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A git-centric policy management and enforcement tool designed to accelerate your CI/CD pipelines.
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Red Light Green Light

A git-centric policy management and enforcement tool designed to accelerate your CI/CD pipelines

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Quick Start

Try out the hosted version at Note that documents expire after 7 days.

For an example of real-world rlgl policy in action, check out the policy used to validate unit test reports for libffi on travis-ci builds:

Download and install one of the cli tools hosted at Now login to the server like so...

$ rlgl login

You'll get a message back asking you to create a personal API key. Follow those instructions, and try again...

$ rlgl login --key=MY_PERSONAL_KEY

If you require the use of a proxy, specify like so:

$ rlgl login --proxy= --key=MY_PERSONAL_KEY

You can also specify a proxy username and password for basic proxy authentication:

$ rlgl login --proxy= \
             --proxy-auth=USERNAME:PASSWORD \

Generate and inspect a player ID, like so...

$ ID=$(rlgl start)
$ echo $ID

Generate an OpenSCAP report, or grab one from here:

$ curl > report.html

Evaluate the report against a sample policy:

$ rlgl evaluate --id=$ID --policy= report.html

Click on the resulting URL and explore. Try forking the test policy report and making changes.

Produce a log of reports for this player ID:

$ rlgl log --id=$ID

Problem Statement

Modern DevOps pipelines require Quality Gating mechanisms in order to fully automate the promotion of software artifacts from dev all the way through to prod. These Quality Gates are responsible for deciding whether or not a deployable artifact (config files, software builds, container images, VM images, etc) should proceed to the next stage of a CI/CD pipeline.

Many tools are available to evaluate the quality of deployable artifacts, including container image scanners, unit test harnesses, config file linters, etc. But dealing with multiple quality testing tools introduces problems:

  • bespoke gating mechanisms must be created to evaluate test results
  • different tools require different exception processes and policy management
  • no centralized, auditable policy management
  • policies are locked within proprietary tools

Policy Driven Quality Gates

The main idea behind Red Light Green Light is to decouple the process of evaluating test results away from the underlying testing tools themselves, in a way that is:

  • centrally managed
  • version controlled
  • auditable
  • customizeable
  • protected with authentication/authorization mechanisms

The goal of all of this is to enable auditors to easily answer the following questions as they relate to any artifact promoted through a CI/CD pipeline:

  • who presented test results for evaluation?
  • what were those test results?
  • what policies were they evaluated against?
  • who defined the policies and when?

The Red Light Green Light service is invoked via the rlgl command-line tool, typically within some other pipeline automation framework, such as a jenkins pipeline. Here's an example workflow:

  • First, we must log into our Red Light Green Light server with rlgl cli tool like so:
$ rlgl login
  • Each deployable artifact is given a Player ID. The Player ID is what flows down the pipeline along with the various build/deploy artifacts. They would be attached as artifact metadata.
$ ID=$(rlgl start)
  • As the pipeline proceeds, test results are generated (scans, unit tests, etc). For each test report generated, rlgl evaluates the report against the stated git-hosted policy, resulting in a Red Light, meaning stop the pipeline, or Green Light, meaning proceed with the pipeline. It also produces a URL that links to a report showing annotated evaluation results. Annotations, include, for example, the git logs for policies defining exceptions resulting in green lights.
$ rlgl evaluate --policy --id $ID my-test-report.html
$ rlgl evaluate --policy --id $ID oval-scan.xml
$ rlgl evaluate --policy --id $ID gcc.log

Standard exit codes make it easy to integrate rlgl into your CI/CD pipeline scripts. GREEN lights have an exit code of 0. RED lights have an exit code of 1. Any other exit code is an error.

That's it! The client side is very easy.

The server side, where policy is evaluated, is where the magic is.

The first step is to identify the type of report we're evaluating and convert it into a normalized form. The normalized form is defined simply as this: a sequence of JSON objects, one for each testcase result. This object has two required fields:

  • result: whose value is either PASS or FAIL.
  • id: a descriptive ID for the testcase (e.g. CVE number).

One optional field is:

  • url: a URL linking to contextual info for that id.

And then as many extra fields may be added to the JSON object as may be useful below.

Policies are maintained in git repos, and consist of three plain text files: XFAIL, FAIL, and PASS. Each of these files contains a list of JSON matchmaking expressions to match against the canonical test results. They are evaluated this order: XFAIL, FAIL, PASS.

XFAIL contains matchmakers for test results we are expecting to fail, but allowing to pass anyway. These are your exceptions. Any matching JSON objects are reported as green, and filtered out from the list of test results to be processed by FAIL.

FAIL contains matchmakers for tests results that are definitely failures. They are reported as red, and filtered out from the test results before processing with PASS.

PASS contains matchers for known test passes and reported as green.

Any remaining entries in the test results are recorded as UNKNOWN. rlgl interprets these as red, but they are reported as UNKNOWN in order aim for 100% coverage of the PASS/FAIL scans.

The XFAIL, FAIL, PASS files are maintained in a git repo. Changing policy requires modifying the policy in git, which is logged and auditable.

In addition to this simple test evaluation service, the server can report on which policies have received green lights for each Player ID, and records all test documents for archive and audit purposes. Reports submitted to and generated by Red Light Green Light are currently archived forever.

$ rlgl log --id=$ID
Tue, 29 Jan 2019 13:15:29 -0500 Green: 00430cf0324532aab032423
Tue, 29 Jan 2019 13:16:31 -0500 Green: 10430cf0324532aab032423
Tue, 29 Jan 2019 13:16:50 -0500 Green: 20430cf0324532aab032423
Tue, 29 Jan 2019 13:16:55 -0500   Red: 30430cf0324532aab032423

The format of this log is:


Policy in Detail

An rlgl policy consists of three separate files in a git repo: XFAIL, FAIL and PASS. Each file contains JSON matchmaking expressions, comments and blank lines. Comments are lines starting with the characters # or ;. The matchmaking expressions are single-line JSON objects.

For example, to mark a CVE failure as an exception, we add the following to our XFAIL file:

# Ignore this failure in our container images
{ "result": "FAIL", "id": "CVE-2014-4043" }

Each JSON field string must match the corresponding string in the test result object exactly. There are two special forms of string values. Strings starting with "^" are interpreted as regular expressions, and strings of the form "NUMBER..NUMBER" are interpreted as a numeric range.

So, for example, to ignore all CVE vulnerabilities from 2013 with a score of less than 7 we add the following to our XFAIL file:

# Ignore everything but the most critical CVEs from 2013.
{ "result": "FAIL", "id": "^CVE-2013.*", "score": "0..6" }

Every element of the matchmaking expression must match the test result in order to qualify as a match.

A matchmaking expression may be followed by an expiration date, a time after which the matchmaker no longer applies.

# Whitelist this failure until April 1, 2019 and 9am
{ "result": "FAIL", "id": "CVE-2014-4043" } 2019-04-01 9:00

The date expiration time can be in any of the following formats: RFC822 (RFC1123, RFC2822, RFC5322), asctime, RFC850 (RFC1036), ISO8601 (1988, 2000, 2004, except for no-year format), W3CDTF (subset of ISO 8601), RFC3339. Examples of these include:

  • Thu, 23 Jul 2013 19:42:23 GMT (RFC1123),
  • Thu Jul 23 19:42:23 2013 (asctime),
  • Thursday, 23-Jul-13 19:42:23 GMT (RFC1036),
  • 2013-07-23T19:42:23Z (RFC3339),
  • 20130723T194223Z (ISO8601:2004), etc.

Red Light Green Light will also do it's best to interpret variations of said standards, as in the example above (2019-04-01 9:00).

If a date is provided but no time, then it is interpreted as just after midnight at the start of the day.

JSON matchmaking expressions cannot span more than one line of text. This is required in order to attribute policy changes to individuals via git blame. These changelogs are available through the rlgl reports generated at evaluation time.

Report Parsers

Currently supported report parsers include:

  • Anchore container vulnerability json reports
  • AquaSec container microscanner reports
  • Clair container scanner json reports
  • DejaGnu testing framework
  • JUnit XML results report
  • OpenSCAP OVAL scan reports
  • OpenSCAP XCCDF scan reports
  • Comma separated values (CSV) for generic policy enforcement on arbitrary metrics (file size, performance results, etc).

Note that for the CSV parser, the first line of the CSV file defines the field strings used in the resulting JSON results objects. For example, this CSV file...

filename, filesize
a.out, 1234567
b.out, 87908

..produces the following JSON results objects...

{ "filename": "a.out", "filesize": "1234567" }
{ "filename": "b.out", "filesize": "87908" }

..for you to write policy against...

{ "filesize": "0..1000000" }

While the rlgl command-line tool is written in Go, the server side is written in Common Lisp, and adding additional report types requires modifying the rlgl-server lisp code. External parser support is planned, allowing you to invoke report parsers through a simple API.

Monitoring & Observability

The Red Light Green Light server exports Prometheus metrics on port 9101.

Author and License

Red Light Green Light was written by Anthony Green, and is distributed under the terms of the GNU Affero General Public License, Version 3. See COPYING for details.

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