Configuration

SQLFluff accepts configuration either through the command line or through configuration files. There is rough parity between the two approaches with the exception that templating configuration must be done via a file, because it otherwise gets slightly complicated.

For details of what’s available on the command line check out the CLI Reference.

For file based configuration SQLFluff will look for the following files in order. Later files will (if found) will be used to overwrite any vales read from earlier files.

  • setup.cfg

  • tox.ini

  • pep8.ini

  • .sqlfluff

Within these files, they will be read like an cfg file, and SQLFluff will look for sections which start with SQLFluff, and where subsections are delimited by a semicolon. For example the jinjacontext section will be indicated in the section started with [sqlfluff:jinjacontext].

Nesting

SQLFluff uses nesting in its configuration files, with files closer overriding (or patching, if you will) values from other files. That means you’ll end up with a final config which will be a patchwork of all the values from the config files loaded up to that path. You don’t need any config files to be present to make SQLFluff work. If you do want to override any values though SQLFluff will use files in the following locations in order, with values from later steps overriding those from earlier:

  1. […and this one doesn’t really count] There’s a default config as part of the SQLFluff package. You can find this below, in the Default Configuration section.

  2. It will look in the user’s os-specific app config directory. On OSX this is ~/Library/Preferences/sqlfluff, Unix is ~/.config/sqlfluff, Windows is <home>AppDataLocalsqlfluffsqlfluff, for any of the filenames above in the main Configuration section. If multiple are present, they will patch/override each other in the order above.

  3. It will look for the same files in the user’s home directory (~).

  4. It will look for the same files in the current working directory.

  5. [if parsing a file in a subdirectory of the current working directory] It will look for the same files in every subdirectory between the current working dir and the file directory.

  6. It will look for the same files in the directory containing the file being linted.

This whole structure leads to efficient configuration, in particular in projects which utilise a lot of complicated templating.

Jinja Templating Configuration

When thinking about Jinja templating there are two different kinds of things that a user might want to fill into a templated file, variables and functions/macros. Currently functions aren’t implemented in any of the templaters.

Variable Templating

Variables are available in the jinja and python templaters. By default the templating engine will expect variables for templating to be available in the config, and the templater will be look in the section corresponding to the context for that templater. By convention, the config for the jinja templater is found in the sqlfluff:templater:jinja:context section and the config for the python templater is found in the sqlfluff:templater:python:context section.

For example, if passed the following .sql file:

SELECT {{ num_things }} FROM {{ tbl_name }} WHERE id > 10 LIMIT 5

…and the following configuration in .sqlfluff in the same directory:

[sqlfluff:templater:jinja:context]
num_things=456
tbl_name=my_table

…then before parsing, the sql will be transformed to:

SELECT 456 FROM my_table WHERE id > 10 LIMIT 5

Note

If there are variables in the template which cannot be found in the current configuration context, then this will raise a SQLTemplatingError and this will appear as a violation without a line number, quoting the name of the variable that couldn’t be found.

Complex Variable Templating

Two more advanced features of variable templating are case sensitivity and native python types. Both are illustrated in the following example:

[sqlfluff:templater:jinja:context]
my_list=['a', 'b', 'c']
MY_LIST=("d", "e", "f")
my_where_dict={"field_1": 1, "field_2": 2}
SELECT
    {% for elem in MY_LIST %}
        '{{elem}}' {% if not loop.last %}||{% endif %}
    {% endfor %} as concatenated_list
FROM tbl
WHERE
    {% for field, value in my_where_dict.items() %}
        {{field}} = {{value}} {% if not loop.last %}and{% endif %}
    {% endfor %}

…will render as…

SELECT
    'd' || 'e' || 'f' as concatenated_list
FROM tbl
WHERE
    field_1 = 1 and field_2 = 2

Note that the variable was replaced in a case sensitive way and that the settings in the config file were interpreted as native python types.

Macro Templating

Macros (which also look and feel like functions are available only in the jinja templater. Similar to Variable Templating, these are specified in config files, what’s different in this case is how they are named. Similar to the context section above, macros are configured separately in the macros section of the config. Consider the following example.

If passed the following .sql file:

SELECT {{ my_macro(6) }} FROM some_table

…and the following configuration in .sqlfluff in the same directory (note the tight control of whitespace):

[sqlfluff:templater:jinja:macros]
a_macro_def = {% macro my_macro(something) %}{{something}} + {{something * 2}}{% endmacro %}

…then before parsing, the sql will be transformed to:

SELECT 6 + 12 FROM some_table

Note that in the code block above, the variable name in the config is a_macro_def, and this isn’t apparently otherwise used anywhere else. Broadly this is accurate, however within the configuration loader this will still be used to overwrite previous values in other config files. As such this introduces the idea of config blocks which could be selectively overwritten by other configuration files downstream as required.

In addition to macros specified in the config file, macros can also be loaded from a file or folder. The path to this macros folder must be specified in the config file to function as below:

[sqlfluff:templater:jinja]
load_macros_from_path=my_macros

In this case, SQLFluff will load macros from any .sql file found at the path specified on this variable. The path is interpreted relative to the config file, and therefore if the config file above was found at /home/my_project/.sqlfluff then SQLFluff will look for macros in the folder /home/my_project/my_macros/. Alternatively the path can also be a .sql itself.

Note

Throughout the templating process whitespace will still be treated rigorously, and this includes newlines. In particular you may choose to provide your dummy macros in your configuration with different to the actual macros you may be using in production.

REMEMBER: The purpose of providing the option of macros is to enable the parsing of templated sql without it being a blocker. It shouldn’t be a requirement that the templating is accurate - only so far as that is required to enable the parsing and linting to be helpful.

Builtin Macro Blocks

One of the main use cases which inspired SQLFluff as a project was dbt. It uses jinja templating extensively and leads to some users maintaining large repositories of sql files which could potentially benefit from some linting.

Note

SQLFluff has now a tighter integration with dbt through the “dbt” templater. It is the recommended templater for dbt projects and removes the need for the overwrites described in this section.

To use the dbt templater, go to Dbt Project Configuration.

SQLFluff anticipates this use case and provides some built in macro blocks in the Default Configuration which assist in getting started with dbt projects. In particular it provides mock objects for:

  • ref: The mock version of this provided simply returns the model reference as the name of the table. In most cases this is sufficient.

  • config: A regularly used macro in dbt to set configuration values. For linting purposes, this makes no difference and so the provided macro simply returns nothing.

Note

If there are other builtin macros which would make your life easier, consider submitting the idea (or even better a pull request) on github.

dbt Project Configuration

Note

dbt templating is a new feature added in 0.4.0 and has not benefited from widespread use and testing yet! If you encounter an issue, please let us know in a Github issue or on the SQLFluff slack workspace.

dbt is not the default templater for SQLFluff (it is Jinja). For using SQLFluff with a dbt project, users can either use the jinja templater (which may be slightly faster, but will not support the full spectrum of macros) or the dbt templater, which uses dbt itself to render the sql (meaning that there is a much more reliable representation of macros, but a potential performance hit accordingly). At this stage we recommend that users try both approaches and choose according to the method that they indent to use SQLFluff.

A simple rule of thumb might be:

  • If you are using SQLFluff in a CI/CD context, where speed is not critical but accuracy in rendering sql is, then the dbt templater may be more appropriate.

  • If you are using SQLFluff in an IDE or on a git hook, where speed of response may be more important, then the jinja templater may be more appropriate.

In order to get started using SQLFluff with a dbt project you will need the following configuration:

In .sqlfluff:

[sqlfluff]
templater = dbt
# dbt templating does not keep trailing new lines (L009)
exclude_rules = L009

In .sqlfluffignore:

target/
dbt_modules/
macros/

Known Caveats

  • In SQLFluff 0.4.0 dbt templating only works if SQLFluff CLI commands are invoked from the dbt project’s root directory (containing dbt_project.yml). There is an issue to address this: https://github.com/sqlfluff/sqlfluff/issues/601

  • In SQLFluff 0.4.0 using the dbt templater requires that all files within the root and child directories of the dbt project must be part of the project. If there are deployment scripts which refer to SQL files not part of the project for instance, this will result in an error. You can overcome this by adding any non-dbt project SQL files to .sqlfluffignore.

CLI Arguments

You already know you can pass arguments (--verbose, --exclude_rules, etc.) through the CLI commands (lint, fix, etc.):

$ sqfluff lint my_code.sql -v -exclude_rules L022,L027

You might have arguments that you pass through every time, e.g rules you always want to ignore. These can also be configured:

[sqlfluff]
verbose = 1
exclude_rules = L022,L027

Note that while the exclude_rules config looks similar to the above example, the verbose config has an integer value. This is because verbose is stackable meaning there are multiple levels of verbosity that are available for configuration. See CLI Reference for more details about the available CLI arguments.

.sqlfluffignore

Similar to Git’s .gitignore and Docker’s .dockerignore, SQLFluff supports a .sqfluffignore file to control which files are and aren’t linted. Under the hood we use the python pathspec library which also has a brief tutorial in their documentation.

An example of a potential .sqfluffignore placed in the root of your project would be:

# Comments start with a hash.

# Ignore anything in the "temp" path
/path/

# Ignore anything called "testing.sql"
testing.sql

# Ignore any ".tsql" files
*.tsql

Ignore files can also be placed in subdirectories of a path which is being linted and the sub files will also be applied within that subdirectory.

Default Configuration

The default configuration is as follows, note the Builtin Macro Blocks in section [sqlfluff:templater:jinja:macros] as referred to above.

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[sqlfluff]
verbose = 0
nocolor = False
dialect = ansi
templater = jinja
rules = None
exclude_rules = None
recurse = 0
output_line_length = 80
runaway_limit = 10

[sqlfluff:indentation]
indented_joins = False
template_blocks_indent = True

[sqlfluff:templater:jinja]
apply_dbt_builtins = True

[sqlfluff:templater:jinja:macros]
# Macros provided as builtins for dbt projects
dbt_ref = {% macro ref(model_ref) %}{{model_ref}}{% endmacro %}
dbt_source = {% macro source(source_name, table) %}{{source_name}}_{{table}}{% endmacro %}
dbt_config = {% macro config() %}{% for k in kwargs %}{% endfor %}{% endmacro %}
dbt_var = {% macro var(variable) %}item{% endmacro %}
dbt_is_incremental = {% macro is_incremental() %}True{% endmacro %}

# Some rules can be configured directly from the config common to other rules.
[sqlfluff:rules]
tab_space_size = 4
max_line_length = 80
indent_unit = space
comma_style = trailing
allow_scalar = True
single_table_references = consistent
only_aliases = True

# Some rules have their own specific config.
[sqlfluff:rules:L003]
lint_templated_tokens = True

[sqlfluff:rules:L010]
capitalisation_policy = consistent

[sqlfluff:rules:L014]
capitalisation_policy = consistent

[sqlfluff:rules:L030]
capitalisation_policy = consistent