Add a simple HTTP resolver

This adds a simple HTTP resolver that can fetch a file from a remote
HTTP(S) URL.

Only fetch timeout configuration for now is supported.

This is kept simple for now, and does not support any kind of HTTP
authentication, custom TLS or any other features. Something we can
improve on later.

Signed-off-by: Chmouel Boudjnah <chmouel@redhat.com>

cmd/resolvers/main.go

@@ -25,6 +25,7 @@ import (
 	"github.com/tektoncd/pipeline/pkg/resolution/resolver/cluster"
 	"github.com/tektoncd/pipeline/pkg/resolution/resolver/framework"
 	"github.com/tektoncd/pipeline/pkg/resolution/resolver/git"
+	"github.com/tektoncd/pipeline/pkg/resolution/resolver/http"
 	"github.com/tektoncd/pipeline/pkg/resolution/resolver/hub"
 	filteredinformerfactory "knative.dev/pkg/client/injection/kube/informers/factory/filtered"
 	"knative.dev/pkg/injection/sharedmain"
@@ -40,7 +41,8 @@ func main() {
 		framework.NewController(ctx, &git.Resolver{}),
 		framework.NewController(ctx, &hub.Resolver{TektonHubURL: tektonHubURL, ArtifactHubURL: artifactHubURL}),
 		framework.NewController(ctx, &bundle.Resolver{}),
-		framework.NewController(ctx, &cluster.Resolver{}))
+		framework.NewController(ctx, &cluster.Resolver{}),
+		framework.NewController(ctx, &http.Resolver{}))
 }
 
 func buildHubURL(configAPI, defaultURL, yamlEndpoint string) string {

config/resolvers/http-resolver-config.yaml

@@ -0,0 +1,26 @@
+# Copyright 2023 The Tekton Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: http-resolver-config
+  namespace: tekton-pipelines-resolvers
+  labels:
+    app.kubernetes.io/component: resolvers
+    app.kubernetes.io/instance: default
+    app.kubernetes.io/part-of: tekton-pipelines
+data:
+  # The maximum amount of time the http resolver will wait for a response from the server.
+  fetch-timeout: "1m"

docs/http-resolver.md

@@ -0,0 +1,77 @@
+<!--
+---
+linkTitle: "HTTP Resolver"
+weight: 311
+---
+-->
+
+# HTTP Resolver
+
+This resolver responds to type `http`.
+
+## Parameters
+
+| Param Name       | Description                                                                   | Example Value                                              |
+|------------------|-------------------------------------------------------------------------------|------------------------------------------------------------|
+| `url`            | The URL to fetch from                                                         | https://raw.githubusercontent.com/tektoncd-catalog/git-clone/main/task/git-clone/git-clone.yaml                                                   |
+
+A valid URL must be provided. Only HTTP or HTTPS URLs are supported.
+
+## Requirements
+
+- A cluster running Tekton Pipeline v0.41.0 or later.
+- The [built-in remote resolvers installed](./install.md#installing-and-configuring-remote-task-and-pipeline-resolution).
+- The `enable-http-resolver` feature flag in the `resolvers-feature-flags` ConfigMap in the
+  `tekton-pipelines-resolvers` namespace set to `true`.
+- [Beta features](./additional-configs.md#beta-features) enabled.
+
+## Configuration
+
+This resolver uses a `ConfigMap` for its settings. See
+[`../config/resolvers/http-resolver-config.yaml`](../config/resolvers/http-resolver-config.yaml)
+for the name, namespace and defaults that the resolver ships with.
+
+### Options
+
+| Option Name                 | Description                                          | Example Values         |
+|-----------------------------|------------------------------------------------------|------------------------|
+| `fetch-timeout`              | The maximum time any fetching of URL resolution may take. **Note**: a global maximum timeout of 1 minute is currently enforced on _all_ resolution requests. | `1m`, `2s`, `700ms`                                              |
+
+## Usage
+
+### Task Resolution
+
+```yaml
+apiVersion: tekton.dev/v1beta1
+kind: TaskRun
+metadata:
+  name: remote-task-reference
+spec:
+  taskRef:
+    resolver: http
+    params:
+    - name: url
+    value: https://raw.githubusercontent.com/tektoncd-catalog/git-clone/main/task/git-clone/git-clone.yaml
+```
+
+### Pipeline Resolution
+
+```yaml
+apiVersion: tekton.dev/v1beta1
+kind: PipelineRun
+metadata:
+  name: http-demo
+spec:
+  pipelineRef:
+    resolver: http
+    params:
+    - name: url # optional
+      value: https://raw.githubusercontent.com/tektoncd/catalog/main/pipeline/build-push-gke-deploy/0.1/build-push-gke-deploy.yaml
+```
+
+---
+
+Except as otherwise noted, the content of this page is licensed under the
+[Creative Commons Attribution 4.0 License](https://creativecommons.org/licenses/by/4.0/),
+and code samples are licensed under the
+[Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0).

pkg/apis/config/resolver/feature_flags.go

@@ -33,6 +33,8 @@ const (
 	DefaultEnableBundlesResolver = true
 	// DefaultEnableClusterResolver is the default value for "enable-cluster-resolver".
 	DefaultEnableClusterResolver = true
+	// DefaultEnableHttpResolver is the default value for "enable-http-resolver".
+	DefaultEnableHttpResolver = true
 
 	// EnableGitResolver is the flag used to enable the git remote resolver
 	EnableGitResolver = "enable-git-resolver"
@@ -42,6 +44,8 @@ const (
 	EnableBundlesResolver = "enable-bundles-resolver"
 	// EnableClusterResolver is the flag used to enable the cluster remote resolver
 	EnableClusterResolver = "enable-cluster-resolver"
+	// EnableHttpResolver is the flag used to enable the http remote resolver
+	EnableHttpResolver = "enable-http-resolver"
 )
 
 // FeatureFlags holds the features configurations
@@ -51,6 +55,7 @@ type FeatureFlags struct {
 	EnableHubResolver     bool
 	EnableBundleResolver  bool
 	EnableClusterResolver bool
+	EnableHttpResolver    bool
 }
 
 // GetFeatureFlagsConfigName returns the name of the configmap containing all
@@ -90,6 +95,9 @@ func NewFeatureFlagsFromMap(cfgMap map[string]string) (*FeatureFlags, error) {
 	if err := setFeature(EnableClusterResolver, DefaultEnableClusterResolver, &tc.EnableClusterResolver); err != nil {
 		return nil, err
 	}
+	if err := setFeature(EnableHttpResolver, DefaultEnableHttpResolver, &tc.EnableHttpResolver); err != nil {
+		return nil, err
+	}
 	return &tc, nil
 }
 

pkg/apis/config/resolver/feature_flags_test.go

@@ -38,6 +38,7 @@ func TestNewFeatureFlagsFromConfigMap(t *testing.T) {
 				EnableHubResolver:     true,
 				EnableBundleResolver:  true,
 				EnableClusterResolver: true,
+				EnableHttpResolver:    true,
 			},
 			fileName: "feature-flags-empty",
 		},
@@ -47,6 +48,7 @@ func TestNewFeatureFlagsFromConfigMap(t *testing.T) {
 				EnableHubResolver:     false,
 				EnableBundleResolver:  false,
 				EnableClusterResolver: false,
+				EnableHttpResolver:    false,
 			},
 			fileName: "feature-flags-all-flags-set",
 		},
@@ -68,6 +70,7 @@ func TestNewFeatureFlagsFromEmptyConfigMap(t *testing.T) {
 		EnableHubResolver:     resolver.DefaultEnableHubResolver,
 		EnableBundleResolver:  resolver.DefaultEnableBundlesResolver,
 		EnableClusterResolver: resolver.DefaultEnableClusterResolver,
+		EnableHttpResolver:    resolver.DefaultEnableHttpResolver,
 	}
 	verifyConfigFileWithExpectedFeatureFlagsConfig(t, FeatureFlagsConfigEmptyName, expectedConfig)
 }

pkg/apis/config/resolver/testdata/feature-flags-all-flags-set.yaml

@@ -22,3 +22,4 @@ data:
   enable-hub-resolver: "false"
   enable-bundles-resolver: "false"
   enable-cluster-resolver: "false"
+  enable-http-resolver: "false"

pkg/resolution/resolver/http/config.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2023 The Tekton Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package http
+
+const (
+	// timeoutKey is the configuration field name for controlling
+	// the maximum duration of a resolution request for a file from http.
+	timeoutKey = "fetch-timeout"
+)

pkg/resolution/resolver/http/params.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2023 The Tekton Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package http
+
+const (
+	// urlParam is the url to fetch the task from
+	urlParam string = "url"
+)