OCM-5281 | Feat | Add regions support from ocm shards (#882)

* Add regions support from ocm shards

* Removed unnecessary comment

* Added contains logic instead of the exact match for getting the region

* Changed method to check for regionaname

* Removed todo comment

* Fixed example

* Changed environment to stage in example

examples/regionalized_list_versions.go

@@ -0,0 +1,82 @@
+/*
+Copyright (c) 2023 Red Hat, Inc.
+
+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.
+*/
+
+// This example shows how to retrieve the collection of clusters from a specific OCM region
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	sdk "github.com/openshift-online/ocm-sdk-go"
+	cmv1 "github.com/openshift-online/ocm-sdk-go/clustersmgmt/v1"
+	"github.com/openshift-online/ocm-sdk-go/logging"
+)
+
+func main() {
+	// Create a context:
+	ctx := context.Background()
+
+	// Create a logger that has the debug level enabled:
+	logger, err := logging.NewGoLoggerBuilder().
+		Debug(true).
+		Build()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Can't build logger: %v\n", err)
+		os.Exit(1)
+	}
+
+	regValue, err := sdk.GetRhRegion("https://api.stage.openshift.com", "rh-singapore")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Can't find region: %v", err)
+		os.Exit(1)
+	}
+	token := os.Getenv("OCM_TOKEN")
+
+	// Build a regionalized connection based on the desired shard
+	connection, err := sdk.NewConnectionBuilder().
+		Logger(logger).
+		Tokens(token).
+		URL(fmt.Sprintf("https://%s", regValue.URL)). // Apply the region URL
+		BuildContext(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Can't build connection: %v\n", err)
+		os.Exit(1)
+	}
+	defer connection.Close()
+
+	// Get the client for the resource that manages the collection of clusters:
+	collection := connection.ClustersMgmt().V1().Versions()
+
+	// Retrieve the list of clusters using pages of ten items, till we get a page that has less
+	// items than requests, as that marks the end of the collection:
+	// Retrieve the page:
+	response, err := collection.List().
+		SendContext(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Can't retrieve versions : %s\n", err)
+		os.Exit(1)
+	}
+
+	// Display the page:
+	response.Items().Each(func(version *cmv1.Version) bool {
+		fmt.Printf("%s\n", version.ID())
+		return true
+	})
+
+}

rh_region.go

@@ -0,0 +1,60 @@
+package sdk
+
+import (
+	json2 "encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+type Region struct {
+	URL string
+	AWS []string
+	GCP []string
+}
+
+func GetRhRegions(ocmServiceUrl string) (map[string]Region, error) {
+	var regions map[string]Region
+	url, err := DetermineRegionDiscoveryUrl(ocmServiceUrl)
+	if err != nil {
+		return regions, fmt.Errorf("Can't determine region discovery URL: %s\n", err)
+	}
+	// Adding nolint here in order to prevent linter from failing due to variable http get
+	resp, err := http.Get(url) //nolint
+	if err != nil {
+		return regions, fmt.Errorf("Can't retrieve shards: %s", err)
+	}
+	err = json2.NewDecoder(resp.Body).Decode(&regions)
+	if err != nil {
+		return regions, fmt.Errorf("Can't decode shards: %s", err)
+	}
+	return regions, nil
+}
+
+func GetRhRegion(ocmServiceUrl string, regionName string) (Region, error) {
+	regions, err := GetRhRegions(ocmServiceUrl)
+	if err != nil {
+		return Region{}, err
+	}
+	for regName, regValue := range regions {
+		if regName == regionName {
+			return regValue, nil
+		}
+	}
+	return Region{}, fmt.Errorf("Can't find region %s", regionName)
+}
+
+func DetermineRegionDiscoveryUrl(ocmServiceUrl string) (string, error) {
+	baseUrl, err := url.Parse(ocmServiceUrl)
+	if err != nil {
+		return "", err
+	}
+	regionDiscoveryHost := "api.openshift.com"
+	if strings.HasSuffix(baseUrl.Hostname(), "integration.openshift.com") {
+		regionDiscoveryHost = "api.integration.openshift.com"
+	} else if strings.HasSuffix(baseUrl.Hostname(), "stage.openshift.com") {
+		regionDiscoveryHost = "api.stage.openshift.com"
+	}
+	return fmt.Sprintf("https://%s/static/ocm-shards.json", regionDiscoveryHost), nil
+}