Fix: Terraform resource names can't start with digits, but BQ tables can

scripts/generate_terraform.py

@@ -203,6 +203,14 @@ def customize_template_subs(resource: dict, subs: dict) -> dict:
         subs["uniform_bucket_level_access"] = resource.get(
             "uniform_bucket_level_access"
         )
+    elif resource["type"] == "bigquery_table":
+        # Terraform resource names cannot start with digits, but BigQuery allows
+        # table names that start with digits. We prepend `bqt_` to table names
+        # that doesn't comply with Terraform's naming rule.
+        if resource["table_id"][0].isdigit():
+            subs["tf_resource_name"] = "bqt_" + resource["table_id"]
+        else:
+            subs["tf_resource_name"] = resource["table_id"]
     return subs
 
 

templates/terraform/google_bigquery_table.tf.jinja2

@@ -15,7 +15,7 @@
  */
 
 
-resource "google_bigquery_table" "{{ table_id }}" {
+resource "google_bigquery_table" "{{ tf_resource_name }}" {
   project    = var.project_id
   dataset_id = "{{ dataset_id }}"
   table_id   = "{{ table_id }}"
@@ -34,9 +34,9 @@ resource "google_bigquery_table" "{{ table_id }}" {
 }
 
 output "bigquery_table-{{ table_id }}-table_id" {
-  value = google_bigquery_table.{{ table_id }}.table_id
+  value = google_bigquery_table.{{ tf_resource_name }}.table_id
 }
 
 output "bigquery_table-{{ table_id }}-id" {
-  value = google_bigquery_table.{{ table_id }}.id
+  value = google_bigquery_table.{{ tf_resource_name }}.id
 }

tests/scripts/test_generate_terraform.py

@@ -14,6 +14,7 @@
 
 
 import pathlib
+import random
 import re
 import shutil
 import subprocess
@@ -584,6 +585,72 @@ def test_pipeline_tf_has_no_bq_table_description_when_unspecified(
         assert not re.search(r"description\s+\=", result.group(1))
 
 
+def test_bq_table_name_starts_with_digits_but_tf_resource_name_does_not(
+    dataset_path,
+    pipeline_path,
+    project_id,
+    bucket_name_prefix,
+    region,
+    impersonating_acct,
+    env,
+):
+    shutil.copyfile(SAMPLE_YAML_PATHS["dataset"], dataset_path / "dataset.yaml")
+    shutil.copyfile(SAMPLE_YAML_PATHS["pipeline"], pipeline_path / "pipeline.yaml")
+
+    config = yaml.load(open(pipeline_path / "pipeline.yaml"))
+    table_name_starting_with_digit = f"{str(random.randint(0, 9))}_table"
+
+    # In the YAML config, set the BigQuery table name to start with a digit
+    bq_table = next(
+        (r for r in config["resources"] if r["type"] == "bigquery_table"), None
+    )
+    bq_table["table_id"] = table_name_starting_with_digit
+    with open(pipeline_path / "pipeline.yaml", "w") as file:
+        yaml.dump(config, file)
+
+    generate_terraform.main(
+        dataset_path.name,
+        project_id,
+        bucket_name_prefix,
+        region,
+        impersonating_acct,
+        env,
+        None,
+        None,
+    )
+
+    # Match the Terraform resource name and the table_id value in the BigQuery
+    # table's resource definition. As a concrete example, substrings in
+    # ALL_CAPS are matched below:
+    #
+    # resource "google_bigquery_table" "RESOURCE_NAME_STARTING_WITH_NONDIGIT" {
+    #   description = ""
+    #   table_id    = "TABLE_NAME_STARTING_WITH_DIGIT"
+    # }
+    tf_resource_regexp = r"\"google_bigquery_table\" \"([a-zA-Z0-9_-]+)\" .*?"
+    table_id_regexp = r"table_id\s+\= \"(.*?)\"\n"
+    matcher = re.compile(
+        tf_resource_regexp + table_id_regexp,
+        flags=re.MULTILINE | re.DOTALL,
+    )
+
+    for path_prefix in (
+        ENV_DATASETS_PATH / dataset_path.name / "_terraform",
+        generate_terraform.DATASETS_PATH / dataset_path.name / "_terraform",
+    ):
+        result = matcher.search(
+            (path_prefix / f"{pipeline_path.name}_pipeline.tf").read_text()
+        )
+
+        tf_resource_name = result.group(1)
+        table_id = result.group(2)
+
+        assert table_id == table_name_starting_with_digit
+        assert not tf_resource_name[0].isdigit()
+        assert table_id[0].isdigit()
+        assert table_id in tf_resource_name
+
+
 def test_bucket_names_must_not_contain_dots_and_google():
     for name in (
         "test.bucket.name",