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spectral

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Spectral is a flexible JSON/YAML linter for creating automated style guides, with built-in support for OpenAPI (v3.1, v3.0, and v2.0), Arazzo v1.0, and AsyncAPI v2.x specifications.

Key Features:

  • Custom Rulesets: Create custom rules to lint JSON or YAML objects
  • Ready-to-use Rulesets: Validate and lint OpenAPI, AsyncAPI, and Arazzo documents out of the box
  • API Style Guides: Automated API style guides using rulesets improve consistency across all your APIs
  • Built-in Functions: Pattern checks, parameter validation, alphabetical ordering, character limits, and key presence validation
  • Custom Functions: Create advanced custom functions for complex use cases
  • Multiple Output Formats: Support for various output formats including SARIF, JUnit, HTML, and more

Spectral helps ensure your API specifications follow best practices and maintain consistency across your organization. It's particularly useful for enforcing API governance and automated quality checks in CI/CD pipelines.

spectral documentation

spectral - GitHub

Configuration in MegaLinter

Variable Description Default value
API_SPECTRAL_ARGUMENTS User custom arguments to add in linter CLI call
Ex: -s --foo "bar"
API_SPECTRAL_COMMAND_REMOVE_ARGUMENTS User custom arguments to remove from command line before calling the linter
Ex: -s --foo "bar"
API_SPECTRAL_FILTER_REGEX_INCLUDE Custom regex including filter
Ex: (src\|lib)		 Include every file
API_SPECTRAL_FILTER_REGEX_EXCLUDE Custom regex excluding filter
Ex: (test\|examples)		 Exclude no file
API_SPECTRAL_CLI_LINT_MODE Override default CLI lint mode
- file: Calls the linter for each file
- project: Call the linter from the root of the project		 file
API_SPECTRAL_FILE_EXTENSIONS Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all files
Ex: [".py", ""]		 [".yml", ".yaml", ".json"]
API_SPECTRAL_FILE_NAMES_REGEX File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files
Ex: ["Dockerfile(-.+)?", "Jenkinsfile"]		 Include every file
API_SPECTRAL_PRE_COMMANDS List of bash commands to run before the linter None
API_SPECTRAL_POST_COMMANDS List of bash commands to run after the linter None
API_SPECTRAL_UNSECURED_ENV_VARIABLES List of env variables explicitly not filtered before calling API_SPECTRAL and its pre/post commands None
API_SPECTRAL_CONFIG_FILE spectral configuration file nameUse LINTER_DEFAULT to let the linter find it .spectral.yaml
API_SPECTRAL_RULES_PATH Path where to find linter configuration file Workspace folder, then MegaLinter default rules
API_SPECTRAL_DISABLE_ERRORS Run linter but consider errors as warnings false
API_SPECTRAL_DISABLE_ERRORS_IF_LESS_THAN Maximum number of errors allowed 0
API_SPECTRAL_CLI_EXECUTABLE Override CLI executable ['spectral']

IDE Integration

Use spectral in your favorite IDE to catch errors before MegaLinter !

IDE Extension Name Install
stoplight Native integration Visit Web Site
Visual Studio Code vscode-spectral Visit Web Site

MegaLinter Flavors

This linter is available in the following flavors

Flavor Description Embedded linters Info
all Default MegaLinter Flavor 126 Docker Image Size (tag) Docker Pulls
c_cpp Optimized for pure C/C++ projects 56 Docker Image Size (tag) Docker Pulls
documentation MegaLinter for documentation projects 49 Docker Image Size (tag) Docker Pulls
dotnet Optimized for C, C++, C# or VB based projects 64 Docker Image Size (tag) Docker Pulls
dotnetweb Optimized for C, C++, C# or VB based projects with JS/TS 73 Docker Image Size (tag) Docker Pulls
go Optimized for GO based projects 51 Docker Image Size (tag) Docker Pulls
java Optimized for JAVA based projects 54 Docker Image Size (tag) Docker Pulls
javascript Optimized for JAVASCRIPT or TYPESCRIPT based projects 59 Docker Image Size (tag) Docker Pulls
php Optimized for PHP based projects 54 Docker Image Size (tag) Docker Pulls
python Optimized for PYTHON based projects 65 Docker Image Size (tag) Docker Pulls
ruby Optimized for RUBY based projects 50 Docker Image Size (tag) Docker Pulls
rust Optimized for RUST based projects 50 Docker Image Size (tag) Docker Pulls
salesforce Optimized for Salesforce based projects 54 Docker Image Size (tag) Docker Pulls
swift Optimized for SWIFT based projects 50 Docker Image Size (tag) Docker Pulls
terraform Optimized for TERRAFORM based projects 54 Docker Image Size (tag) Docker Pulls

Behind the scenes

How are identified applicable files

  • File extensions: .yml, .yaml, .json
  • Detected file content (regex): "asyncapi":, "openapi":, "swagger":, asyncapi:, openapi:, swagger:

How the linting is performed

  • spectral is called one time by identified file (file CLI lint mode)

Example calls

spectral lint myfile.yml

spectral lint -r .spectral.yaml myfile.yml

Help content

spectral lint [documents..]

lint JSON/YAML documents from files or URLs

Positionals:
  documents  Location of JSON/YAML documents. Can be either a file, a glob or fetchable resource(s) on the web.  [array] [default: []]

Options:
      --version                  Show version number  [boolean]
      --help                     Show help  [boolean]
  -e, --encoding                 text encoding to use  [string] [choices: "utf8", "ascii", "utf-8", "utf16le", "ucs2", "ucs-2", "base64", "latin1"] [default: "utf8"]
  -f, --format                   formatters to use for outputting results, more than one can be provided by using multiple flags  [string] [choices: "json", "stylish", "junit", "html", "text", "teamcity", "pretty", "github-actions", "sarif", "code-climate", "gitlab", "markdown"] [default: "stylish"]
  -o, --output                   where to output results, can be a single file name, multiple "output.<format>" or missing to print to stdout  [string]
      --stdin-filepath           path to a file to pretend that stdin comes from  [string]
      --resolver                 path to custom json-ref-resolver instance  [string]
  -r, --ruleset                  path/URL to a ruleset file  [string]
  -F, --fail-severity            results of this level or above will trigger a failure exit code  [string] [choices: "error", "warn", "info", "hint"] [default: "error"]
  -D, --display-only-failures    only output results equal to or greater than --fail-severity  [boolean] [default: false]
      --ignore-unknown-format    do not warn about unmatched formats  [boolean] [default: false]
      --fail-on-unmatched-globs  fail on unmatched glob patterns  [boolean] [default: false]
      --show-documentation-url   show documentation url in output result  [boolean] [default: false]
  -v, --verbose                  increase verbosity  [boolean]
  -q, --quiet                    no logging - output only  [boolean]

Installation on mega-linter Docker image

  • Dockerfile commands :
# renovate: datasource=npm depName=@stoplight/spectral-cli
ARG NPM_SPECTRAL_CLI_VERSION=6.15.0