TSQLLint

TSQLLint is a tool for describing, identifying, and reporting the presence of anti-patterns in TSQL scripts.

Installation

TSQLLint currently officially supports installation with dotnet-tool, Homebrew, and NPM.

Install with dotnet tool

$ dotnet tool install --global TSQLLint

Install with Homebrew

For OSX and Linux the recommended method of installing TSQLLint is to install the tool using homebrew.

$ brew tap tsqllint/homebrew-tsqllint
$ brew install tsqllint

Upgrade with Homebrew

$ brew upgrade tsqllint 

Install with NPM

TSQLLint may also be installed with NPM

This binary can be installed though the npm registry. First, install Node.js version 4 or higher, and then install using the npm install command:

npm install tsqllint -g

Usage

# lint a single file
tsqllint test.sql

# fix all auto-fixable problems (--fix or -x)
tsqllint --fix test.sql

# lint all files in a directory
tsqllint c:\database_scripts

# lint a list of files and directories, paths with whitespace must be enclosed in quotes
tsqllint file_one.sql file_two.sql "c:\database scripts"

# lint using wild cards
tsqllint c:\database_scripts\sp_*.sql

# print path to .tsqllintrc config file
tsqllint --print-config

# display usage info
tsqllint --help

# list the plugins loaded
tsqllint --list-plugins

Integrating TSQLLint with other Tools

Visual Studio Code Extension

In addition to the CLI tool, TSQLLint is built into a Visual Studio Code Extension. This extension can be installed from within the VS Code Extension Interface or from the VS Code Extension marketplace.

SQL Server Management Studio

TSQLLint uses a common message format that allows for integration into off the shelf tools. SQL Server Management Studio can use TSQLLint using SSMS's External Tools feature.

Configuration

TSQLLint utilizes a configuration file called .tsqllintrc. This file can be generated and edited by users to create their own configurations. To generate this file use the -i or --init flags. If no .tsqllintrc is found the tool will use a default configuration loaded in memory.

# generate a default .tsqllintrc file using the init flag (optional if just using a default configuration)
tsqllint --init

Creating custom configurations

To configure TSQLLint edit its config file, which is named .tsqllintrc. To find its location run tsqllint with the --print-confg or -p option.

TSQLLint will load its config file in the following order or precedence:

1. The value passed with the -c command line argument, if one is passed
2. An Environment Variable named TSQLLINTRC
3. A file named .tsqllintrc in the same local directory in which TSQLLint is executing
4. A file named .tsqllintrc in the user's home directory

Rule configuration

TSQLLint rules may be set to "off", "warning", or "error". Rules that are violated and are set to "error" will result in TSQLLint returning a non-zero exit code. Rules that are violated, but configured to "warning" will result in a zero exit code, but a warning message will be displayed in the shell output. Rules that are set to "off" will be completely ignored. Rules that are not present in the .tsqllintrc configuration are set to "off"

{
  "rules": {
    "case-sensitive-variables": "error",
    "conditional-begin-end": "error",
    "count-star": "error",
    "cross-database-transaction": "error",
    "data-compression": "error",
    "data-type-length": "error",
    "delete-where": "error",
    "disallow-cursors": "error",
    "full-text": "error",
    "information-schema": "error",
    "keyword-capitalization": "error",
    "linked-server": "error",
    "multi-table-alias": "error",
    "named-constraint": "error",
    "non-sargable": "error",
    "object-property": "error",
    "print-statement": "error",
    "schema-qualify": "error",
    "select-star": "error",
    "semicolon-termination": "error",
    "set-ansi": "error",
    "set-nocount": "error",
    "set-quoted-identifier": "error",
    "set-transaction-isolation-level": "error",
    "set-variable": "error",
    "update-where": "error",
    "upper-lower": "error",
    "unicode-string": "error"
  }
}

Disabling Rules with Inline Comments

To temporarily disable all rule warnings in a script, use comments in the following format:

/* tsqllint-disable */

SELECT * FROM FOO;

/* tsqllint-enable */

To disable or enable warnings for specific rules:

/* tsqllint-disable select-star */

SELECT * FROM FOO;

/* tsqllint-enable select-star */

To disable warnings for the entire script, place a /_ tsqllint-disable _/ comment at the top of the file:

/* tsqllint-disable */

SELECT * FROM FOO;

To disable specific rule warnings for the entire script place a comment similar to the following at the top of the file:

/* tsqllint-disable select-star */

SELECT * FROM FOO;

SQL Compatibility Level

TSQLLint provides a configurable "compatibility-level" that aligns with SQL Server's Compatibility Level. The value defaults to 120 but may be changed with the following edit to the .tsqllintrc or by using inline comments within the SQL file. TSQLLint supports the following compatibility levels 80, 90, 100, 110, 120, 130, 140, and 150.

Setting a default Compatibility Level using .tsqllintrc

Setting the compatibility level within the .tsqllintrc file configures the default Compatibility Level for all files.

{
  "rules": {
    "upper-lower": "error"
  },
  "compatibility-level": 90
}

Setting Compatibility Level Using Inline Comments

Setting the compatibility level using inline comments configures the Compatibility Level for just that file. Overrides should be placed at the top of files.

/* tsqllint-override compatibility-level = 130 */

SELECT * FROM FOO;

SQL Placeholders

Many tools in the SQL ecosystem support placeholders to templatize SQL files as shown in the example below:

SELECT * FROM FOO WHERE BAR = '$(MyPlaceholderValue)';

Before applying any linting rules, TSQLLint will replace any placeholder in a SQL file with values provided via environment variables.

Plugins

You can extend the base functionality of TSQLLint by creating a custom plugin. TSQLLint plugins are Dotnet assemblies that implement the IPlugin interface from TSQLLint.Common. Ensure the plugin is targeting net6.0.

After developing the plugin, update the .tsqllintrc file to point to its .dll.

{
  "rules": {
    "upper-lower": "error"
  },
  "plugins": {
    "my-first-plugin": "c:/users/someone/my-plugins/my-first-plugin.dll",
    "my-second-plugin": "c:/users/someone/my-plugins/my-second-plugin.dll/"
  }
}

This sample plugin notifies users that spaces should be used rather than tabs.

using System;
using System.Collections.Generic;
using System.IO;
using Microsoft.SqlServer.TransactSql.ScriptDom;
using TSQLLint.Common;

namespace TSQLLint_Sample_Plugin
{
    public class SamplePlugin : IPlugin
    {
        // This method is required but can be a no-op if using the GetRules method to parse code through the plugin's rules.
        public void PerformAction(IPluginContext context, IReporter reporter)
        {
            string line;
            var lineNumber = 0;

			var reader = new IO.StreamReader(File.OpenRead(context.FilePath));

            while ((line = reader.ReadLine()) != null)
            {
                lineNumber++;
                var column = line.IndexOf("\t", StringComparison.Ordinal);
                reporter.ReportViolation(new SampleRuleViolation(
                    context.FilePath,
                    "prefer-tabs",
                    "Should use spaces rather than tabs",
                    lineNumber,
                    column,
                    RuleViolationSeverity.Warning));
            }
        }

        // Starting with TSQLLint.Common version 3.3.0, this method can be used to return rules to be used by the TSQLLint parser.
        public IDictionary<string, ISqlLintRule> GetRules() => new Dictionary<string, ISqlLintRule>
        {
            ["sample-plugin-rule"] = new SampleRule((Action<string, string, int, int>)null)
        };
    }

    class SampleRuleViolation : IRuleViolation
    {
        public int Column { get; set; }
        public string FileName { get; private set; }
        public int Line { get; set; }
        public string RuleName { get; private set; }
        public RuleViolationSeverity Severity { get; private set; }
        public string Text { get; private set; }

        public SampleRuleViolation(string fileName, string ruleName, string text, int lineNumber, int column, RuleViolationSeverity ruleViolationSeverity)
        {
            FileName = fileName;
            RuleName = ruleName;
            Text = text;
            Line = lineNumber;
            Column = column;
            Severity = ruleViolationSeverity;
        }
    }

    class SampleRule : TSqlFragmentVisitor, ISqlLintRule
    {
        protected readonly Action<string, string, int, int> ErrorCallback;

        public SampleRule(Action<string, string, int, int> errorCallback)
        {
            ErrorCallback = errorCallback;
        }

        public string RULE_NAME => "sample-plugin-rule";
        public string RULE_TEXT => "Sample plugin rule message text";
        public RuleViolationSeverity RULE_SEVERITY => RuleViolationSeverity.Warning;

        public override void Visit(TSqlScript node)
        {
            var line = 0;
            var column = 0;

            // Logic for testing TSQL code for rule goes here.

            ErrorCallback(RULE_NAME, RULE_TEXT, line, column);
        }

        public void FixViolation(List<string> fileLines, IRuleViolation ruleViolation, FileLineActions actions)
        {
            // Logic for fixing rule violation goes here.
        }
    }
}