About project definition files¶

Access template defaults¶

Template defaults let you access default and automatically-generated fields from a project definition file, even if the fields are not explicitly defined. To illustrate, consider the following Snowflake Native App project definition file:

definition_version: 1.1
native_app:
  name: myapp
  artifacts:
    - src: app/*
      dest: ./

This definition provides enough information to create a Snowflake Native App, so the default values for the application package and application instance are automatically generated when you create the application. You can then access these values using the following syntax:

• In SQL code

  &{ ctx.native_app.application.name }
  &{ ctx.native_app.package.name }
  

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• In other code languages

  <% ctx.native_app.application.name %>
  <% ctx.native_app.package.name %>
  

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fn.concat_ids()¶

• Input: one or more string arguments (SQL ID or plain String)

• Output: a valid SQL ID (quoted or unquoted)

The fn.concat_ids() function concatenates multiple string arguments into a single string representing a SQL ID (quoted or unquoted). If any of the input strings is a valid quoted identifier, it will be unescaped before the concatenation. The resulting string is then escaped and quoted if it contains non-SQL safe characters or if any of the input strings was a valid quoted identifier.

Examples:

• Calling fn.concat_ids('id1_', '"quoted_id2"') outputs "id1_quoted_id2" because one of the input values is a quoted identifier.

• Calling fn.concat_ids('id1_', 'id2') outputs id1_id2 because none of the input values is a quoted identifier and none of the input values contains non SQL safe characters.

fn.str_to_id()¶

• Input: one or more string arguments (SQL ID or plain String)

• Output: a valid SQL ID (quoted or unquoted)

The fn.str_to_id() function returns a string as a an ID. If the input string contains a valid quoted or unquoted identifier, the function returns it as is. However, if the input string contains unsafe SQL characters that are not properly quoted, the function returns a quoted ID that escapes the unsafe characters.

Examples:

• Calling fn.str_to_id('id1') returns id1 because it is a valid unquoted identifier.

• Calling fn.str_to_id('unsafe"id') returns "unsafe""id" because it contains unsafe SQL characters.

fn.id_to_str()¶

• Input: one string argument (SQL ID or plain String)

• Output: a plain string

If the input is a valid SQL ID, the function returns an unescaped plain String. Otherwise, the function returns the input string as is.

Examples:

• Calling :fn.id_to_str('id1'), returns id1 because it is already unquoted.

• Calling :codenowrap:` fn.id_to_str(‘“quoted””id.example”’)` returns quoted"id.example.

fn.get_username()¶

• Input: one optional string containing the fallback value

• Output: current username detected from the Operating System

Returns the current username from the operating system environment variables. If the current username is not found or is empty, it will either return an empty value or use the fallback value if one is provided.

Examples:

• fn.get_username('default_user') returns the current username if found, otherwise, it returns default_user.

fn.sanitize_id()¶

• Input: one string argument

• Output: a valid non-quoted SQL ID

The function fn.sanitize_id() removes any unsafe SQL characters from the input and returns it as a valid unquoted SQL ID. If the result does not start with a letter or an underscore, it appends an underscore to it. For very long strings, the function truncates the string to 255 characters.

Examples:

• When using fn.sanitize_id('Some.id"With_Special_Chars') the output is SomeidWith_Special_Chars.

• When using fn.sanitize_id('1abc') the output is _1abc.

Sample use case¶

The following example shows how to use these functions in snowflake.yml project definition files:

definition_version: 1.1
native_app:
  name: myapp_base_name_<% fn.sanitize_id(fn.get_username()) %>
  artifacts:
    - src: app/*
      dest: ./
  package:
    name: <% fn.concat_ids(ctx.native_app.name, ctx.env.pkg_suffix) %>
  application:
    name: <% fn.concat_ids(ctx.native_app.name, ctx.env.app_suffix) %>

env:
  app_suffix: _app_instance
  pkg_suffix: _pkg

The following example illustrates how to use the functions in a SQL file:

DESC APPLICATION &{ fn.str_to_id(ctx.native_app.application.name) };
DESC APPLICATION PACKAGE &{ fn.str_to_id(ctx.native_app.package.name) };