Terraform updates

Attempting to do some log parsing into cloudwatch logs

terraform/lambda/src/cloudwatch-logs.js

@@ -0,0 +1,88 @@
+const { CloudWatchLogs } = require('aws-sdk');
+
+// Split up ARN like "arn:aws:logs:eu-west-1:123456789012:log-group:example-group:*"
+const [,,, region,,, logGroupName] = process.env.CLOUDWATCH_LOGS_GROUP_ARN.split(':');
+
+const cloudwatchlogs = new CloudWatchLogs({ region });
+
+
+// Group array of hashes by defined key.
+//
+const groupBy = (array, key) => (
+  array.reduce((object, item) => {
+    const result = object;
+
+    if (result[item[key]]) {
+      result[item[key]].push(item);
+    } else if (item[key]) {
+      result[item[key]] = [item];
+    }
+    return result;
+  }, {})
+);
+
+// Find log stream by prefix.
+//
+const findLogStream = async (logStreamNamePrefix) => {
+  const params = { logGroupName, logStreamNamePrefix };
+
+  const { logStreams } = await cloudwatchlogs.describeLogStreams(params).promise();
+
+  if (logStreams.length > 1) {
+    throw new Error(`Found '${logStreams.length}' matching CloudWatch Logs streams but expected only one.`);
+  }
+
+  return logStreams[0];
+};
+
+// Get log stream or creting it if not present yet.
+//
+// Name format:
+//   2000-01-01
+//
+const describeLogStream = async (logStreamName) => {
+  let logStream = await findLogStream(logStreamName);
+
+  if (!logStream) {
+    await cloudwatchlogs.createLogStream({ logGroupName, logStreamName }).promise();
+    logStream = await findLogStream(logStreamName);
+  }
+
+  return logStream;
+};
+
+// Extend the original record with some additional fields
+// and encapsule records into CloudWatch Logs event.
+//
+const buildlogEvents = records => (
+  records.map((record) => {
+    const payload = record;
+    payload.name = 'logs:cloudfront';
+
+    return {
+      message: JSON.stringify(payload),
+      timestamp: new Date(`${payload.date} ${payload.time} UTC`).getTime(),
+    };
+  }).sort((a, b) => a.timestamp - b.timestamp) // Events in a request must be chronological ordered
+);
+
+// Send the given documents to CloudWatch Logs group.
+//
+exports.putLogEvents = async (records) => {
+  const groupedRecords = groupBy(records, 'date');
+
+  const putLogEventsCalls = Object.keys(groupedRecords).map(async (key) => {
+    const logStream = await describeLogStream(key);
+
+    const params = {
+      logEvents: buildlogEvents(groupedRecords[key]),
+      logGroupName,
+      logStreamName: logStream.logStreamName,
+      sequenceToken: logStream.uploadSequenceToken,
+    };
+
+    return cloudwatchlogs.putLogEvents(params).promise();
+  });
+
+  return Promise.all(putLogEventsCalls);
+};