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title: Built-in Time Variable sidebar_position: 7

1. General

Requirements Background

Users hope that when writing code, the time format requirements are ever-changing, and the existing Linkis custom variables is currently not enough to support these requirements. In addition, some of the existing time operation -1 means minus one month, and some minus one day, which is easy for users to confuse

Target

• Other date built-in variables are calculated relative to run_date
• Support Pattern format time and users can specify at will
• Support ±y/±M/±d/±H etc.

Pattern format comparison table:

Letter	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
Y	Week year	Year	2009; 09
M	Month in year	Month	July; Jul; 07
w	Week in year	Number	27
W	Week in month	Number	2
D	Day in year	Number	189
d	Day in month	Number	10
F	Day of week in month	Number	2
E	Day name in week	Text	Tuesday; Tue
e	Day number of week (1 = Monday, …, 7 = Sunday)	Number	1
a	Am/pm marker	Text	PM
H	Hour in day (0-23)	Number	0
k	Hour in day (1-24)	Number	24
K	Hour in am/pm (0-11)	Number	0
h	Hour in am/pm (1-12)	Number	12
m	Minute in hour	Number	30
s	Second in minute	Number	55
S	Millisecond	Number	978
z	Time zone	General time zone	Pacific Standard Time; PST; GMT-08:00
Z	Time zone	RFC 822 time zone	-0800
X	Time zone	ISO 8601 time zone	-08; -0800; -08:00

2. Overall Design

The overall design and technical architecture refer to Linkis Custom Variables

3. Function introduction

• The variable types supported by Linkis are divided into custom variables (not to be repeated) and system built-in variables. The custom variable date supports +-.
• Among them, +- is to perform operation on the built-in parameter run_date of linkis, and then replace the pattern field before %. Non-pattern characters do not support operation replacement.

3.1 Examples of built-in variables

You can define parameters that need to be dynamically rendered according to your own preferences/business actual situation

variable	result
&{yyyy-01-01}	2021-01-01
&{yyyy-01-01%-2y}	2019-01-01
&{yyyy-MM-01%-2M}	2021-02-01
&{yyyy-MM-dd%-2d}	2021-03-31
&{yyyy MM ----- HH%-1H}	2021 04 ----- 14
&{yyyyMMdd%-1d}	20210401
&{yyyyMM01%-1M}	20210301
&{HH%-1H}	14

3.2 Custom Variable Usage Example

• Example 1: sql

SELECT * FROM hive.tmp.fund_nav_histories
WHERE dt <= DATE_FORMAT(DATE_ADD('day', -1, DATE(Date_parse('&{yyyyMMdd%-1d}', '%Y%m%d'))), '%Y%m%d')

after rendering

SELECT * FROM hive.tmp.fund_nav_histories
WHERE dt <= DATE_FORMAT(DATE_ADD('day', -1, DATE(Date_parse('20220705', '%Y%m%d'))), '%Y%m%d')

• Example 2: shell

aws s3 ls s3://***/ads/tmp/dws_member_active_detail_d_20210601_20211231/pt=&{yyyyMMdd%-1d}/

after rendering

aws s3 ls s3://***/ads/tmp/dws_member_active_detail_d_20210601_20211231/pt=20220705/

• Example 3: datax json

{
  "job": {
    "setting": {
      "speed": {
        "channel": 1
      }
    },
    "content": [
      {
        "reader": {
          "name": "s3reader",
          "parameter": {
            "bucket": "****************",
            "path": [
              "ads/tmp/ccass_tm_announcements/&{yyyyMMdd%-1d}/"
            ],
            "stored": "parquet",
            "compression": "NONE",
            "column": [
              {
                "index": 0,
                "type": "int"
              },
              {
                "index": 1,
                "type": "string",
                "constant": "&{yyyyMMdd%-1d}"
              }
            ]
          }
        },
        "writer": {
          "name": "streamwriter",
          "parameter": {
            "print": true
          }
        }
      }
    ]
  }
}

after rendering

{
  "job": {
    "setting": {
      "speed": {
        "channel": 1
      }
    },
    "content": [
      {
        "reader": {
          "name": "s3reader",
          "parameter": {
            "bucket": "****************",
            "path": [
              "ads/tmp/ccass_tm_announcements/20220705/"
            ],
            "stored": "parquet",
            "compression": "NONE",
            "column": [
              {
                "index": 0,
                "type": "int"
              },
              {
                "index": 1,
                "type": "string",
                "constant": "20220705"
              }
            ]
          }
        },
        "writer": {
          "name": "streamwriter",
          "parameter": {
            "print": true
          }
        }
      }
    ]
  }
}

• Example 4: python

print(&{yyyyMMdd%-1d})

after rendering

 20220705