Lint your LookML.
Provides additional linting checks beyond what is built into the LookML Validator.
From the CLI:
$ lookmlint lint ~/my-lookml-repo
For structured output, set the --json
flag:
$ lookmlint lint ~/my-lookml-repo --json
lookmlint
looks for a file named .lintconfig.yml
in your lookML project repo.
Its contents can contain lists of abbreviations and/or acronyms you'd like to flag, as well as any checks you'd like to run. More detail below.
abbreviations:
- num
- qty
acronyms:
- aov
- sms
- sku
- sla
timeframes:
- date
- month
- month_name
- time
- year
checks:
- label-issues
- unused-includes
- unused-view-files
- mismatched-view-names
- semicolons-in-derived-table-sql
- missing-view-sql-definitions
- raw-sql-in-joins
Requires python3
.
$ pip install lookmlint
LookML automatically converts snake case strings (e.g. unit_cost_usd
) to title case (e.g. Unit Cost Usd
), which looks funny when using acronyms. Leverages the list of acronyms defined in .lintconfig.yml
.
Bad
dimension: unit_cost_usd {
...
}
Good
dimension: unit_cost_usd {
label: "Unit Cost (USD)"
...
}
If you'd prefer some words fully spelled out (e.g. 'Quantity' instead of 'Qty'), define a list of abbreviations for lookmlint
to catch.
Joins should refer to LookML dimensions as opposed to the underlying fields where possible.
For example:
Bad
join: order_items {
sql_on: orders.id = order_items.order_id ;;
}
Good
join: order_items {
sql_on: ${orders.id} = ${order_items.order_id} ;;
}
Find all date/datetime/time dimensions or dimension groups that are missing any of the timeframes defined in .lintconfig.yml
.
If your LookML model explicitly specifies views to include, lookmlint
can catch views that are include
d in your model but not referenced in any of the explorations in that model.
Find all view files that aren't referenced in any explorations in your project.
Find all view files that don't contain a primary_key
dimension.
Find any cases when two join
s in an exploration end up with the same label.
One way this can unwittingly creep into code is if a label
is defined in a view file, that view is joined twice to the same exploration, but view_label
s are not assigned to those joins.
Find any views that do not have a sql_table_name
or derived_table
value set.
Find any derived table SQL expressions that contain a rogue semicolon, which will throw errors at query time.
Find any views where the view name does not match the view filename.
The sample repo at examples/sample_repo/
contains instances of all linting violations:
~/src/lookmlint $$$ lookmlint lint examples/sample_repo/
Error:
duplicate-view-labels
---------------------
Model: test
Explore: inventory_transfers
Inventory Locations: 2
label-issues
------------
Fields:
View: order_items
- Qty: ['Qty']
- Unit Cost Usd: ['USD']
missing-timeframes
-----------
View: items
Field: Created
- Missing Timeframe(s): ['month_name', 'time']
View: orders
Field: Placed
- Missing Timeframe(s): ['date', 'month', 'month_name', 'time', 'year']
mismatched-view-names
---------------------
- items.view.lkml: order_items
missing-view-sql-definitions
----------------------------
- order_items
raw-sql-in-joins
----------------
Model: test
Explore: orders
order_items: orders.id = order_items.order_id
semicolons-in-derived-table-sql
-------------------------------
- products
unused-includes
---------------
Model: test
- web_sessions
unused-view-files
-----------------
- legacy_products
- web_sessions
views-missing-primary-keys
--------------------------
- order_items
We use CircleCI at Warby Parker to run our checks.
Adding the following contents to .circleci/config.yml
in your LookML project should work for running linting as part of your CI/CD workflow. This all runs in a few seconds, but leveraging caching could also help to speed things up.
Customize the list of checks you run to suit your team's needs, or leave out the --checks
flag to run all possible lint checks.
version: 2
jobs:
build:
docker:
- image: circleci/python:3.6.2-stretch
working_directory: ~/repo
steps:
- checkout
- run:
name: Install lookmlint
command: |
sudo pip install lookmlint
- run:
name: Lint lookml
command: |
lookmlint lint . --checks label-issues,unused-includes,unused-view-files,mismatched-view-names,semicolons-in-derived-table-sql,missing-view-sql-definitions
This repo is still in alpha, so use at your own risk!
Please open an issue for any feature suggestions or bugs, or feel free to open a PR with a fix / feature!