Builders - adding a custom made module

.snippets/code/basic-substrate/lottery-example-calls.rs

@@ -0,0 +1,99 @@
+#[pallet::call]
+impl<T: Config> Pallet<T> {
+
+    #[pallet::call_index(0)]
+    #[pallet::weight(0)]
+    pub fn buy_ticket(origin: OriginFor<T>) -> DispatchResult {
+
+        // 1. Validates the origin signature
+        let buyer = ensure_signed(origin)?;
+
+        // 2. Checks that the user has enough balance to afford the ticket price
+        ensure!(
+            T::Currency::free_balance(&buyer) >= T::TicketCost::get(),
+            Error::<T>::NotEnoughCurrency
+        );
+
+        // 3. Checks that the user is not already participating
+        if let Some(participants) = Self::get_participants() {
+            ensure!(
+                !participants.contains(&buyer),
+                Error::<T>::AccountAlreadyParticipating
+            );
+        }
+
+        // 4. Adds the user as a new participant for the prize
+        match Self::get_participants() {
+            Some(mut participants) => { 
+                ensure!(
+                    participants.try_push(buyer.clone()).is_ok(), 
+                    Error::<T>::CanNotAddParticipant
+                );
+                Participants::<T>::set(Some(participants));
+            }, 
+            None => {
+                let mut participants = BoundedVec::new();
+                ensure!(
+                    participants.try_push(buyer.clone()).is_ok(), 
+                    Error::<T>::CanNotAddParticipant
+                );
+                Participants::<T>::set(Some(participants));
+            }
+        };
+
+        // 5. Transfers the ticket cost to the module's account
+        // to be hold until transferred to the winner
+        T::Currency::transfer(
+            &buyer, 
+            &Self::get_pallet_account(), 
+            T::TicketCost::get(), 
+            ExistenceRequirement::KeepAlive)?;
+
+        // 6. Notify the event
+        Self::deposit_event(Event::TicketBought { who: buyer });
+        Ok(())
+    }
+
+    #[pallet::call_index(1)]
+    #[pallet::weight(0)]
+    pub fn award_prize(origin: OriginFor<T>) -> DispatchResult {
+
+        // 1. Validates the origin signature
+        let _who = ensure_root(origin)?;
+
+        match Self::get_participants() {
+            Some(participants) => { 
+
+                // 2. Gets a random number from the randomness module
+                let nonce = Self::get_and_increment_nonce();
+                let (random_seed, _) = T::MyRandomness::random(&nonce);
+                let random_number = <u32>::decode(&mut random_seed.as_ref())
+                    .expect("secure hashes should always be bigger than u32; qed");
+
+                // 3. Selects the winner from the participants lit
+                let winner_index = random_number as usize % participants.len();
+                let winner = participants.as_slice().get(winner_index).unwrap();
+
+                // 4. Transfers the total prize to the winner's account
+                let prize = T::Currency::free_balance(&Self::get_pallet_account());
+                T::Currency::transfer(
+                    &Self::get_pallet_account(), 
+                    &winner, 
+                    prize, 
+                    ExistenceRequirement::AllowDeath)?;
+
+                // 5. Resets the participants list, and gets ready for another lottery round
+                Participants::<T>::kill();
+
+                // 6. Notify the event
+                Self::deposit_event(Event::PrizeAwarded { winner: winner.clone() } );
+            }, 
+            None => {
+                // Notify the event (No participants)
+                Self::deposit_event(Event::ThereAreNoParticipants);
+            }
+        };
+
+        Ok(())
+    }
+}

.snippets/code/basic-substrate/lottery-example-cargo.toml

@@ -0,0 +1,53 @@
+[package]
+name = "module-lottery-example"
+version = "4.0.0-dev"
+description = "Simple module example"
+authors = [""]
+homepage = ""
+edition = "2021"
+publish = false
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.6.1", default-features = false, features = [
+	"derive",
+] }
+scale-info = { version = "2.5.0", default-features = false, features = ["derive"] }
+frame-benchmarking = { 
+	version = "4.0.0-dev", 
+	default-features = false, 
+	optional = true, 
+	git = "https://github.com/paritytech/substrate.git", 
+	branch = "polkadot-v1.0.0" 
+}
+frame-support = { 
+	version = "4.0.0-dev", 
+	default-features = false, 
+	git = "https://github.com/paritytech/substrate.git", 
+	branch = "polkadot-v1.0.0" 
+}
+frame-system = { 
+	version = "4.0.0-dev", 
+	default-features = false, 
+	git = "https://github.com/paritytech/substrate.git", 
+	branch = "polkadot-v1.0.0" 
+}
+
+[dev-dependencies]
+sp-core = { version = "21.0.0", git = "https://github.com/paritytech/substrate.git", branch = "polkadot-v1.0.0" }
+sp-io = { version = "23.0.0", git = "https://github.com/paritytech/substrate.git", branch = "polkadot-v1.0.0" }
+sp-runtime = { version = "24.0.0", git = "https://github.com/paritytech/substrate.git", branch = "polkadot-v1.0.0" }
+
+[features]
+default = ["std"]
+std = [
+	"codec/std",
+	"frame-benchmarking?/std",
+	"frame-support/std",
+	"frame-system/std",
+	"scale-info/std",
+]
+runtime-benchmarks = ["frame-benchmarking/runtime-benchmarks"]
+try-runtime = ["frame-support/try-runtime"]

.snippets/code/modules/lottery-example.rs

@@ -21,7 +21,8 @@ pub mod pallet {
 		PalletId,
 	};
 
-	type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
+	type BalanceOf<T> = 
+		<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
 
 	#[pallet::pallet]
 	pub struct Pallet<T>(_);
@@ -30,23 +31,27 @@ pub mod pallet {
 	#[pallet::config]
 	pub trait Config: frame_system::Config {
 
-		/// Because this pallet emits events, it depends on the runtime's definition of an event.
-		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
+		// 1. Event definition
+		type RuntimeEvent: From<Event<Self>> 
+			+ IsType<<Self as frame_system::Config>::RuntimeEvent>;
 
-        /// This module depends on other modules, such as balances and randomness
+		// 2. Currency 
 		type Currency: Currency<Self::AccountId> 
 			+ ReservableCurrency<Self::AccountId>
 			+ LockableCurrency<Self::AccountId>;
 
+		// 3. Randomness
 		type MyRandomness: Randomness<Self::Hash, BlockNumberFor<Self>>;
 
-        /// Some values that must be configured when adding the module to the runtime
+		// 4. Ticket cost
 		#[pallet::constant]
 		type TicketCost: Get<BalanceOf<Self>>;
 
+		// 5. Maximum number of participants
 		#[pallet::constant]
 		type MaxParticipants: Get<u32>;
 
+		// 6. Module Id
 		#[pallet::constant]
 		type PalletId: Get<PalletId>;
 	}
@@ -91,27 +96,29 @@ pub mod pallet {
 
 	#[pallet::call]
 	impl<T: Config> Pallet<T> {
-		
+
 		#[pallet::call_index(0)]
 		#[pallet::weight(0)]
 		pub fn buy_ticket(origin: OriginFor<T>) -> DispatchResult {
+
+			// 1. Validates the origin signature
 			let buyer = ensure_signed(origin)?;
 
-			// Checks that the user has enough balance to afford the ticket price
+			// 2. Checks that the user has enough balance to afford the ticket price
 			ensure!(
 				T::Currency::free_balance(&buyer) >= T::TicketCost::get(),
 				Error::<T>::NotEnoughCurrency
 			);
 
-			// Checks that the user do not have a ticket yet
+			// 3. Checks that the user is not already participating
 			if let Some(participants) = Self::get_participants() {
 				ensure!(
 					!participants.contains(&buyer),
 					Error::<T>::AccountAlreadyParticipating
 				);
 			}
 
-            // Stores the user to participate in the lottery
+			// 4. Adds the user as a new participant for the prize
 			match Self::get_participants() {
 				Some(mut participants) => { 
 					ensure!(
@@ -130,42 +137,55 @@ pub mod pallet {
 				}
 			};
 
-            // Transfer the ticket cost to the module's account
-			T::Currency::transfer(&buyer, &Self::get_pallet_account(), T::TicketCost::get(), ExistenceRequirement::KeepAlive)?;
+			// 5. Transfers the ticket cost to the module's account
+			// to be hold until transferred to the winner
+			T::Currency::transfer(
+				&buyer, 
+				&Self::get_pallet_account(), 
+				T::TicketCost::get(), 
+				ExistenceRequirement::KeepAlive)?;
 
-            // Notify the event
+			// 6. Notify the event
 			Self::deposit_event(Event::TicketBought { who: buyer });
 			Ok(())
 		}
 
 		#[pallet::call_index(1)]
 		#[pallet::weight(0)]
 		pub fn award_prize(origin: OriginFor<T>) -> DispatchResult {
+
+			// 1. Validates the origin signature
 			let _who = ensure_root(origin)?;
 
 			match Self::get_participants() {
 				Some(participants) => { 
 
-                    // Gets a random number, using randomness module
+					// 2. Gets a random number from the randomness module
 					let nonce = Self::get_and_increment_nonce();
 					let (random_seed, _) = T::MyRandomness::random(&nonce);
 					let random_number = <u32>::decode(&mut random_seed.as_ref())
 						.expect("secure hashes should always be bigger than u32; qed");
 
-                    // Selects the winner 
+					// 3. Selects the winner from the participants lit
 					let winner_index = random_number as usize % participants.len();
 					let winner = participants.as_slice().get(winner_index).unwrap();
 
-                    // Transfers the total prize to the winner's account
+					// 4. Transfers the total prize to the winner's account
 					let prize = T::Currency::free_balance(&Self::get_pallet_account());
-					T::Currency::transfer(&Self::get_pallet_account(), &winner, prize, ExistenceRequirement::AllowDeath)?;
+					T::Currency::transfer(
+						&Self::get_pallet_account(), 
+						&winner, 
+						prize, 
+						ExistenceRequirement::AllowDeath)?;
 
-                    // Resets the storage, and gets ready for another lottery round
+					// 5. Resets the participants list, and gets ready for another lottery round
 					Participants::<T>::kill();
 
+					// 6. Notify the event
 					Self::deposit_event(Event::PrizeAwarded { winner: winner.clone() } );
 				}, 
 				None => {
+					// Notify the event (No participants)
 					Self::deposit_event(Event::ThereAreNoParticipants);
 				}
 			};

builders/build/.pages

@@ -3,7 +3,7 @@ hide: false
 nav:
   - index.md
   - 'Prerequisites': 'prerequisites.md'
-  # - 'Basic Substrate': 'substrate.md'
+  - 'substrate'
   # - 'Templates': 'templates.md'
   # - 'Modifying your ContainerChain': 'modifying.md'
   # - 'Test Locally': 'test.md'

builders/build/substrate/.pages

@@ -0,0 +1,5 @@
+title: Basic Substrate
+hide: false
+nav:
+  - index.md
+  - 'Adding a Custom-Made Module': 'adding-custom-made-module.md'