Script Development / Built-in Variables

To facilitate scripts in obtaining information about their runtime status, DataFlux Func directly embeds some variables in the script context that can be used directly.

Built-in Variable	Type	Applicable Scope	Description	Example Value
_DFF_IMAGE_INFO	dict	All	Current image information	See below
_DFF_TRACE_ID	str	All	Trace ID Internal Trace within Func	"TRACE-14E6D8D6-1F1A-4A5A-8280-854F6DD8CDB0"
_DFF_TASK_ID	str	All	Task ID	"task-2UHeFYPdb6Q7"
_DFF_ROOT_TASK_ID	str	All	Main Task ID For the main task itself, fixed as "ROOT	"task-2UHeFYPdb6Q7"
_DFF_SCRIPT_SET_ID	str	All	Script Set ID	"demo"
_DFF_SCRIPT_SET_NAME	str	All	Script Set Name Same as _DFF_SCRIPT_SET_ID	"demo"
_DFF_SCRIPT_SET_TITLE	str	All	Script Set Title	"Example"
_DFF_SCRIPT_ID	str	All	Script ID	"demo__basic"
_DFF_SCRIPT_NAME	str	All	Script Name The part without the Script Set ID	"basic"
_DFF_SCRIPT_TITLE	str	All	Script Title	"Basics"
_DFF_FUNC_ID	str	All	Function ID	"demo__basic.hello_world"
_DFF_FUNC_NAME	str	All	Function Name The part without the Script ID	"hello_world"
_DFF_FUNC_TITLE	str	All	Function Title	"My Function"
_DFF_FUNC_CHAIN	list	All	Function Call Chain	[ "demo__basic.run", "demo__basic.hello_world" ]
_DFF_FUNC_CALL_KWARGS	dict	All	Function Call Arguments	{"x": 1, "y": 2}
_DFF_ORIGIN	str	All	Task Source	"funcAPI"
_DFF_ORIGIN_ID	str	All	Source ID	"fapi-tDGC12Gdc5H6"
_DFF_TRIGGER_TIME	int	All	Scheduled Start Time (seconds)	1625651909
_DFF_TRIGGER_TIME_MS	int	All	Scheduled Start Time (milliseconds)	1625651909582
_DFF_START_TIME	int	All	Actual Start Time (seconds)	1625651910
_DFF_START_TIME_MS	int	All	Actual Start Time (milliseconds)	1625651910630
_DFF_QUEUE	int	All	Execution Queue	2
_DFF_CRON_EXPR	str	Scheduled Tasks	Crontab Expression	* * * * *
_DFF_HTTP_REQUEST	dict	Function API Function Page	Request body when the interface is called	See below

Difference Between _DFF_TRIGGER_TIME and _DFF_START_TIME

_DFF_START_TIME refers to the actual start time of the function, equivalent to int(time.time()) executed at the function entry point, which may be delayed due to factors like queue congestion.

_DFF_TRIGGER_TIME, on the other hand, refers to the function trigger time, which does not change due to queue congestion and can be considered as the "scheduled start time". Its value is determined as follows:

Function Call Method	Value
UI Execution	The time when the backend API service receives the HTTP request
Function API	The time when the backend API service receives the HTTP request
Scheduled Tasks	The exact time corresponding to the Crontab expression

When using 'Scheduled Tasks' to obtain time series data at fixed intervals, you should use _DFF_TRIGGER_TIME and _DFF_TRIGGER_TIME_MS as the benchmark, do not use time.time() in your code to get the current time

_DFF_IMAGE_INFO Data Structure

_DFF_IMAGE_INFO contains DataFlux Func image information, including version number, etc.

Field	Description
EDITION	Edition, values are "original", "GSE", "TSE"
VERSION	Version number, e.g., "1.2.3"
ARCHITECTURE	Architecture, values are "x86_64", "aarch64"
RELEASE_TIMESTAMP	Release time (UNIX timestamp, seconds)

{
  "EDITION"          : "GSE",
  "VERSION"          : "7.3.6",
  "ARCHITECTURE"     : "x86_64",
  "RELEASE_TIMESTAMP": 1761298748
}

_DFF_HTTP_REQUEST Data Structure

_DFF_HTTP_REQUEST contains the request body details.

Given the following request:

curl \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"a":"b"}' \
    http://localhost:8088/api/v1/al/func-api-xxxxx/s?x=y

Then, the value of _DFF_HTTP_REQUEST is as follows:

{
    "method"     : "POST",
    "originalUrl": "/api/v1/al/func-api-xxxxx/s?x=y",
    "url"        : "/api/v1/al/func-api-xxxxx/s",
    "host"       : "localhost:8088",
    "hostname"   : "localhost",
    "protocol"   : "http",
    "headers": {
        "host"          : "localhost:8088",
        "user-agent"    : "curl/7.68.0",
        "accept"        : "*/*",
        "content-type"  : "application/json",
        "content-length": "9"
    },
    "query": {
        "x": "y"
    },
    "body": {
        "a": "b"
    },
    "ip" : "127.0.0.1",
    "ips": [],
    "xhr": false
}

The fields included in _DFF_HTTP_REQUEST may vary slightly across different versions of DataFlux Func. Please refer to the actual content

The headers field is of type IgnoreCaseDict. IgnoreCaseDict inherits from dict and is used similarly but is case-insensitive for key names. For example, the following lines of code will all retrieve the same value

_DFF_HTTP_REQUEST['headers']['user-agent']
_DFF_HTTP_REQUEST['headers']['User-Agent']
_DFF_HTTP_REQUEST['headers']['USER-AGENT']