Set public Tekton Hub API as default catalog

Public tekton hub API was not set by default in the hub resolver, i
understand that ArtifactHUB is the future but until then
makes it more easier to use the tekton hub

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

config/resolvers/resolvers-deployment.yaml

@@ -102,6 +102,8 @@ spec:
       # Override this env var to set a private hub api endpoint
         - name: ARTIFACT_HUB_API
           value: "https://artifacthub.io/"
+        - name: TEKTON_HUB_API
+          value: "https://api.hub.tekton.dev/"
         securityContext:
           allowPrivilegeEscalation: false
           readOnlyRootFilesystem: true

docs/hub-resolver.md

@@ -64,7 +64,10 @@ env
   value: "https://artifacthub.io/"
 ```
 
-When setting the `type` field to `tekton`, you **must** configure your own instance of the Tekton Hub by setting the `TEKTON_HUB_API` environment variable in
+When setting the `type` field to `tekton`, the resolver will hit the public
+tekton catalog api at https://api.hub.tekton.dev by default but you can configure
+your own instance of the Tekton Hub by setting the `TEKTON_HUB_API` environment
+variable in
 [`../config/resolvers/resolvers-deployment.yaml`](../config/resolvers/resolvers-deployment.yaml). Example:
 
 ```yaml

go.mod

@@ -190,7 +190,7 @@ require (
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
-	github.com/hashicorp/go-version v1.6.0 // indirect
+	github.com/hashicorp/go-version v1.6.0
 	github.com/imdario/mergo v0.3.13 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect

pkg/resolution/resolver/hub/params.go

@@ -16,9 +16,15 @@ package hub
 // DefaultArtifactHubURL is the default url for the Artifact hub api
 const DefaultArtifactHubURL = "https://artifacthub.io/api/v1/packages/tekton-%s/%s/%s/%s"
 
+// DefaultArtifactHubListVersionHub is the default url for listing tasks version with Artifact hub api
+const DefaultArtifactHubListVersionHub = "https://artifacthub.io/api/v1/packages/tekton-%s/%s/%s"
+
 // TektonHubYamlEndpoint is the suffix for a private custom Tekton hub instance
 const TektonHubYamlEndpoint = "v1/resource/%s/%s/%s/%s/yaml"
 
+// TektonHubListVersionEndpoint is the endpoint url for listing tasks version with Tekton hub api
+const TektonHubListVersionEndpoint = "v1/resource/%s/%s/%s"
+
 // ArtifactHubYamlEndpoint is the suffix for a private custom Artifact hub instance
 const ArtifactHubYamlEndpoint = "api/v1/packages/tekton-%s/%s/%s/%s"
 

pkg/resolution/resolver/hub/resolver.go

@@ -22,8 +22,10 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"os"
 	"strings"
 
+	goversion "github.com/hashicorp/go-version"
 	resolverconfig "github.com/tektoncd/pipeline/pkg/apis/config/resolver"
 	pipelinev1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1"
 	"github.com/tektoncd/pipeline/pkg/resolution/common"
@@ -121,6 +123,14 @@ func (r *Resolver) Resolve(ctx context.Context, params []pipelinev1.Param) (fram
 		return nil, fmt.Errorf("failed to validate params: %w", err)
 	}
 
+	if constraint, err := goversion.NewConstraint(paramsMap[ParamVersion]); err == nil {
+		chosen, err := resolveVersionConstraint(ctx, paramsMap, constraint)
+		if err != nil {
+			return nil, err
+		}
+		paramsMap[ParamVersion] = chosen.String()
+	}
+
 	resVer, err := resolveVersion(paramsMap[ParamVersion], paramsMap[ParamType])
 	if err != nil {
 		return nil, err
@@ -218,7 +228,6 @@ func fetchHubResource(ctx context.Context, apiEndpoint string, v interface{}) er
 	if err != nil {
 		return fmt.Errorf("error unmarshalling json response: %w", err)
 	}
-
 	return nil
 }
 
@@ -256,6 +265,75 @@ func resolveCatalogName(paramsMap, conf map[string]string) (string, error) {
 	return paramsMap[ParamCatalog], nil
 }
 
+type artifactHubListResult struct {
+	AvailableVersions []struct {
+		Version    string `json:"version"`
+		Prerelease bool   `json:"prerelease"`
+	} `json:"available_versions"`
+	Version string `json:"version"`
+}
+
+type tektonHubListResult struct {
+	Data struct {
+		Versions []struct {
+			Version string `json:"version"`
+		} `json:"versions"`
+	} `json:"data"`
+}
+
+func resolveVersionConstraint(ctx context.Context, paramsMap map[string]string, constraint goversion.Constraints) (*goversion.Version, error) {
+	var ret *goversion.Version
+	if paramsMap[ParamType] == ArtifactHubType {
+		allVersionsURL := fmt.Sprintf(DefaultArtifactHubListVersionHub,
+			paramsMap[ParamKind], paramsMap[ParamCatalog], paramsMap[ParamName])
+		resp := artifactHubListResult{}
+		if err := fetchHubResource(ctx, allVersionsURL, &resp); err != nil {
+			return nil, fmt.Errorf("fail to fetch Artifact Hub resource: %w", err)
+		}
+		for _, vers := range resp.AvailableVersions {
+			if vers.Prerelease {
+				continue
+			}
+			checkV, err := goversion.NewVersion(vers.Version)
+			if err != nil {
+				return nil, fmt.Errorf("fail to parse version %s from %s: %w", ArtifactHubType, vers.Version, err)
+			}
+			if constraint.Check(checkV) {
+				if ret != nil && ret.GreaterThan(checkV) {
+					continue
+				}
+				ret = checkV
+				break
+			}
+		}
+	} else if paramsMap[ParamType] == TektonHubType {
+		//TODO: refactor url building
+		allVersionsURL := fmt.Sprintf("%s/%s", os.Getenv("TEKTON_HUB_API"),
+			fmt.Sprintf(TektonHubListVersionEndpoint, paramsMap[ParamCatalog], paramsMap[ParamKind], paramsMap[ParamName]))
+		resp := tektonHubListResult{}
+		if err := fetchHubResource(ctx, allVersionsURL, &resp); err != nil {
+			return nil, fmt.Errorf("fail to fetch Tekton Hub resource: %w", err)
+		}
+		for _, vers := range resp.Data.Versions {
+			checkV, err := goversion.NewVersion(vers.Version)
+			if err != nil {
+				return nil, fmt.Errorf("fail to parse version %s from %s: %w", TektonHubType, vers, err)
+			}
+			if constraint.Check(checkV) {
+				if ret != nil && ret.GreaterThan(checkV) {
+					continue
+				}
+				ret = checkV
+				break
+			}
+		}
+	}
+	if ret == nil {
+		return nil, fmt.Errorf("no version found for constraint %s", paramsMap[ParamVersion])
+	}
+	return ret, nil
+}
+
 // the Artifact Hub follows the semVer (i.e. <major-version>.<minor-version>.0)
 // the Tekton Hub follows the simplified semVer (i.e. <major-version>.<minor-version>)
 // for resolution request with "artifact" type, we append ".0" suffix if the input version is simplified semVer