adding query for headObject query

Author: barnettet31

src/queries/s3.js

@@ -193,3 +193,32 @@ export const pageObjectsFromS3 = ({
     .map(listObjects)
     .parallel(parallel);
 };
+
+export const headS3Object= ({
+  id: pipelineId,
+  debug = d('s3'),
+  bucketName = process.env.BUCKET_NAME,
+  headRequestField = 'headRequest',
+  headResponseField = 'headResponse',
+  parallel = Number(process.env.S3_PARALLEL) || Number(process.env.PARALLEL) || 8,
+  step = 'get',
+  ...opt
+} = {}) => {
+  const connector = new Connector({
+    pipelineId, debug, bucketName, ...opt,
+  });
+
+  const headObject = (uow) => {
+    if (!uow[headRequestField]) return _(Promise.resolve(uow));
+
+    const p = () => connector.headObject(uow[headRequestField], uow)
+      .then((headResponse) => ({ ...uow, [headResponseField]: headResponse }))
+      .catch(rejectWithFault(uow));
+
+    return _(uow.metrics?.w(p, step) || p()); // wrap promise in a stream
+  };
+
+  return (s) => s
+    .map(headObject)
+    .parallel(parallel);
+};

test/unit/queries/s3.test.js

@@ -12,6 +12,7 @@ import {
   toGetObjectRequest,
   toGetObjectRequest2,
   getObjectFromS3AsStream,
+  headS3Object,
 } from '../../../src/queries/s3';
 
 import Connector from '../../../src/connectors/s3';
@@ -329,6 +330,68 @@ describe('queries/s3.js', () => {
       })
       .done(done);
   });
+  it('should head object', (done) => {
+    const stub = sinon.stub(Connector.prototype, 'headObject').resolves({
+      Metadata: {
+        testkey: '1',
+      },
+    });
+
+    const uows = [{
+      headRequest: {
+        Key: 'k1',
+      },
+    }];
+
+    _(uows)
+      .through(headS3Object())
+      .collect()
+      .tap((collected) => {
+        console.log(JSON.stringify(collected, null, 2));
+
+        expect(stub).to.have.been.calledWith({
+          Key: 'k1',
+        });
+
+        expect(collected.length).to.equal(1);
+        expect(collected[0]).to.deep.equal({
+          headRequest: {
+            Key: 'k1',
+          },
+          headResponse: {
+            Metadata: {
+              testkey: '1',
+            },
+          },
+        });
+      })
+      .done(done);
+  });
+  it('should head object missing headRequestField', (done) => {
+    const stub = sinon.stub(Connector.prototype, 'headObject').resolves({
+      Metadata: {
+        testkey: '1',
+      },
+    });
+
+    const uows = [{
+      // headRequest: {
+      //   Key: 'k1',
+      // },
+    }];
+
+    _(uows)
+      .through(headS3Object())
+      .collect()
+      .tap((collected) => {
+        // console.log(JSON.stringify(collected, null, 2));
+
+        expect(collected[0]).to.deep.equal({});
+
+        expect(collected.length).to.equal(1);
+      })
+      .done(done);
+  });
 });
 
 const GET_RESPONSE = {