From d700a85c28c6520c5e382d637a5af4610c494674 Mon Sep 17 00:00:00 2001
From: Morgan McCauley <morgan@mccauley.co.nz>
Date: Thu, 20 Jul 2023 07:12:51 +1200
Subject: [PATCH] DPLT-1044 Create scheduled Lambda to write lag behind near
 social (#137)

---
 .../latest-post-metrics-writer.js             | 33 ----------
 indexer-js-queue-handler/serverless.yml       |  4 +-
 .../social-lag-metrics-writer.js              | 63 +++++++++++++++++++
 3 files changed, 65 insertions(+), 35 deletions(-)
 delete mode 100644 indexer-js-queue-handler/latest-post-metrics-writer.js
 create mode 100644 indexer-js-queue-handler/social-lag-metrics-writer.js

diff --git a/indexer-js-queue-handler/latest-post-metrics-writer.js b/indexer-js-queue-handler/latest-post-metrics-writer.js
deleted file mode 100644
index 95f03c8f9..000000000
--- a/indexer-js-queue-handler/latest-post-metrics-writer.js
+++ /dev/null
@@ -1,33 +0,0 @@
-import fetch from "node-fetch";
-import AWS from "aws-sdk";
-
-import Metrics from "./metrics.js";
-
-export const handler = async () => {
-    const metrics = new Metrics("QueryAPI");
-
-    const response = await fetch("https://api.near.social/index", {
-        method: "POST",
-        headers: {
-            "Content-Type": "application/json",
-        },
-        body: JSON.stringify({
-            action: "post",
-            key: "main",
-            options: {
-                limit: 1,
-                order: "desc",
-            },
-        }),
-    });
-
-    const body = await response.text();
-
-    if (response.status !== 200) {
-        throw new Error(body);
-    }
-
-    const [{ blockHeight }] = JSON.parse(body);
-
-    await metrics.putBlockHeight("social.near", "posts", blockHeight);
-};
diff --git a/indexer-js-queue-handler/serverless.yml b/indexer-js-queue-handler/serverless.yml
index a44657e3e..368400cc7 100644
--- a/indexer-js-queue-handler/serverless.yml
+++ b/indexer-js-queue-handler/serverless.yml
@@ -41,8 +41,8 @@ constructs:
       timeout: 15 # 1.5 minutes as lift multiplies this value by 6 (https://github.com/getlift/lift/blob/master/docs/queue.md#retry-delay)
 
 functions:
-  latestPostMetricsWriter:
-    handler: latest-post-metrics-writer.handler
+  socialLagMetricsWriter:
+    handler: social-lag-metrics-writer.handler
     events:
       - schedule: rate(1 minute)
 
diff --git a/indexer-js-queue-handler/social-lag-metrics-writer.js b/indexer-js-queue-handler/social-lag-metrics-writer.js
new file mode 100644
index 000000000..ec9d28f92
--- /dev/null
+++ b/indexer-js-queue-handler/social-lag-metrics-writer.js
@@ -0,0 +1,63 @@
+import fetch from "node-fetch";
+import AWS from "aws-sdk";
+
+import Metrics from "./metrics.js";
+
+const fetchJson = async (url, requestBody, requestHeaders) => {
+    const response = await fetch(url, {
+        method: "POST",
+        headers: {
+            "Content-Type": "application/json",
+            ...requestHeaders,
+        },
+        body: JSON.stringify(requestBody),
+    });
+
+    const responseBody = await response.json();
+
+    if (response.status !== 200 || responseBody.errors) {
+        throw new Error(JSON.stringify(responseBody));
+    }
+
+    return responseBody;
+};
+
+export const handler = async () => {
+    const metrics = new Metrics("QueryAPI");
+
+    const [nearSocialResponse, feedIndexerResponse] = await Promise.all([
+        fetchJson(`https://api.near.social/index`, {
+            action: "post",
+            key: "main",
+            options: {
+                limit: 1,
+                order: "desc",
+            },
+        }),
+        fetchJson(
+            `${process.env.HASURA_ENDPOINT}/v1/graphql`,
+            {
+                query: `{
+                    dataplatform_near_social_feed_posts(
+                        limit: 1,
+                        order_by: { block_height: desc }
+                    ) {
+                        block_height
+                    }
+                }`,
+            },
+            {
+                ["X-Hasura-Role"]: "dataplatform_near",
+            }
+        ),
+    ]);
+
+    const nearSocialBlockHeight = nearSocialResponse[0].blockHeight;
+    const feedIndexerBlockHeight =
+        feedIndexerResponse.data.dataplatform_near_social_feed_posts[0]
+            .block_height;
+
+    const lag = nearSocialBlockHeight - feedIndexerBlockHeight;
+
+    await metrics.putCustomMetric("dataplatform.near", "social_feed", false, 'SOCIAL_LAG', lag);
+};