Transformation rules inside mapper snap not exported to output file

[darshthakkar]

Hi Team,

I have found one of the transformational rules applied on “date field” not getting exported to the final output file (i.e. excel file) when the pipeline has been executed.
Output preview on the snap does show the right data (i.e. expected one), pipeline validation also shows the right data however the file which gets generated after pipeline execution doesn’t get those details.

I have tried the following:

• validated pipeline via shift+validate
• tweak the transformation rule, save the pipeline and check the output in the preview
• validated the preview file (with default 50 records)
• deleted the file generated by “validate & execute” snap on File writer with default 50 records so that new instance of data comes in
• executed the pipeline with different file name multiple times

It’s a simple pipeline consisting of

            Snowflake Execute --> Mapper --> Excel Formatter --> File Writer

Sharing some screenshots to help it understand better:
(1) Pipeline with 4 snaps

(2) Snowflake execute output preview in JSON format (highlighted yellow fields needs transformation)

(3) Transformation Rules on Date fields

(4) Transformation Rule: $Expire_Date.toString().replace('{Timestamp=',"").replace('.000+0000}',"Z")

(5) Output preview after transformational rule

(6) Mapper output preview shows different data

→ I’ve observed certain times that the transformation rules won’t work so I go inside the mapper, modify the rule a bit, bring it back to default rule so that I can save it (save is not enabled if there is no change thus this workaround)

(7) As shift+validate didn’t work, had to change the transformation rule, save it and then this is the output preview on mapper snap:

(8) Settings under excel formatter snap for reference:

(9) Settings under File Writer snap for reference:

(10) File generated with default 50 records due to validate & execute on File writer snap

(11) Downloaded the file that gets generated in step 10 and below is the output (expected)

(12) Executed Pipeline

(13) Output File of Executed pipeline

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I’ve seen this happening numerous times particularly to fields containing timestamp in other pipelines too, am I doing something wrong over here? Any settings that needs to be changed either in Mapper, Excel Formatter or File Writer snap?

Thanking in advance for your valuable time and suggestions on this one.

Best Regards,
DT

[j_angelevski]

Hi @darshthakkar,

Since the field you are transforming is a timestamp ( datetime ), it is a best practice to transform the date and format it with the built-in method .toLocaleDateTimeString({format: "yyyy-MM-dd'T'HH:mm:ss'Z'"}) instead of converting it to string and then manually replacing the timezone offset.

[darshthakkar]

Thank you @j.angelevski for the direction.
I will try your suggestion and keep you posted on how it goes, appreciate your help though!

Rationale behind converting it to String was: I wanted to export the raw data and it didn’t allow, error was “Flatten the file before export” thus .toString() was used. I wasn’t aware of the built-in method so THANK YOU for sharing that.

[darshthakkar]

j.angelevski:

it is a best practice to transform the date and format it with the built-in method .toLocaleDateTimeString({format: "yyyy-MM-dd'T'HH:mm:ss'Z'"})

With the above approach, the result in Date is coming as “Null”

Screenshots below for reference:

[robin]

@darshthakkar try

Date.parse($Expire_Date.Timestamp).toLocaleDateTimeString({format: "yyyy-MM-dd'T'HH:mm:ss'Z'"})

I believe that will do what you want