{ "name": "Silent failure check: green runs that did nothing", "nodes": [ { "parameters": { "rule": { "interval": [ { "field": "hours", "hoursInterval": 1 } ] } }, "id": "c2b0d1e2-0002-4a10-9c01-000000000001", "name": "Every Hour", "type": "n8n-nodes-base.scheduleTrigger", "typeVersion": 1.2, "position": [ -540, 0 ] }, { "parameters": { "jsCode": "// Configure the check here. One entry per workflow you actually care about.\n//\n// workflowId the id in the /workflow/ URL\n// label what to call it in the alert\n// minRuns how many successful runs you expect in the window below\n// windowHours how far back to look\n// floorMs a run faster than this almost certainly processed nothing\n//\n// floorMs is the whole trick. A workflow that fetches rows, loops and writes\n// cannot finish in 400ms. When it does, an upstream filter returned zero items\n// and every node after it was skipped, which n8n records as a success.\n\nreturn [{\n json: {\n n8nBaseUrl: 'https://n8n.example.com',\n checks: [\n { workflowId: 'REPLACE_ME', label: 'Lead routing', minRuns: 4, windowHours: 1, floorMs: 800 },\n { workflowId: 'REPLACE_ME_TOO', label: 'Nightly invoice sync', minRuns: 1, windowHours: 24, floorMs: 2000 }\n ]\n }\n}];" }, "id": "c2b0d1e2-0002-4a10-9c01-000000000002", "name": "Checks To Run", "type": "n8n-nodes-base.code", "typeVersion": 2, "position": [ -320, 0 ] }, { "parameters": { "fieldToSplitOut": "checks", "include": "selectedOtherFields", "fieldsToInclude": "n8nBaseUrl", "options": {} }, "id": "c2b0d1e2-0002-4a10-9c01-000000000003", "name": "One Item Per Check", "type": "n8n-nodes-base.splitOut", "typeVersion": 1, "position": [ -100, 0 ] }, { "parameters": { "url": "={{ $json.n8nBaseUrl }}/api/v1/executions", "sendQuery": true, "queryParameters": { "parameters": [ { "name": "workflowId", "value": "={{ $json.workflowId }}" }, { "name": "status", "value": "success" }, { "name": "limit", "value": "100" } ] }, "sendHeaders": true, "headerParameters": { "parameters": [ { "name": "X-N8N-API-KEY", "value": "={{ $env.N8N_API_KEY }}" }, { "name": "accept", "value": "application/json" } ] }, "options": { "response": { "response": { "neverError": true, "fullResponse": true } } } }, "id": "c2b0d1e2-0002-4a10-9c01-000000000004", "name": "List Successful Runs", "type": "n8n-nodes-base.httpRequest", "typeVersion": 4.2, "position": [ 120, 0 ], "onError": "continueRegularOutput" }, { "parameters": { "jsCode": "// Emit ONE item per problem. When everything is healthy this returns nothing,\n// the Slack node never runs, and you get no message. Silence means silence.\n\nconst problems = [];\n\nfor (let i = 0; i < items.length; i++) {\n const res = items[i].json;\n const check = $('One Item Per Check').all()[i].json;\n const label = check.label || check.workflowId;\n\n if (res.statusCode && res.statusCode >= 400) {\n problems.push({\n json: {\n label,\n kind: 'api-unreachable',\n detail: 'The n8n API answered ' + res.statusCode + '. Check N8N_API_KEY and that the public API is enabled.'\n }\n });\n continue;\n }\n\n const body = res.body || res;\n const runs = Array.isArray(body.data) ? body.data : [];\n const cutoff = Date.now() - (check.windowHours * 60 * 60 * 1000);\n\n const recent = runs.filter(r => new Date(r.startedAt).getTime() >= cutoff);\n\n // Case 1: the trigger itself stopped firing. No executions at all is the\n // failure people notice last, because there is no red anywhere to see.\n if (recent.length < check.minRuns) {\n problems.push({\n json: {\n label,\n kind: 'not-running',\n detail: 'Expected at least ' + check.minRuns + ' successful run(s) in the last ' +\n check.windowHours + 'h, found ' + recent.length + '. The trigger may be off, ' +\n 'the workflow deactivated, or the schedule never fired.'\n }\n });\n }\n\n // Case 2: it ran, it went green, and it finished too fast to have done work.\n const durations = recent\n .filter(r => r.stoppedAt)\n .map(r => ({ id: r.id, ms: new Date(r.stoppedAt) - new Date(r.startedAt) }));\n\n const tooFast = durations.filter(d => d.ms < check.floorMs);\n\n if (tooFast.length > 0) {\n const sorted = durations.map(d => d.ms).sort((a, b) => a - b);\n const median = sorted.length ? sorted[Math.floor(sorted.length / 2)] : 0;\n problems.push({\n json: {\n label,\n kind: 'ran-but-empty',\n detail: tooFast.length + ' of ' + recent.length + ' successful runs finished under ' +\n check.floorMs + 'ms (median ' + median + 'ms). Green, and almost certainly ' +\n 'processing zero items. Executions: ' + tooFast.slice(0, 5).map(d => d.id).join(', ')\n }\n });\n }\n}\n\nreturn problems;" }, "id": "c2b0d1e2-0002-4a10-9c01-000000000005", "name": "Find Silent Failures", "type": "n8n-nodes-base.code", "typeVersion": 2, "position": [ 340, 0 ] }, { "parameters": { "method": "POST", "url": "https://hooks.slack.com/services/REPLACE/WITH/YOUR_WEBHOOK", "sendBody": true, "specifyBody": "json", "jsonBody": "={{ JSON.stringify({ text: ':mag: Silent failure: ' + $json.label, blocks: [ { type: 'section', text: { type: 'mrkdwn', text: '*' + $json.label + '* (' + $json.kind + ')\\n' + $json.detail } } ] }) }}", "options": { "response": { "response": { "neverError": true } } } }, "id": "c2b0d1e2-0002-4a10-9c01-000000000006", "name": "Alert Slack", "type": "n8n-nodes-base.httpRequest", "typeVersion": 4.2, "position": [ 560, 0 ], "onError": "continueRegularOutput" } ], "connections": { "Every Hour": { "main": [ [ { "node": "Checks To Run", "type": "main", "index": 0 } ] ] }, "Checks To Run": { "main": [ [ { "node": "One Item Per Check", "type": "main", "index": 0 } ] ] }, "One Item Per Check": { "main": [ [ { "node": "List Successful Runs", "type": "main", "index": 0 } ] ] }, "List Successful Runs": { "main": [ [ { "node": "Find Silent Failures", "type": "main", "index": 0 } ] ] }, "Find Silent Failures": { "main": [ [ { "node": "Alert Slack", "type": "main", "index": 0 } ] ] } }, "settings": { "executionOrder": "v1" }, "pinData": {}, "meta": { "instanceId": "shared-template" } }