chore: move code from internal repo (#11)

Moving code as-is from the current internal repo. The repo was updated few minutes ago, so it should be the latest code version.

The code was not edited, but there was some re-formatting happening, probably due to a different prettier settings. I have copied prettier params from our package as well, but it does not seem working...

Author: voho

API.md

@@ -0,0 +1,66 @@
+// Ignoring some checks since the function is in pure JS
+
+/* eslint-disable */
+const aws = require('aws-sdk');
+
+const DOCS = `
+          ## Display a CloudWatch bitmap graph
+          Displays CloudWatch metrics as a bitmap, for faster display of metrics.
+          
+          ### Widget parameters
+          Param | Description
+          ---|---
+          **graph** | The graph definition. Use the parameters from the **Source** tab in CloudWatch Console's **Metrics** page.
+          **useMonitorPortal** (default = true) | Flag indicating whether we want to use MonitorPortal to render the graph. False will switch to CloudWatch API.
+          
+          ### Example parameters
+          \`\`\` yaml
+          useMonitorPortal: boolean
+          graph:
+            view: timeSeries
+            metrics:
+            - [ AWS/Lambda, Invocations ]
+            region: ${process.env.AWS_REGION}
+          \`\`\`
+          `;
+
+exports.handler = async (event: any) => {
+    async function renderUsingCloudWatch(graph: any, width: number, height: number) {
+        const params = {MetricWidget: JSON.stringify(graph)};
+        const region = graph.region;
+        const customBackoff = (retryCount: number) => {
+            // Keep retrying with a random delay, long enough to overcome throttling from CW
+            const delay = 300 + Math.floor(Math.random() * 500);
+            console.log(`retry number ${retryCount} with a delay of ${delay} ms`);
+            return delay;
+        }
+        const clientOptions = {
+            region,
+            // Keep retrying until the Lambda times out
+            maxRetries: 99,
+            retryDelayOptions: {customBackoff},
+            httpOptions: {
+                connectTimeout: 3 * 1000,
+                timeout: 3 * 1000,
+            },
+        };
+        const cloudwatch = new aws.CloudWatch(clientOptions);
+        const image = await cloudwatch.getMetricWidgetImage(params).promise();
+        const base64Image = Buffer.from(image.MetricWidgetImage).toString('base64');
+        return `<img width="${width}" height="${height}" loading="lazy" src="data:image/png;base64,${base64Image}"/>`;
+    }
+
+    if (event.describe) {
+        return DOCS;
+    }
+
+    const widgetContext = event.widgetContext;
+    const timeRange = widgetContext.timeRange.zoom || widgetContext.timeRange;
+    const start = new Date(timeRange.start).toISOString();
+    const end = new Date(timeRange.end).toISOString();
+    const width = widgetContext.width;
+    const height = widgetContext.height;
+    const graph = Object.assign(event.graph, {start, end, width, height});
+
+    return renderUsingCloudWatch(graph, width, height);
+};

assets/BitmapWidgetRenderingSupport/index.ts

@@ -0,0 +1,82 @@
+import aws = require("aws-sdk");
+
+const region = process.env.AWS_REGION;
+const millisPerDay = 1000 * 60 * 60 * 24;
+
+const clientOptions = {
+    region,
+    maxRetries: 5,
+    httpOptions: {
+        connectTimeout: 3 * 1000,
+        timeout: 3 * 1000,
+    },
+};
+
+const cloudwatch = new aws.CloudWatch(clientOptions);
+const sm = new aws.SecretsManager(clientOptions);
+
+function daysSince(date: any, now = Date.now()) {
+    const millis = now - date.getTime();
+    const days = millis / millisPerDay;
+    return Math.floor(days);
+}
+
+exports.handler = async (event: any, context: any) => {
+    console.debug("event:", JSON.stringify(event));
+    console.debug("context:", JSON.stringify(context));
+
+    console.info(`retrieving secret: ${event.secretId}`);
+    const secret = await sm
+        .describeSecret({
+            SecretId: event.secretId,
+        })
+        .promise();
+
+    console.debug("found secret: ", JSON.stringify(secret));
+    if (!secret.Name || !secret.CreatedDate) {
+        throw new Error("invalid secret response");
+    }
+
+    // use retrieved secret name in case secretId was an arn
+    const secretName = secret.Name;
+    const lastChangedDate = secret.LastChangedDate ?? secret.CreatedDate;
+    const lastRotatedDate = secret.LastRotatedDate ?? secret.CreatedDate;
+    const now = Date.now();
+
+    const metricData = [
+        {
+            MetricName: "DaysSinceLastChange",
+            Dimensions: [
+                {
+                    Name: "SecretName",
+                    Value: secretName,
+                },
+            ],
+            Unit: "Count",
+            Value: daysSince(lastChangedDate, now),
+        },
+        {
+            MetricName: "DaysSinceLastRotation",
+            Dimensions: [
+                {
+                    Name: "SecretName",
+                    Value: secretName,
+                },
+            ],
+            Unit: "Count",
+            Value: daysSince(lastRotatedDate, now),
+        },
+    ];
+
+    const params = {
+        Namespace: "SecretsManager",
+        MetricData: metricData,
+    };
+
+    console.debug("putMetricData params: ", JSON.stringify(params));
+
+    console.info(`publishing metrics for secret: ${event.secretId}`);
+    await cloudwatch.putMetricData(params).promise();
+
+    return Promise.resolve();
+};