ChatGPT Automatic Code Review in Gitlab MR

Automate code review directly within your GitLab Merge Requests using this n8n workflow. This powerful automation connects GitLab webhooks with OpenAI's advanced language models to provide instant, AI-driven feedback on code changes. When a new merge request is opened or updated in GitLab, a webhook triggers the workflow, which then fetches the code changes. These changes are sent to OpenAI's chat model, which analyzes the code and generates review comments. These AI-generated comments are then automatically posted back as discussions within the GitLab merge request, streamlining the review process and ensuring consistent code quality. This workflow is ideal for development teams looking to accelerate their code review cycles, catch potential issues earlier, and free up developer time for more complex tasks, ultimately reducing development costs and improving overall software quality.
14 nodeswebhook trigger260 views0 copiesOther
OpenAI

Workflow JSON

{"nodes": [{"name": "Sticky Note", "type": "n8n-nodes-base.stickyNote", "position": [880, 540], "parameters": {"content": "## Edit your own prompt \u2b07\ufe0f\n"}, "typeVersion": 1}, {"name": "Sticky Note2", "type": "n8n-nodes-base.stickyNote", "position": [-380, 580], "parameters": {"content": "## Filter comments and customize your trigger words \u2b07\ufe0f"}, "typeVersion": 1}, {"name": "Sticky Note3", "type": "n8n-nodes-base.stickyNote", "position": [-120, 560], "parameters": {"content": "## Replace your gitlab URL and token \u2b07\ufe0f"}, "typeVersion": 1}, {"name": "Webhook", "type": "n8n-nodes-base.webhook", "position": [-540, 760], "webhookId": "6cfd2f23-6f45-47d4-9fe0-8f6f1c05829a", "parameters": {"path": "e21095c0-1876-4cd9-9e92-a2eac737f03e", "options": {}, "httpMethod": "POST"}, "typeVersion": 1.1}, {"name": "Code", "type": "n8n-nodes-base.code", "position": [720, 540], "parameters": {"mode": "runOnceForEachItem", "jsCode": "// Loop over input items and add a new field called 'myNewField' to the JSON of each one\nvar diff = $input.item.json.gitDiff\n\nlet lines = diff.trimEnd().split('\\n');\n\nlet originalCode = '';\nlet newCode = '';\n\nlines.forEach(line => {\n console.log(line)\n if (line.startsWith('-')) {\n originalCode += line + \"\\n\";\n } else if (line.startsWith('+')) {\n newCode += line + \"\\n\";\n } else {\n originalCode += line + \"\\n\";\n newCode += line + \"\\n\";\n }\n});\n\nreturn {\n originalCode:originalCode,\n newCode:newCode\n};\n\n"}, "typeVersion": 2}, {"name": "Split Out1", "type": "n8n-nodes-base.splitOut", "position": [140, 740], "parameters": {"options": {}, "fieldToSplitOut": "changes"}, "typeVersion": 1}, {"name": "OpenAI Chat Model1", "type": "@n8n/n8n-nodes-langchain.lmChatOpenAi", "position": [900, 860], "parameters": {"options": {"baseURL": ""}}, "typeVersion": 1}, {"name": "Get Changes1", "type": "n8n-nodes-base.httpRequest", "position": [-60, 740], "parameters": {"url": "=https://gitlab.com/api/v4/projects/{{ $json[\"body\"][\"project_id\"] }}/merge_requests/{{ $json[\"body\"][\"merge_request\"][\"iid\"] }}/changes", "options": {}, "sendHeaders": true, "headerParameters": {"parameters": [{"name": "PRIVATE-TOKEN"}]}}, "typeVersion": 4.1}, {"name": "Skip File Change1", "type": "n8n-nodes-base.if", "position": [340, 740], "parameters": {"options": {}, "conditions": {"options": {"leftValue": "", "caseSensitive": true, "typeValidation": "strict"}, "combinator": "and", "conditions": [{"operator": {"type": "boolean", "operation": "false", "singleValue": true}, "leftValue": "={{ $json.renamed_file }}", "rightValue": ""}, {"operator": {"type": "boolean", "operation": "false", "singleValue": true}, "leftValue": "={{ $json.deleted_file }}", "rightValue": ""}, {"operator": {"type": "string", "operation": "startsWith"}, "leftValue": "={{ $json.diff }}", "rightValue": "@@"}]}}, "typeVersion": 2}, {"name": "Parse Last Diff Line1", "type": "n8n-nodes-base.code", "position": [540, 540], "parameters": {"mode": "runOnceForEachItem", "jsCode": "const parseLastDiff = (gitDiff) => {\n gitDiff = gitDiff.replace(/\\n\\\\ No newline at end of file/, '')\n \n const diffList = gitDiff.trimEnd().split('\\n').reverse();\n const lastLineFirstChar = diffList?.[0]?.[0];\n const lastDiff =\n diffList.find((item) => {\n return /^@@ \\-\\d+,\\d+ \\+\\d+,\\d+ @@/g.test(item);\n }) || '';\n\n const [lastOldLineCount, lastNewLineCount] = lastDiff\n .replace(/@@ \\-(\\d+),(\\d+) \\+(\\d+),(\\d+) @@.*/g, ($0, $1, $2, $3, $4) => {\n return `${+$1 + +$2},${+$3 + +$4}`;\n })\n .split(',');\n \n if (!/^\\d+$/.test(lastOldLineCount) || !/^\\d+$/.test(lastNewLineCount)) {\n return {\n lastOldLine: -1,\n lastNewLine: -1,\n gitDiff,\n };\n }\n\n\n const lastOldLine = lastLineFirstChar === '+' ? null : (parseInt(lastOldLineCount) || 0) - 1;\n const lastNewLine = lastLineFirstChar === '-' ? null : (parseInt(lastNewLineCount) || 0) - 1;\n\n return {\n lastOldLine,\n lastNewLine,\n gitDiff,\n };\n};\n\nreturn parseLastDiff($input.item.json.diff)\n"}, "typeVersion": 2}, {"name": "Post Discussions1", "type": "n8n-nodes-base.httpRequest", "position": [1280, 720], "parameters": {"url": "=https://gitlab.com/api/v4/projects/{{ $('Webhook').item.json[\"body\"][\"project_id\"] }}/merge_requests/{{ $('Webhook').item.json[\"body\"][\"merge_request\"][\"iid\"] }}/discussions", "method": "POST", "options": {}, "sendBody": true, "contentType": "multipart-form-data", "sendHeaders": true, "bodyParameters": {"parameters": [{"name": "body", "value": "={{ $('Basic LLM Chain1').item.json[\"text\"] }}"}, {"name": "position[position_type]", "value": "text"}, {"name": "position[old_path]", "value": "={{ $('Split Out1').item.json.old_path }}"}, {"name": "position[new_path]", "value": "={{ $('Split Out1').item.json.new_path }}"}, {"name": "position[start_sha]", "value": "={{ $('Get Changes1').item.json.diff_refs.start_sha }}"}, {"name": "position[head_sha]", "value": "={{ $('Get Changes1').item.json.diff_refs.head_sha }}"}, {"name": "position[base_sha]", "value": "={{ $('Get Changes1').item.json.diff_refs.base_sha }}"}, {"name": "position[new_line]", "value": "={{ $('Parse Last Diff Line1').item.json.lastNewLine || '' }}"}, {"name": "position[old_line]", "value": "={{ $('Parse Last Diff Line1').item.json.lastOldLine || '' }}"}]}, "headerParameters": {"parameters": [{"name": "PRIVATE-TOKEN"}]}}, "typeVersion": 4.1}, {"name": "Need Review1", "type": "n8n-nodes-base.if", "position": [-320, 760], "parameters": {"options": {}, "conditions": {"options": {"leftValue": "", "caseSensitive": true, "typeValidation": "strict"}, "combinator": "and", "conditions": [{"operator": {"name": "filter.operator.equals", "type": "string", "operation": "equals"}, "leftValue": "={{ $json.body.object_attributes.note }}", "rightValue": "+0"}]}}, "typeVersion": 2}, {"name": "Basic LLM Chain1", "type": "@n8n/n8n-nodes-langchain.chainLlm", "position": [880, 720], "parameters": {"prompt": "=File path\uff1a{{ $('Skip File Change1').item.json.new_path }}\n\n```Original code\n {{ $json.originalCode }}\n```\nchange to\n```New code\n {{ $json.newCode }}\n```\nPlease review the code changes in this section:", "messages": {"messageValues": [{"message": "# Overview:\n You are a senior programming expert Bot, responsible for reviewing code changes and providing review recommendations.\n At the beginning of the suggestion, it is necessary to clearly make a decision to \"reject\" or \"accept\" the code change, and rate the change in the format \"Change Score: Actual Score\", with a score range of 0-100 points.\n Then, point out the existing problems in concise language and a stern tone.\n If you feel it is necessary, you can directly provide the modified content.\n Your review proposal must use rigorous Markdown format."}]}}, "typeVersion": 1.2}, {"name": "Sticky Note4", "type": "n8n-nodes-base.stickyNote", "position": [1200, 540], "parameters": {"content": "## Replace your gitlab URL and token \u2b07\ufe0f"}, "typeVersion": 1}], "pinData": {}, "connections": {"Code": {"main": [[{"node": "Basic LLM Chain1", "type": "main", "index": 0}]]}, "Webhook": {"main": [[{"node": "Need Review1", "type": "main", "index": 0}]]}, "Split Out1": {"main": [[{"node": "Skip File Change1", "type": "main", "index": 0}]]}, "Get Changes1": {"main": [[{"node": "Split Out1", "type": "main", "index": 0}]]}, "Need Review1": {"main": [[{"node": "Get Changes1", "type": "main", "index": 0}]]}, "Basic LLM Chain1": {"main": [[{"node": "Post Discussions1", "type": "main", "index": 0}]]}, "Skip File Change1": {"main": [[{"node": "Parse Last Diff Line1", "type": "main", "index": 0}]]}, "OpenAI Chat Model1": {"ai_languageModel": [[{"node": "Basic LLM Chain1", "type": "ai_languageModel", "index": 0}]]}, "Parse Last Diff Line1": {"main": [[{"node": "Code", "type": "main", "index": 0}]]}}}

How to Import This Workflow

  1. 1Copy the workflow JSON above using the Copy Workflow JSON button.
  2. 2Open your n8n instance and go to Workflows.
  3. 3Click Import from JSON and paste the copied workflow.

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