Allow Disenser as optional contract.

src/keeper/Keeper.ts

@@ -49,7 +49,7 @@ export class Keeper extends Instantiable {
         try {
             keeper.instances = await objectPromiseAll({
                 // Main contracts
-                dispenser: Dispenser.getInstance(config),
+                dispenser: undefined, // Optional
                 token: OceanToken.getInstance(config),
                 didRegistry: DIDRegistry.getInstance(config),
                 // Managers
@@ -78,6 +78,13 @@ export class Keeper extends Instantiable {
             return
         }
 
+        // Optionals
+        try {
+            keeper.instances.dispenser = await Dispenser.getInstance(config)
+        } catch {
+            keeper.logger.warn('Dispenser not available on this network.')
+        }
+
         // Main contracts
         keeper.dispenser = keeper.instances.dispenser
         keeper.token = keeper.instances.token

src/ocean/Account.ts

@@ -111,6 +111,9 @@ export default class Account extends Instantiable {
      */
     public async requestTokens(amount: number | string): Promise<string> {
         amount = String(amount)
+        if (!this.ocean.keeper.dispenser) {
+            throw new Error('Dispenser not available on this network.')
+        }
         try {
             await this.ocean.keeper.dispenser.requestTokens(amount, this.id)
         } catch (e) {