Move provider initialisation into providers package

pkg/apis/options/legacy_options.go

@@ -624,7 +624,7 @@ func (l *LegacyProvider) convert() (Providers, error) {
 		ClientID:          l.ClientID,
 		ClientSecret:      l.ClientSecret,
 		ClientSecretFile:  l.ClientSecretFile,
-		Type:              l.ProviderType,
+		Type:              ProviderType(l.ProviderType),
 		CAFiles:           l.ProviderCAFiles,
 		LoginURL:          l.LoginURL,
 		RedeemURL:         l.RedeemURL,

pkg/apis/options/providers.go

@@ -52,7 +52,7 @@ type Provider struct {
 	// Type is the OAuth provider
 	// must be set from the supported providers group,
 	// otherwise 'Google' is set as default
-	Type string `json:"provider,omitempty"`
+	Type ProviderType `json:"provider,omitempty"`
 	// Name is the providers display name
 	// if set, it will be shown to the users in the login page.
 	Name string `json:"name,omitempty"`
@@ -84,6 +84,56 @@ type Provider struct {
 	AcrValues string `json:"acrValues,omitempty"`
 }
 
+// ProviderType is used to enumerate the different provider type options
+// Valid options are: adfs, azure, bitbucket, digitalocean facebook, github,
+// gitlab, google, keycloak, keycloak-oidc, linkedin, login.gov, nextcloud
+// and oidc.
+type ProviderType string
+
+const (
+	// ADFSProvider is the provider type for ADFS
+	ADFSProvider ProviderType = "adfs"
+
+	// AzureProvider is the provider type for Azure
+	AzureProvider ProviderType = "azure"
+
+	// BitbucketProvider is the provider type for Bitbucket
+	BitbucketProvider ProviderType = "bitbucket"
+
+	// DigitalOceanProvider is the provider type for DigitalOcean
+	DigitalOceanProvider ProviderType = "digitalocean"
+
+	// FacebookProvider is the provider type for Facebook
+	FacebookProvider ProviderType = "facebook"
+
+	// GitHubProvider is the provider type for GitHub
+	GitHubProvider ProviderType = "github"
+
+	// GitLabProvider is the provider type for GitLab
+	GitLabProvider ProviderType = "gitlab"
+
+	// GoogleProvider is the provider type for GoogleProvider
+	GoogleProvider ProviderType = "google"
+
+	// KeycloakProvider is the provider type for Keycloak
+	KeycloakProvider ProviderType = "keycloak"
+
+	// KeycloakOIDCProvider is the provider type for Keycloak OIDC
+	KeycloakOIDCProvider ProviderType = "keycloak-oidc"
+
+	// LinkedInProvider is the provider type for LinkedIn
+	LinkedInProvider ProviderType = "linkedin"
+
+	// LoginGovProvider is the provider type for LoginGov
+	LoginGovProvider ProviderType = "login.gov"
+
+	// NextCloudProvider is the provider type for NextCloud
+	NextCloudProvider ProviderType = "nextcloud"
+
+	// OIDCProvider is the provider type for OIDC
+	OIDCProvider ProviderType = "oidc"
+)
+
 type KeycloakOptions struct {
 	// Group enables to restrict login to members of indicated group
 	Groups []string `json:"groups,omitempty"`