Create healthcheck.js

healthcheck.js

@@ -0,0 +1,72 @@
+const fetch = (...args) => import('node-fetch').then(({ default: fetch }) => fetch(...args));
+
+const URL = 'http://flosight.duckdns.org';
+
+const checks = [];
+
+//Check if UI is working and is type HTML
+checks.push(function check_UI() {
+    return new Promise((resolve, reject) => {
+        fetch(URL).then(res => {
+            if (!res.ok || res.status !== 200)
+                return resolve(`UI fetch failed with status ${res.status}`);
+            if (!res.headers.get('content-type').includes('text/html'))
+                return resolve(`UI fetch: content-type not HTML`);
+            //TODO: check DOM objects for UI
+            resolve(true);
+        }).catch(error => reject(error));
+    })
+});
+
+//Check if the Sync is finished and 100%
+checks.push(function check_API_sync() {
+    return new Promise((resolve, reject) => {
+        fetch(URL + '/api/sync').then(res => {
+            if (!res.ok || res.status !== 200)
+                return resolve(`Sync API fetch failed with status ${res.status}`);
+            res.json().then(data => {
+                if (data.error)
+                    return resolve(`Sync API error: ${data.error}`);
+                if (data.status !== "finished" || data.syncPercentage !== 100)
+                    return resolve(`Sync not finished: current percentage ${data.syncPercentage}`);
+                resolve(true);
+            }).catch(error => resolve(`Sync API: response not JSON`))
+        }).catch(error => reject(error));
+    })
+});
+
+//Check if the last synced block time is not too old
+checks.push(function check_lastBlockTime() {
+    const ALLOW_BLOCK_DELAY = 60 * 60 * 1000; //1hr
+    return new Promise((resolve, reject) => {
+        fetch(URL + "/api/blocks?limit=1").then(res => {
+            if (!res.ok || res.status !== 200)
+                return resolve(`Last Block fetch with status ${res.status}`);
+            res.json().then(data => {
+                if (!data.blocks.length)
+                    return resolve(`Last Block not found`);
+                let last_block_no = data.blocks[0].height, last_block_time = data.blocks[0].time;
+                last_block_time = last_block_time * 1000; //sec to ms
+                if (last_block_time + ALLOW_BLOCK_DELAY < Date.now())
+                    return resolve(`Last Block#${last_block_no} synced at ${last_block_time}`);
+                resolve(true);
+            }).catch(error => resolve(`Last Block API: response not JSON`))
+        }).catch(error => reject(error))
+    })
+})
+
+Promise.all(checks.map(c => c())).then(results => {
+    let reasons = results.filter(r => r !== true);
+    if (!reasons.length) {
+        console.debug("HEALTHY");
+        process.exit(0);
+    } else {
+        console.debug("UNHEALTHY");
+        console.debug(reasons);
+        process.exit(1);
+    }
+}).catch(error => {
+    console.debug("ERROR");
+    console.error(error);
+    process.exit(1);
+})