Google OAuth connect and disconnect (Feature 16) (#125)

Co-authored-by: orchestrator-agent <20+orchestrator-agent@code.cubecraftcreations.com>

internal/config/config.go

@@ -29,6 +29,9 @@ const (
 	EnvOIDCClientSecretFile = "MEALQUEST_OIDC_CLIENT_SECRET_FILE"
 	EnvOIDCAllowedGroups    = "MEALQUEST_OIDC_ALLOWED_GROUPS"
 
+	EnvGoogleClientID         = "MEALQUEST_GOOGLE_CLIENT_ID"
+	EnvGoogleClientSecretFile = "MEALQUEST_GOOGLE_CLIENT_SECRET_FILE"
+
 	EnvSessionIdle = "MEALQUEST_SESSION_IDLE"
 	EnvSessionMax  = "MEALQUEST_SESSION_MAX"
 
@@ -61,6 +64,12 @@ type Config struct {
 	// OIDCAllowedGroups lists the groups whose members may sign in.
 	OIDCAllowedGroups []string
 
+	// GoogleClientID and GoogleClientSecret are the Google OAuth web client
+	// Push to Calendar connects with. Its redirect URI is PublicURL's origin
+	// followed by /api/v1/integrations/google/callback.
+	GoogleClientID     string
+	GoogleClientSecret Secret
+
 	// SessionIdle ends a session left unused this long.
 	SessionIdle time.Duration
 	// SessionMax ends every session this long after sign-in, used or not.
@@ -110,6 +119,9 @@ func load(lookup func(string) (string, bool)) (Config, error) {
 		OIDCClientSecret:  r.secretFile(EnvOIDCClientSecretFile),
 		OIDCAllowedGroups: r.list(EnvOIDCAllowedGroups),
 
+		GoogleClientID:     r.str(EnvGoogleClientID),
+		GoogleClientSecret: r.secretFile(EnvGoogleClientSecretFile),
+
 		SessionIdle: r.sessionDuration(EnvSessionIdle, DefaultSessionIdle),
 		SessionMax:  r.sessionDuration(EnvSessionMax, DefaultSessionMax),