GEP-1709: Conformance Profiles

• Issue: #1709
• Status: Experimental
• Probationary Period: Re-evaluate in April 2024

TLDR

Add high level profiles for conformance tests which implementations can select when running the conformance test suite. Also add opt-in automated conformance reporting to the conformance test suite to report conformance results back to the Gateway API project and receive recognition (e.g. badges).

Goals

• Add high-level profiles which downstream implementations can subscribe to in order to run tests for the associated supported feature sets.
• Add a reporting mechanism where conformance results can be reported back to the Gateway API project and provide “badges” to visibly decorate the implementations as conformant according to their profiles.
• Expand conformance testing documentation significantly so that it becomes the “landing zone” for new prospective implementations and provides a clear and iterative process for how to get started implementing Gateway API support.

Non-Goals

• We want to avoid adding any infrastructure for the reporting mechanism if feasible.
• For this iteration we don’t want to add configuration files for conformance tests, instead leaving that to future iterations and working on the raw machinery here (see alternatives considered).
• For this iteration we don’t want to add container images for conformance test runs, instead leaving that to future iterations (see alternatives considered.

Introduction

Since our conformance test suite was conceived of it’s been our desire to provide simple high level profiles that downstream implementations can subscribe to.

Today we have SupportedFeatures which get us some of what we want in terms of easily configuring the conformance test suite, but in this GEP we will describe taking that a step further (and a level higher) to create named profiles which indicate a “level of conformance” which implementations can prove they satisfy and receive certification for.

An API will be provided as the format for conformance test reports. We will provide tooling to assist with the reporting and certification process of submitting those reports and displaying the results.

API

The API for conformance profiles will include an API resource called ConformanceReport which will be at the center of a workflow that implementations can opt into to generate and submit those resources.

The workflow implementers will follow will include the following high-level steps:

1. select a profile
2. integrate tests in the downstream project
3. report results and get certified

The goal is to make selecting a conformance profile as simple and automatic of a process as feasible and support both the existing command line integration approach (e.g. go test) as well as a Golang approach using the conformance suite as a library.

Profiles

“Profiles” are effectively categories which represent the high-level grouping of tests related to some feature (or feature set) of Gateway API. When conformance is reported using one of these profiles extra features can be covered according to support levels:

• core
• extended

NOTE: implementation-specific doesn’t really have much in the way of tests today, but it is something users want to be able to display. We leave door open for it later and mention it in the alternatives considered section below.

We will start with the following named profiles:

• HTTP
• TLSPassthrough

These profiles correspond with *Route type APIs that we currently have tests for. As the tests roll in, we’ll also eventually have:

• UDP
• TCP
• GRPC

NOTE: In time we may have higher level groupings, like Layer4 (which would include at least TCP and UDP) but feedback from the community has been strong for a preference on the *Route level (see the alternatives considered for some more notes on this) for the moment.

NOTE: APIs that are referenced to or by *Route APIs will be tested as a part of a profile. For instance, running the HTTP profile will also run tests for GatewayClass and Gateway implicitly as these are required components of supporting HTTP.

The technical implementation of these profiles is very simple: effectively a “profile” is a static compilation of existing SupportedFeatures which represent the named category. Features that aren’t covered under a “core” level of support are opt-in.

Integration

Integrating the test suite into your implementation can be done using one of the following methods:

• The go test command line interface which enables projects of any language to run the test suite on any platform Golang supports.
• Using the conformance test suite as a Golang library within an already existing test suite.

NOTE: Usage as a library is already an established colloquialism in the community, this effort simply intends to make that more official.

Conformance profiles are passed as arguments when running the test suite. For instance when running via command line:

$ go test ./conformance/... -args -gateway-class=acme -conformance-profile=Layer7

Or the equivalent configuration using the Golang library:

cSuite, err := suite.New(suite.Options{
    GatewayClassName: "acme",
    Profiles: sets.New(Layer7),
    // other options
})
require.NoError(t, err, "misconfigured conformance test suite")
cSuite.Setup(t)
for i := 0; i < len(tests.ConformanceTests); i++ {
    test := tests.ConformanceTests[i]
    test.Run(t, cSuite)
}

NOTE: In the suite.Options above it’s still possible to add SkipTests but when used in conjunction with Profile this will result in a report that the profile is not valid for reporting. Implementations in this state may be able to report themselves as “in progress”, see the certification section for details.

Alternatively for an Extended conformance profile where not all of the features are implemented (as described in the profiles section above):

$ go test ./conformance/... -args \
    -gateway-class=acme \
    -conformance-profiles=HTTP,TCP \
    -unsupported-features=HTTPResponseHeaderModification,HTTPRouteMethodMatching,HTTPRouteQueryParamMatching,

Or the equivalent configuration using the Golang library:

cSuite, err := suite.New(suite.Options{
    GatewayClassName: "acme",
    Profiles: sets.New(
        HTTP,
        TCP,
    ),
    UnsupportedFeatures: sets.New(
        suite.SupportHTTPResponseHeaderModification,
        suite.SupportHTTPRouteMethodMatching,
        suite.SupportHTTPRouteQueryParamMatching,
    ),
    // other options
})
require.NoError(t, err, "misconfigured conformance test suite")
cSuite.Setup(t)
for i := 0; i < len(tests.ConformanceTests); i++ {
    test := tests.ConformanceTests[i]
    test.Run(t, cSuite)
}

NOTE: You can’t disable features that are Core conformance as Core is a minimum requirement for the profile to be considered fulfilled.

Some implementations may support more or less extended features than others, so in some cases it could be cumbersome to have to list ALL features that you don’t support so we optionally and inversely allow SupportedFeatures so you can pick which option makes sense to you, and under the hood the expressions will compile to the same overall list:

cSuite, err := suite.New(suite.Options{
    GatewayClassName: "acme",
    Profiles: sets.New(
        HTTP,
        TCP,
    ),
    SupportedFeatures: sets.New(
        suite.SupportHTTPRouteMethodMatching,
    ),
    // other options
})

NOTE: The UnsupportedFeatures and SupportedFeatures fields are mutually exclusive.

So to have your YAML report include details about extended features you support you must either opt-in using SupportedFeatures to the exact features you support, or opt-out of the features you don’t support using UnsupportedFeatures.

Once an implementation has integrated with the conformance test suite, they can move on to certification to report the results.

Implementation mode

The certification process runs against an implementation using a specific mode, specified in the final report’s “mode” field. A “mode” is intended to capture situations where a Gateway API implementation may have different features and capabilities depending on how it is deployed (e.g. an implementation might be deployed with an external, OR internal load balancer, and have different capabilities depending on the mode chosen). The modes are implementation-specific, and no upstream mode is defined, except for default, which is used in case no mode is specified.

Gateway API version and channel

The certification is related to a specific API version and a specific channel, therefore such information must be included in the final report. At test suite setup time, the conformance profile machinery gets all the CRDs with the field .spec.group equal to gateway.networking.k8s.io, and for each of them checks the annotations gateway.networking.k8s.io/bundle-version and gateway.networking.k8s.io/channel. If there are CRDs with different versions, the certification fails specifying that it’s not possible to run the tests as there are different Gateway API versions installed in the cluster. If there are CRDs with different channels, the certification fails specifying that it’s not possible to run the tests as there are different Gateway API channels installed in the cluster. If all the Gateway API CRDs have the same version and the same channel, the tests can be run and the detected version and channel will be set in the gatewayAPIVersion and gatewayAPIChannel fields of the final report. Furthermore, the suite must run all the experimental tests when the channel is experimental, and the related features are enabled.

In addition to the CRDs version, the suite needs to check its version in relation to the CRDs one. To do so, a new .go file containing the current Gateway API version is introduced in the project and compiled with the conformance profile suite:

const GatewayAPIVersion = "0.7.0"

At test suite setup time the conformance profile suite checks the CRDs version and the suite version; if the two versions differ, the certification fails. A new generator will be introduced in the project to generate the aforementioned .go file starting from a VERSION file contained in the root folder. Such a VERSION file contains the semver of the latest release and is manually bumped at release time. The script hack/verify-all.sh will be updated to ensure the generated .go file is up to date with the VERSION file.

Implementations will be able to report their conformance testing results using our reporting process. Implementations will be able to visibly demonstrate their conformance results on their downstream projects and repositories using our certification process.

Reporting process

When conformance tests are executed an argument can be provided to the test suite to emit ConformanceReport resource with the test results. This resource can be configured to emit to the test output itself, or to a specific file.

The following is an example report:

apiVersion: v1alpha1
kind: ConformanceReport
implementation:
  organization: acme
  project: operator
  url: https://acme.com
  contact:
  - @acme/maintainers
  version: v1.0.0
date: "2023-02-28 20:29:41+00:00"
gatewayAPIVersion: v0.8.0
gatewayAPIChannel: experimental
mode: default
profiles:
- name: http
  core:
    result: success
    summary: "all core functionality passed"
    statistics:
      passed: 20
      skipped: 0
      failed: 0
  extended:
    result: success
    summary: "all extended features supported"
    statistics:
      passed: 8
      skipped: 0
      failed: 0
    supportedFeatures:
    - ExtendedFeature1
    - ExtendedFeature2
    - ExtendedFeature3
    - ExtendedFeature4
    - ExtendedFeature5
- name: tcp
  core:
    result: success
    summary: "all core functionality passed"
    statistics:
      passed: 4
      skipped: 0
      failed: 0
  extended:
    result: skipped
    summary: "some extended features supported"
    statistics:
      passed: 2
      skipped: 0
      failed: 0
    supportedFeatures:
    - ExtendedFeature1
    - ExtendedFeature2
    unsupportedFeatures:
    - ExtendedFeature3

WARNING: It is an important clarification that this is NOT a full Kubernetes API. It uses TypeMeta for some fields that made sense to re-use and were familiar, but otherwise has it’s own structure. It is not a Custom Resource Definition (CRD) nor will it be made available along with our CRDs. It will be used only by conformance test tooling.

NOTE: The implementation field in the above example includes an organization and project field. Organizations can be an open source organization, an individual, a company, e.t.c.. Organizations can theoretically have multiple projects and should submit separate reports for each of them.

NOTE: The contact field indicates the Github usernames or team names of those who are responsible for maintaining this file, so they can be easily contacted when needed (e.g. for relevant release announcements regarding conformance, e.t.c.). Optionally, it can be an email address or a support URL (e.g. Github new issue page).

The above report describes an implementation that just released v1, uses gateway API v0.8.0 experimental channel, and has HTTP core and extended and TCP core and partial extended support in default mode.

Multiple reports

Multiple ConformanceReports can be stored as a list of reports for a specific Gateway API version. The following shows previous releases of the acme/operator implementation and its feature progression:

apiVersion: v1alpha1
kind: ConformanceReport
implementation:
  organization: acme
  project: operator
  url: https://acme.com
  contact:
  - @acme/maintainers
  version: v0.9.0
date: "2023-02-28 20:29:41+00:00"
gatewayAPIVersion: v0.8.0
gatewayAPIChannel: standard
mode: default
profiles:
- name: http
  core:
    result: success
    summary: "some core functionality passed"
    statistics:
      passed: 18
      skipped: 2
      failed: 0
    skippedTests:
    - CoreTest8
    - CoreTest15
  extended:
    result: success
    summary: "some extended features supported"
    statistics:
      passed: 8
      skipped: 0
      failed: 0
    supportedFeatures:
    - ExtendedFeature1
    - ExtendedFeature2
    unsupportedFeatures:
    - ExtendedFeature3
    - ExtendedFeature4
    - ExtendedFeature5

apiVersion: v1alpha1
kind: ConformanceReport
implementation:
  organization: acme
  project: operator
  url: https://acme.com
  contact:
  - @acme/maintainers
  version: v1.0.0
date: "2023-06-1 20:29:41+00:00"
gatewayAPIVersion: v1.0.0
gatewayAPIChannel: experimental
mode: default
profiles:
- name: http
  core:
    result: success
    summary: "all core functionality passed"
    statistics:
      passed: 20
      skipped: 0
      failed: 0
  extended:
    result: success
    summary: "all extended features supported"
    statistics:
      passed: 8
      skipped: 0
      failed: 0
    supportedFeatures:
    - ExtendedFeature1
    - ExtendedFeature2
    - ExtendedFeature3
    unsupportedFeatures:
    - ExtendedFeature4
    - ExtendedFeature5
- name: tcp
  core:
    result: success
    summary: "all core functionality passed"
    statistics:
      passed: 4
      skipped: 0
      failed: 0
  extended:
    result: skipped
    summary: "some extended features supported"
    statistics:
      passed: 2
      skipped: 0
      failed: 0
    supportedFeatures:
    - ExtendedFeature1
    - ExtendedFeature2
    unsupportedFeatures:
    - ExtendedFeature3

NOTE: In the above you can see the acme implementation’s progression. In their release v0.9.0 they had started adding HTTP support and added the conformance tests to CI, but they were still skipping some core tests. In their next release v1.0.0 they completed adding HTTP Core functionality (and even added three extended features), and also added TCP functionality with Core and partial Extended support.

NOTE: Implementations MUST report for a specific release version (e.g. v0.7.1) and not use branches or Git SHAs. Some exceptions will be made for initial reports to help make it easier for implementations to get started, but as we move to standard everyone should be reporting on specific releases.

Creating a pull request to add the ConformanceReport will start the certification process.

NOTE: No verification process (to prevent intentionally incorrect conformance results) will be implemented at this time. We expect that this wont be an issue in our community and even if someone were to try and “cheat” on the reporting the reputation loss for being caught would make them look very bad and would not be worth it.

Reports submission

Implementers can create as many reports as they want, with different API versions, API channels, modes, and implementation versions. The reports can be submitted upstream by creating a pull request to the Gateway API repository. The reports folder tree is the following:

|-- conformance/reports
|   |-- v1.0
|   |   |-- acme-operator
|   |   |   |-- README.md
|   |   |   |-- standard-v2.13-default-report.yaml
|   |-- v1.1
|   |   |-- acme-operator
|   |   |   |-- README.md
|   |   |   |-- standard-v2.14-default-report.yaml
|   |   |   |-- standard-v2.14-with-the-lot-report.yaml
|   |   |   |-- extended-v2.14-with-the-lot-report.yaml
|   |   |-- umbrella-operator
|   |   |   |-- README.md
|   |   |   |-- standard-v1.8-default-report.yaml

The main folder conformance/reports contains a set of sub-folders, each for a Gateway API version. Implementors will create their project folder in all the Gateway API version folders for which they have a supported implementation. The implementors folder contains the following set of files:

• README.md: contains general information about the implementation, a table of contents, and the instructions to reproduce the claimed report.
• <API-channel>-<implementation-version>-<mode-name>-report.yaml: the report generated by the conformance test suite for the specific mode.

README.md structure

The README.md files SHOULD be structured in the following way (enrichment from implementors is allowed, even though the minimum content is described below):

# Acme operator
General information about the Acme/operator project
## Table of contents
| API channel | Implementation version | Mode | Report |
|-------------|------------------------|------|--------|
|             |                        |      |        |
|             |                        |      |        |
|             |                        |      |        |
## To reproduce
Instructions on how to reproduce the claimed report.

Each row of the table of contents MUST correspond to an uploaded report and contains the most implementation version and the mode. An example follows:

NOTE: the column Report contains the link to the corresponding uploaded report.

NOTE: This table of contents could be improved in the future with a link to proof of conformance, such as artifacts containing logs.

Certification Process

The raw report data of the ConformanceReports is predominantly meant for machine consumption. Report data will be compiled into human-friendly displays during an automated certification process.

Certification starts with the pull request described during the reporting process. Once the ConformanceReport is created or updated a display layer in the implementations page will need to be updated to point to the new data.

NOTE: The ConformanceReport API will be defined in Golang like our other apis/ so that we can utilize build tags from kubebuilder for defaults and validation, and so that there exists a common Golang type for it in the conformance test suite. When PRs are created the Gateway API repositories’ CI will run linting and validation against the reports.

Maintainers will provide badges to implementations at the end of the process which link to the implementations page for that specific implementation and can be easily added via markdown to Git repositories.

Alternatives Considered

Conformance Test Configuration File

Conformance testing is currently done mainly through command line with go test or via use of the conformance test suite as a library in Golang projects. We considered whether adding the alternative to provide a configuration file to the test suite would be nice, but we haven’t heard any specific demand for that from implementors yet so we’re leaving the idea here for later iterations to consider.

Conformance Test Container Image

Providing a container image which could be fed deployment instructions for an implementation was considered while working on this GET but it seemed like a scope all unto itself so we’re avoiding it here and perhaps a later iteration could take a look at that if there are asks in the community.

Implementation-Specific Reporting

Users have mentioned the desire to report on implementation-specific features they support as a part of conformance. At the time of writing, there’s not much in the way of structure or testing for us to do this with but we remain open to the idea. The door is left open in the ConformanceReport API for a future iteration to add this if desired, but it probably warrants its own GEP as we need to make sure we have buy-in from multiple stakeholders with different implementations that are implementing those features.

High-Level Profiles

We originally started with two high-level profiles:

• Layer4
• Layer7

However, the overwhelming feedback from the community was to go a step down and define profiles at the level of each individual API (e.g. HTTPRoute, TCPRoute, GRPCRoute, e.t.c.). One of the main reasons for this was that we already have multiple known implementations of Gateway API which only support a single route type (UDPRoute, in particular as it turns out).

We may consider in the future doing some of these higher-level profiles if there’s a technical reason or strong desire from implementers.

Graduation Criteria

The following are items that MUST be resolved to move this GEP to Standard status (and before the end of the probationary period):

• some kind of basic level of display for the report data needs to exist. It’s OK for a more robust display layer to be part of a follow-up effort.
• for now we ended up with badges in our implementations page. We have another effort underway to build an even better display layer, but we consider this additive and the current display is sufficient for moving the project to standard.
• initially we were OK with storing reports in the Git repository as files. While this is probably sufficient during the Experimental phase, we need to re-evaluate this before Standard and see if this remains sufficient or if we want to store the data elsewhere.
• During the experimental phase this has not caused any significant issues, so for the purposes of calling this standard we’re going to move forward as-is. It should be straightforward and reasonable to change the storage mechanism later as needs arise.
• We have been actively gathering feedback from SIG Arch. Some time during the experimental phase needs to be allowed to continue to engage with SIG Arch and incorporate their feedback into the test suite.
• SIG Arch did not have any significant feedback during the experimental phase. In the same timespan the Network Policy group has started using our test suite and APIs as well, so it seems the overall approach has obvious merit, and doesn’t appear to be redundant.
• Finalize the report organization structure based on feedback during the experimental phase.
• Base documentation must exist for implementations to run the tests via the CLI and via the Golang library.

References

• https://github.com/kubernetes-sigs/gateway-api/issues/1709
• https://github.com/kubernetes-sigs/gateway-api/issues/1329