Variables Syntax

The system supports Jinja variable references with {{ }} syntax in all recipe files—JSON files, and others that might be executed in a node, such as a SQL file.

Overview

• Variable references for string values are typically enclosed in quotes and/or curly braces, such as {"key":"xyz{{variable_name}}12345".
• Variable references for dictionaries in keys, steps, and mappings can be written as {"key":{{dictionary_variable_name}} }.
• Specific variable references, such as test variables (shown below) and credentials defined as JSON dictionaries like "config-ref": "mssqlConfig", require syntax without the Jinja braces.

See Basic Jinja Variable References for more information.

Example

action_node/actions/create-order-dimensions.json

{
  "name": "create-order-dimensions",
  "type": "DKDataSource_MSSQL",
  "config": {
    "username": "{{mssqlConfig.username}}",  // Use Jinja syntax to reference these tool connection credentials stored in kitchen overrides
    "password": "{{mssqlConfig.password}}",
    "hostname": "{{mssqlConfig.hostname}}",
    "port": "",
    "database": "{{mssqlConfig.database}}"
    // Alternatively, reference a JSON dictionary variable pre-defined with all of the credentials: "config-ref": "mssqlConfig"
  },
  "keys": {
    "Create_Order_Line_Dimension_Table": {
      "sql": "{{load_text(sqlFileName)}}",  // Built-in function load_text loads a SQL file from the recipe's /resources directory
        // The filename is parameterized as the variable sqlFileName
        // Note, this SQL file includes Jinja expressions to call the {{schema_name}} variable
      "query-type": "execute_scalar",
      "set-runtime-vars": {
        "result": "dimension_table_order_line_count"  // This step in the action node record results as variable values, which are then used in tests
      }
    },
    "Query_Stage_Table_Order_Line_Count": {
      "sql": "SELECT COUNT(*) FROM {{schema_name}}.{{table_name}}",  // Where schema_name are variables used in SQL statements
      "query-type": "execute_scalar",
      "set-runtime-vars": {
        "result": "stage_table_order_line_count"  // This step in the action node record results as variable values, which are then used in tests
      }
    }
  },
  "tests": {
    "Ensure_Order_Line_Counts_Equal": {
      "action": "warning",
      "test-variable": "dimension_table_order_line_count",  // Reference test variables in quotes without curly-braces
      "type": "test-contents-as-integer",
      "test-logic": {
        "test-compare": "equal-to",
        "test-metric": "stage_table_order_line_count"  // Reference test variables in quotes without curly-braces
      },
      "keep-history": true
    },
    "Ensure_Order_Line_Counts_Always_Increasing": {
      "action": "stop-on-error",
      "test-variable": "dimension_table_order_line_count",  // Compares a test variable to the previous value of the same variable
      "type": "test-contents-as-integer",
      "test-logic": {
        "test-compare": "greater-than-equal-to",
        "test-metric": {
          "historic-calculation": "previous-value",
          "historic-metric": "dimension_table_order_line_count"  // Compares a test variable to the previous value of the same variable
        }
      },
      "keep-history": true
    }
  }
}