Cygnus SDK

The Cygnus SDK is a comprehensive tool designed specifically for the Internet Computer, offering convenient canister management with auto top-up and withdrawal functionality. This SDK package consists of two essential files:

Cygnus SDK Files in Motoko

1. Cygnus.mo: This file contains various types necessary for smooth integration. It also includes access control validation, ensuring that only whitelisted principlaIDs and Cygnus Canister have permission to access these methods.

2. Main.mo: This file includes two crucial methods that should be copied into the main actor of your canister.

Integration Steps

Integrating the Cygnus SDK into your canister involves the following steps:

1. Import Dependencies in the Actor file:

   Make sure to include the following dependencies in your main actor file if you haven't already done so:

   import Principal "mo:base/Principal";
   import Cycles "mo:base/ExperimentalCycles";

   Import the Cygnus dependency file into your main actor file:

   import Cygnus "Cygnus";

2. Add Principal ID to the array of whitelistedPrincipalIds in the Cygnus.mo file. Only whitelisted PrincipalID can register new canisters using the Cygnus front tool or Candid. To add a Principal ID, follow these steps: 1. Open the Cygnus.mo file. 2. Locate the whitelistedPrincipalIds array. 3. Add the desired Principal IDs as elements of the array. Example:

      let whitelistedPrincipalIds : [ Text ] = [
         "evwewe-w2wib-fjqum2-5cqnb-56v7f-xptd4-thtkc-vevew-riuws-5wug4-001",
         "evwewe-w2wib-fjqum2-5cqnb-56v7f-xptd4-thtkc-vevew-riuws-5wug4-002",
       ];

3. Import the Two Restrictive Methods: The following methods are restricted and can only be accessed by the Cygnus backend canister and whitelisted PrincipalIDs.

   • fetchCanisterStatus method: Use this method to retrive the status of your canister.-

     The auxPrincipalId parameter is used when a user is registering a canister through Candid. Only whitelisted PrincipalIDs can make an Candid call to register a new canister.

     public shared (msg) func fetchCanisterStatus(auxPrincipalId : ?Principal) : async Cygnus.CanisterStatus {
         let cygnusClass = Cygnus.Cygnus();
         cygnusClass.validateUser(msg.caller, auxPrincipalId);
         await cygnusClass.getStatus(Principal.fromActor(Main));
     };

Note: Please replace "Main" with the name of your specific actor in the above line.

• (Optional) approveCycleWithdrawal Method: This method enables the withdrawal of cycles from your canister. Its implementation is optional, but not using this method will result in the inability to withdraw cycles from your canister.-

        public shared (msg) func approveCycleWithdrawal(withdrawAmount : Nat) : async () {
            let cygnusClass = Cygnus.Cygnus();
            cygnusClass.validateUser(msg.caller, null);
            let sendablelimit : Nat = Cycles.balance();
            let sendableCycles = if (withdrawAmount <= sendablelimit) withdrawAmount
              else sendablelimit;
            Cycles.add(sendableCycles);
            await cygnusClass.CygnusCanitser.acceptWithdrwalCyclesFromOtherCanitsers();
        };

Please refer to the Example folder for reference.Make sure to add your own Principal IDs to the whitelistedPrincipalIds array in the Cygnus.mo file.