s3: Factor providers list out and auto generate textual version

backend/s3/s3.go

@@ -62,29 +62,17 @@ import (
 	"golang.org/x/net/http/httpguts"
 )
 
-// Register with Fs
-func init() {
-	fs.Register(&fs.RegInfo{
-		Name:        "s3",
-		Description: "Amazon S3 Compliant Storage Providers including AWS, Alibaba, ArvanCloud, Ceph, China Mobile, Cloudflare, GCS, DigitalOcean, Dreamhost, Huawei OBS, IBM COS, IDrive e2, IONOS Cloud, Leviia, Liara, Lyve Cloud, Minio, Netease, Petabox, RackCorp, Scaleway, SeaweedFS, StackPath, Storj, Synology, Tencent COS, Qiniu and Wasabi",
-		NewFs:       NewFs,
-		CommandHelp: commandHelp,
-		Config: func(ctx context.Context, name string, m configmap.Mapper, config fs.ConfigIn) (*fs.ConfigOut, error) {
-			switch config.State {
-			case "":
-				return nil, setEndpointValueForIDriveE2(m)
-			}
-			return nil, fmt.Errorf("unknown state %q", config.State)
-		},
-		MetadataInfo: &fs.MetadataInfo{
-			System: systemMetadataInfo,
-			Help:   `User metadata is stored as x-amz-meta- keys. S3 metadata keys are case insensitive and are always returned in lower case.`,
-		},
-		Options: []fs.Option{{
+// The S3 providers
+//
+// Please keep these in alphabetical order, but with AWS first and
+// Other last.
+//
+// NB if you add a new provider here, then add it in the setQuirks
+// function and set the correct quirks. Test the quirks are correct by
+// running the integration tests "go test -v -remote NewS3Provider:".
+var providerOption = fs.Option{
 	Name: fs.ConfigProvider,
 	Help: "Choose your S3 provider.",
-			// NB if you add a new provider here, then add it in the
-			// setQuirks function and set the correct quirks
 	Examples: []fs.OptionExample{{
 		Value: "AWS",
 		Help:  "Amazon Web Services (AWS) S3",
@@ -173,7 +161,41 @@ func init() {
 		Value: "Other",
 		Help:  "Any other S3 compatible provider",
 	}},
-		}, {
+}
+
+var providersList string
+
+// Register with Fs
+func init() {
+	var s strings.Builder
+	for i, provider := range providerOption.Examples {
+		if provider.Value == "Other" {
+			_, _ = s.WriteString(" and others")
+		} else {
+			if i != 0 {
+				_, _ = s.WriteString(", ")
+			}
+			_, _ = s.WriteString(provider.Value)
+		}
+	}
+	providersList = s.String()
+	fs.Register(&fs.RegInfo{
+		Name:        "s3",
+		Description: "Amazon S3 Compliant Storage Providers including " + providersList,
+		NewFs:       NewFs,
+		CommandHelp: commandHelp,
+		Config: func(ctx context.Context, name string, m configmap.Mapper, config fs.ConfigIn) (*fs.ConfigOut, error) {
+			switch config.State {
+			case "":
+				return nil, setEndpointValueForIDriveE2(m)
+			}
+			return nil, fmt.Errorf("unknown state %q", config.State)
+		},
+		MetadataInfo: &fs.MetadataInfo{
+			System: systemMetadataInfo,
+			Help:   `User metadata is stored as x-amz-meta- keys. S3 metadata keys are case insensitive and are always returned in lower case.`,
+		},
+		Options: []fs.Option{providerOption, {
 			Name:    "env_auth",
 			Help:    "Get AWS credentials from runtime (environment variables or EC2/ECS meta data if no env vars).\n\nOnly applies if access_key_id and secret_access_key is blank.",
 			Default: false,