[SEMANTIC-247] [Bug] Derived metrics with parenthesis in the expression cannot be calculated with metrics.develop macro

[josepfranquetf]

Is this a new bug in dbt_metrics?

• I believe this is a new bug in dbt_metrics
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

I have defined a derived metric (conversion_rate) which has the following expression:

- expression: number_of_orders/(0.9*sessions)

Where number_of_orders (count_distinct of a column) and sessions (sum of a column) are two simple metrics.

Additionally, I have used metrics.develop macro to calculate the value of conversion_rate using the following macro:

select * from {{metrics.develop(develop_yml=my_metrics_yml, metric_list=['conversion_rate'], grain='month')}}

And I have obtained this error:

syntax error line 89 at position 90 unexpected 'as'

After debugging the dbt-metrics package, I have got to the line 22 of the dbt_metrics/macros/variables/get_metric_definition.sql file and obtained what follows:

{% set metric_expression = metric_definition.expression | replace("metric(","") | replace(")","") | replace("{{","") | replace("}}","") | replace("'","") | replace('"',"") %}

It seems that this part of the code is removing the last parenthesis of the expression of the metric conversion_rate and causes the query to fail.

Expected Behavior

I would expect the metric could be calculated without any problem with metrics.develop macro.

Steps To Reproduce

See above.

Relevant log output

No response

Environment

- dbt-adapter & version:v1.4.1
- dbt_metrics version:v1.4.1

Which database adapter are you using with dbt?

snowflake

Additional Context

I have temporarily adjusted the dbt-metrics package code by replacing the code line mentioned above by a more concrete replacement expression:

{% set metric_expression = metric_definition.expression | replace(" ","") | replace("{{metric('","") | replace("')}}","") | replace("'","") | replace('"',"") %}

And it has worked without any problem.

[callum-mcdata]

@josepfranquetf wow, great find and beautiful that you found the fix as well! Could you submit a PR with your fix? We'll be releasing the 1.5 branch late this week/early next week and I'd love to make sure this is included. Unfortunately I don't have the bandwidth to take it on but I'm happy to review for you!

[josepfranquetf]

Hi @callum-mcdata, many thanks for your answer! I have just opened a PR, which you can find here. Tell me in case you need something else!

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