Add table replace mode

Change-Id: I1f66c445413b89e53b69e81deb2b3ac5f8ca0465

README.md

@@ -139,6 +139,7 @@ If you change the schema in Bigquery, Argon's schema check will fail.
       "projectId": "[BIGQUERY_PROJECT]", // default: current cloud project
       "single": [SINGLE_FILE_MODE], // default: true
       "ignore": [IGNORE_FILE_IDS], // default: []
+      "replace": [REPLACE_TABLE_MODE], // default: false, append only
       "email": "[EMAIL_ADDRESS]" // default: no impersonation
     }
     ```
@@ -155,6 +156,9 @@ If you change the schema in Bigquery, Argon's schema check will fail.
   - Set `ignore` to a list of Report File IDs, to skip wrongly generated
     or unnecessary report files.
 
+  - Set `replace` to true, to replace the BigQuery table on running,
+    instead of appending to it.
+
   - Set `email` to a Service Account email address, to impersonate it
     for local development or testing purposes.
 
@@ -275,7 +279,7 @@ npm run format
 
 #### Docker
 
-Argon can be containerised using [Pack](https://buildpacks.io/docs/tools/pack).
+Argon can be containerized using [Pack](https://buildpacks.io/docs/tools/pack).
 
 ```sh
 # Build & Run a Docker image, from your local source

src/helpers.ts

@@ -119,7 +119,10 @@ function isSupportedProduct(product: string): product is SupportedProduct {
   return product === 'CM' || product === 'DV';
 }
 
-type DefaultArgonOpts = Pick<ArgonOpts, 'projectId' | 'single' | 'ignore'>;
+type DefaultArgonOpts = Pick<
+  ArgonOpts,
+  'projectId' | 'single' | 'ignore' | 'replace'
+>;
 
 /**
  * Get a partially filled ArgonOpts with sane defaults.
@@ -132,6 +135,7 @@ async function getDefaultArgonOpts(): Promise<DefaultArgonOpts> {
     projectId: await getProjectId(),
     single: true,
     ignore: [],
+    replace: false,
   };
 }
 
@@ -230,6 +234,16 @@ export async function parseBody(body: ParsedJSON): Promise<ArgonOpts> {
     warn(`Ignoring file IDs: ${[...ignore]}`);
   }
 
+  let replace: ArgonOpts['replace'] = defaults.replace;
+  if ('replace' in body) {
+    replace = Boolean(body.replace);
+  }
+  if (replace) {
+    warn('Insertion Mode: replace');
+  } else {
+    info('Insertion Mode: append');
+  }
+
   let email: ArgonOpts['email'];
   if (
     'email' in body &&
@@ -251,6 +265,7 @@ export async function parseBody(body: ParsedJSON): Promise<ArgonOpts> {
     projectId,
     single,
     ignore,
+    replace,
     email,
   };
 }

src/index.ts

@@ -119,29 +119,34 @@ export const argon: HttpFunction = async (req, res) => {
     const tableName = buildValidBQName(reportName);
     info(`Checking for existence of Table ${tableName}.`);
     const table = dataset.table(tableName);
-    const [tableExists] = await table.exists();
-    let tableSchema;
+    let [tableExists] = await table.exists();
+    let tableSchema = null;
     if (tableExists) {
-      info('Fetching BQ table schema for verification.');
-      const [metadata] = await table.getMetadata();
-      tableSchema = metadata.schema;
-      info(`BigQuery table fields: ${getNames(tableSchema)}`);
+      if (opts.replace) {
+        warn('Deleting existing Table for replacement.');
+        await table.delete();
+        tableExists = false;
+      } else {
+        info('Fetching existing Table Schema for verification.');
+        const [metadata] = await table.getMetadata();
+        tableSchema = metadata.schema;
+        info(`BigQuery Table fields: ${getNames(tableSchema)}`);
+      }
     } else {
-      tableSchema = null;
-      warn('Table does not already exist.');
+      info('Table does not exist.');
     }
 
-    info('Checking ingested files.');
     const ignoredIds = new Set(opts.ignore);
     const ingestedIds = new Set<number>();
     if (tableExists) {
+      info('Checking ingested files in BigQuery.');
       const path = `${opts.projectId}.${opts.datasetName}.${tableName}`;
       const query = buildLookbackQuery(path);
       const [rows] = await bq.query(query);
       rows.forEach(row => ingestedIds.add(Number(row[FILE_ID_COLUMN])));
     }
 
-    info('Enumerating report files.');
+    info('Fetching report files from API.');
     const reports = await reportFetcher.getReports();
     if (reports.size === 0) {
       throw Error('No report files found.');

src/typings.d.ts

@@ -42,6 +42,7 @@ export interface ArgonOpts {
   projectId: string;
   single: boolean;
   ignore: number[];
+  replace: boolean;
   email: string | null;
 }