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Overview

SDF supports macro processing with Jinja.

  • Jinja Files - SDF requires macro definitions to be in .jinja files
  • Preprocessor configuration - SDF Requires a workspace to turn on the jinja preprocessor
  • SDF provides some built in functions

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Getting Started With Jinja

Let’s explore some of the capabilities unlocked by using jinja in a minimal SDF workspace.

1

Create a new SDF Workspace

Create a new SDF workspace. sdf new jinjex && cd jinjex

2

Configure Your Workspace to Use Jinja

Add a new preprocessor property to the workspace block in your workspace.sdf.yml

workspace.sdf.yml
    workspace:
      name: jinjex
      defaults:
        preprocessor: jinja
      ...

Congratulations! Your workspace is now configured to run with Jinja.

3

Add a Jinja Expression to main.sql

Replace the contents of /models/main.sql with a short jinja expression like:

select 
{% for i in range (1, 5)%}
{{i}} as col_{{i}},
{% endfor %}
;

This expression creates a table with four columns.

Compile To see the schema, run:

sdf compile main

Schema jinjex.pub.main
+-------------+------------------+------------+
| column_name | data_type        | classifier |
+-------------+------------------+------------+
| col_1       | integer not null |            |
| col_2       | integer not null |            |
| col_3       | integer not null |            |
| col_4       | integer not null |            |
+-------------+------------------+------------+

Run To execute the SQL statement using SDF as the database target, simply run:

sdf run main

Table jinjex.pub.main
+-------+-------+-------+-------+
| col_1 | col_2 | col_3 | col_4 |
+-------+-------+-------+-------+
| 1     | 2     | 3     | 4     |
+-------+-------+-------+-------+
4

Creating a New Jinja Function

Let’s create a new function. This function will be accessible globally in your workspace. To start, create a new folder macros and add a new file macros.jinja to the folder.

Add the new directory to your includes in the workspace.

workspace.sdf.yml
workspace:
    ...
    includes:
    - path: models   
    - path: macros # <-- add this
    ...

In your macros.jinja file add a new function which we’ll call switch_schema

macros.jinja
{% macro switch_schema(schema_name, table_name) -%}
    {%- if schema_name is none -%}
        {{ default_schema }}.{{table_name}}
    {%- else -%}
        {{schema_name}}.{{table_name}}
    {%- endif -%}

{%- endmacro %}

Macros by default inherit their namespace from the Workspace name, in this case jinjex To reference any macro defined in your workspace, specify it with the namespace like jinjex.<function>(params)

Check that the function is included by running sdf compile. The output should be all green.

5

Using the Jinja function

It’s time to reference the function. Let’s create a new SQL file, child.sql in the /models folder.

models/child.sql
CREATE TABLE {{ jinjex.switch_schema("private", "child") }}
AS
SELECT col_1, col_3 
FROM main;

We are invoking the fucntion jinjex.switch_schema, and creating a new table, in that new schema.

Let’s verify that we are now compiling two tables with sdf compile --show all.

We can also easily confirm the lineage for our new table - jinjex.private.child by running sdf lineage jinjex.private.child

Table: jinjex.private.child
private.child.col_1
│
│ copy
└──────┐
    main.col_1

private.child.col_3
│
│ copy
└──────┐
    main.col_3

Or, if we wanted to execute these SQL statements, you simply run sdf run

Table jinjex.pub.main
+-------+-------+-------+-------+
| col_1 | col_2 | col_3 | col_4 |
+-------+-------+-------+-------+
| 1     | 2     | 3     | 4     |
+-------+-------+-------+-------+
1 rows.

Table jinjex.private.child
+-------+-------+
| col_1 | col_3 |
+-------+-------+
| 1     | 3     |
+-------+-------+

For additional resources on effectively using macros, please see SDF docs on:

Intro to JinjaJinja Variables