ekuiper-new/docs/en_US/guide/sinks/builtin/file.md

File Sink

The sink saves the analysis result to a specified file. The file source is the opposite connector that can read the file sink’s output.

Properties

Property name	Optional	Description
path	false	The file path for saving the result, such as /tmp/result.txt
interval	true	The time interval (ms) for flushing the analysis result into the file. The default value is 1000, which means write the analysis result with every one second.
fileType	true	The type of the file, could be json, csv or lines. Default value is lines. Please check file types for detail.
hasHeader	true	Whether to produce the header line. Currently, it is only effective for csv file type.
delimiter	true	The delimiter character, usually apply for the header. Only effective for csv file type.

Other common sink properties are supported. Please refer to the sink common properties for more information. Among them, the format property is used to define the format of the data in the file. Some file types can only work with specific format. Please check file types for detail.

File Types

The file sink can write data into different file types, such as:

• lines: This is the default type. It writes line-separated files that can be decoded by the format parameter in the stream definition. For example, to write line-separated JSON strings, set the file type to lines and the format to json.
• json: This type writes standard JSON array format files. For an example, see here. To use this file type, set the format to json.
• csv: This type writes comma-separated csv files. You can also use custom separators. To use this file type, set the format to delimited.

Sample usage

Below is a sample for selecting temperature greater than 50 degree, and save the result into file /tmp/result.txt with every 5 seconds.

{
  "sql": "SELECT * from demo where temperature>50",
  "actions": [
    {
      "file": {
        "path": "/tmp/result.txt",
        "interval": 5000,
        "fileType": "lines",
        "format": "json"
      }
    }
  ]
}