,
+						},
 						// CsvOptions: [Optional] Additional properties to set if
 						// sourceFormat is set to CSV.
 						"csv_options": {
@@ -275,9 +290,6 @@ func resourceBigQueryTable() *schema.Resource {
 			},
 
 			// Schema: [Optional] Describes the schema of this table.
-			// Schema is required for external tables in CSV and JSON formats
-			// and disallowed for Google Cloud Bigtable, Cloud Datastore backups,
-			// and Avro formats.
 			"schema": {
 				Type:         schema.TypeString,
 				Optional:     true,
@@ -287,7 +299,7 @@ func resourceBigQueryTable() *schema.Resource {
 					json, _ := structure.NormalizeJsonString(v)
 					return json
 				},
-				Description: `A JSON schema for the table. Schema is required for CSV and JSON formats and is disallowed for Google Cloud Bigtable, Cloud Datastore backups, and Avro formats when using external tables.`,
+				Description: `A JSON schema for the table.`,
 			},
 
 			// View: [Optional] If specified, configures this table as a view.
@@ -636,7 +648,6 @@ func resourceBigQueryTableCreate(d *schema.ResourceData, meta interface{}) error
 	}
 
 	log.Printf("[INFO] BigQuery table %s has been created", res.Id)
-
 	d.SetId(fmt.Sprintf("projects/%s/datasets/%s/tables/%s", res.TableReference.ProjectId, res.TableReference.DatasetId, res.TableReference.TableId))
 
 	return resourceBigQueryTableRead(d, meta)
@@ -683,6 +694,24 @@ func resourceBigQueryTableRead(d *schema.ResourceData, meta interface{}) error {
 			return err
 		}
 
+		if v, ok := d.GetOk("external_data_configuration"); ok {
+			// The API response doesn't return the `external_data_configuration.schema`
+			// used when creating the table and it cannot be queried.
+			// After creation, a computed schema is stored in the toplevel `schema`,
+			// which combines `external_data_configuration.schema`
+			// with any hive partioning fields found in the `source_uri_prefix`.
+			// So just assume the configured schema has been applied after successful
+			// creation, by copying the configured value back into the resource schema.
+			// This avoids that reading back this field will be identified as a change.
+			// The `ForceNew=true` on `external_data_configuration.schema` will ensure
+			// the users' expectation that changing the configured  input schema will
+			// recreate the resource.
+			edc := v.([]interface{})[0].(map[string]interface{})
+			if edc["schema"] != nil {
+				externalDataConfiguration[0]["schema"] = edc["schema"]
+			}
+		}
+
 		d.Set("external_data_configuration", externalDataConfiguration)
 	}
 
@@ -804,6 +833,13 @@ func expandExternalDataConfiguration(cfg interface{}) (*bigquery.ExternalDataCon
 	if v, ok := raw["max_bad_records"]; ok {
 		edc.MaxBadRecords = int64(v.(int))
 	}
+	if v, ok := raw["schema"]; ok {
+		schema, err := expandSchema(v)
+		if err != nil {
+			return nil, err
+		}
+		edc.Schema = schema
+	}
 	if v, ok := raw["source_format"]; ok {
 		edc.SourceFormat = v.(string)
 	}

google/resource_bigquery_table_test.go

@@ -119,6 +119,31 @@ func TestAccBigQueryTable_HivePartitioning(t *testing.T) {
 	})
 }
 
+func TestAccBigQueryTable_HivePartitioningCustomSchema(t *testing.T) {
+	t.Parallel()
+	bucketName := testBucketName(t)
+	resourceName := "google_bigquery_table.test"
+	datasetID := fmt.Sprintf("tf_test_%s", randString(t, 10))
+	tableID := fmt.Sprintf("tf_test_%s", randString(t, 10))
+
+	vcrTest(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckBigQueryTableDestroyProducer(t),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccBigQueryTableHivePartitioningCustomSchema(bucketName, datasetID, tableID),
+			},
+			{
+				ResourceName:            resourceName,
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"external_data_configuration.0.schema"},
+			},
+		},
+	})
+}
+
 func TestAccBigQueryTable_RangePartitioning(t *testing.T) {
 	t.Parallel()
 	resourceName := "google_bigquery_table.test"
@@ -480,23 +505,72 @@ resource "google_storage_bucket_object" "test" {
 }
 
 resource "google_bigquery_dataset" "test" {
-        dataset_id = "%s"
+	dataset_id = "%s"
 }
 
 resource "google_bigquery_table" "test" {
 	table_id   = "%s"
 	dataset_id = google_bigquery_dataset.test.dataset_id
 
 	external_data_configuration {
-            source_format = "CSV"
-            autodetect = true
-            source_uris= ["gs://${google_storage_bucket.test.name}/*"]
+		source_format = "CSV"
+		autodetect = true
+		source_uris= ["gs://${google_storage_bucket.test.name}/*"]
 
-            hive_partitioning_options {
-                mode = "AUTO"
-                source_uri_prefix = "gs://${google_storage_bucket.test.name}/"
-	    }
+		hive_partitioning_options {
+			mode = "AUTO"
+			source_uri_prefix = "gs://${google_storage_bucket.test.name}/"
+		}
 
+	}
+	depends_on = ["google_storage_bucket_object.test"]
+}
+`, bucketName, datasetID, tableID)
+}
+
+func testAccBigQueryTableHivePartitioningCustomSchema(bucketName, datasetID, tableID string) string {
+	return fmt.Sprintf(`
+resource "google_storage_bucket" "test" {
+	name          = "%s"
+	force_destroy = true
+}
+
+resource "google_storage_bucket_object" "test" {
+	name    = "key1=20200330/data.json"
+	content = "{\"name\":\"test\", \"last_modification\":\"2020-04-01\"}"
+	bucket  = google_storage_bucket.test.name
+}
+
+resource "google_bigquery_dataset" "test" {
+	dataset_id = "%s"
+}
+
+resource "google_bigquery_table" "test" {
+	table_id   = "%s"
+	dataset_id = google_bigquery_dataset.test.dataset_id
+
+	external_data_configuration {
+		source_format = "NEWLINE_DELIMITED_JSON"
+		autodetect = false
+		source_uris= ["gs://${google_storage_bucket.test.name}/*"]
+
+		hive_partitioning_options {
+			mode = "CUSTOM"
+			source_uri_prefix = "gs://${google_storage_bucket.test.name}/{key1:STRING}"
+		}
+
+		schema = <<EOH
+[
+	{
+		"name": "name",
+		"type": "STRING"
+	},
+	{
+		"name": "last_modification",
+		"type": "DATE"
+	}
+]
+EOH
         }
 	depends_on = ["google_storage_bucket_object.test"]
 }

website/docs/r/bigquery_table.html.markdown

@@ -112,11 +112,7 @@ The following arguments are supported:
 
 * `labels` - (Optional) A mapping of labels to assign to the resource.
 
-* `schema` - (Optional) A JSON schema for the table. Schema is required
-    for CSV and JSON formats and is disallowed for Google Cloud
-    Bigtable, Cloud Datastore backups, and Avro formats when using
-    external tables. For more information see the
-    [BigQuery API documentation](https://cloud.google.com/bigquery/docs/reference/rest/v2/tables#resource).
+* `schema` - (Optional) A JSON schema for the table.
     ~>**NOTE**: Because this field expects a JSON string, any changes to the
     string will create a diff, even if the JSON itself hasn't changed.
     If the API returns a different value for the same schema, e.g. it
@@ -167,6 +163,18 @@ The `external_data_configuration` block supports:
 * `max_bad_records` (Optional) - The maximum number of bad records that
     BigQuery can ignore when reading data.
 
+* `schema` - (Optional) A JSON schema for the external table. Schema is required
+    for CSV and JSON formats if autodetect is not on. Schema is disallowed
+    for Google Cloud Bigtable, Cloud Datastore backups, Avro, ORC and Parquet formats.
+    ~>**NOTE**: Because this field expects a JSON string, any changes to the
+    string will create a diff, even if the JSON itself hasn't changed.
+    Furthermore drift for this field cannot not be detected because BigQuery
+    only uses this schema to compute the effective schema for the table, therefore
+    any changes on the configured value will force the table to be recreated.
+    This schema is effectively only applied when creating a table from an external
+    datasource, after creation the computed schema will be stored in
+    `google_bigquery_table.schema`
+
 * `source_format` (Required) - The data format. Supported values are:
     "CSV", "GOOGLE_SHEETS", "NEWLINE_DELIMITED_JSON", "AVRO", "PARQUET",
     and "DATSTORE_BACKUP". To use "GOOGLE_SHEETS"