start.json

{
    "run": [
        {
            "method": "input",
            "params": {
                "title": "Setup",
                "form": [
                    {
                        "key": "create_venv",
                        "title": "Create virtualenv",
                        "description": "Command to create virtualenv",
                        "default": "python -m venv .langflow_venv"
                    },
                    {
                        "key": "activate_command",
                        "title": "Activate virtualenv",
                        "description": "Command to activate virtualenv",
                        "default": "{{os.platform() === 'win32' ? '.langflow_venv\\\\Scripts\\\\activate' : 'source .langflow_venv/bin/activate'}}"
                    }
                ]
            }
        },
        {
            "method": "self.set",
            "params": {
                "config.json": {
                  "create_venv": "{{input.create_venv}}",
                  "activate_command": "{{input.activate_command}}"
                }
            }
        },
        {
            "method": "shell.start"
        },
        {
            "method": "shell.enter",
            "params": {
                "message": "{{self.config.create_venv}}",
                "on": [{
                    "event": null,
                    "return": true
                }]
            }
        },
        {
            "method": "shell.enter",
            "params": {
                "message": "{{self.config.activate_command}}",
                "on": [{
                    "event": null,
                    "return": true
                }]
            }
        },
        {
            "method": "shell.enter",
            "params": {
                "message": "python -m pip install langflow -U",
                "on": [{
                  "event": null,
                  "return": true
                }]
            }
        },
        {
            "method": "shell.enter",
            "params": {
                "message": "python -m langflow",
                "on": [{
                    "event": "/Access (http[0-9\/.:]+)/",
                    "return": "{{event.matches[0][1]}}"
                }]
            }
        },
        {
            "method": "browser.open",
            "params": {
                "uri": "{{input}}",
                "target": "_blank"
            }
        },
        {
            "method": "process.wait"
        }
    ]
}