add demo for CPI

chapters/03_anchor.md

@@ -51,7 +51,7 @@ anchor --version
 * An Anchor program consists of three parts:
   - The `program` module: where the logic is written.
   - The account structs, marked with `#[derive(Accounts)]`, where accounts are validated.
-  - The `declare_id` macro, which creates an `ID` field to store the address of the program.
+  - The `declare_id` macro, creates an `ID` field to store the address of the program.
 
 <br>
 
@@ -61,7 +61,7 @@ anchor --version
 
 <br>
 
-* Where you define the business logic, by writing functions that can be called by clietns or other programs.
+* Where you define the business logic by writing functions that clients or other programs can call:
 
 ```rust
 #[program]
@@ -80,20 +80,20 @@ mod hello_anchor {
 
 * Each endpoint takes a `Context` type as its first argument, so it can access:
     - the accounts (`ctx.accounts`)
-    - the program_id (`ctx.program_id`) of the executing programs
-    -  remaining accounts (`ctx.remaining_accounts`)
+    - the program_id (`ctx.program_id`) of the executing program
+    - remaining accounts (`ctx.remaining_accounts`)
 
 <br>
 
-* If a function requires instruction data, they can be added through arguments to the function after the context argument.
+* If a function requires instruction data, it can be added through arguments to the function after the context argument.
 
 <br>
 
 #### The Accounts Struct
 
 <br>
 
-* Define which accounts a instruction expects, and their constraints.
+* Define which accounts an instruction expects, and their constraints.
 
 * There are two constructs:
     - `Types`: have a specific use case.
@@ -120,7 +120,7 @@ pub struct SetData<'info> {
 
 <br>
 
-* Account types are not dynamic enough to handle all the security checks that the program requires
+* Account types are not dynamic enough to handle all the security checks that the program requires.
 
 * Constraints can be added through:
 
@@ -140,7 +140,7 @@ pub account: AccountType
     - `AnchorErrors`: divided into anchor internal errors and custom errors
     - non-anchor errors
 
-* You can use the `require` macro to simplify writting errors.
+* You can use the `require` macro to simplify writing errors.
 
 ```rust
 #[program]

demos/01_hello_world/.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

demos/02_anchor_cpi/README.md

@@ -1 +1,276 @@
-# 🛹 Anchor and the Interface Definition Language [IN CONSTRUCTION]
+# 🛹 Demo 2: Anchor and Cross-Program Invocations
+
+<br>
+
+
+### Program 1: "Puppet"
+
+<br> 
+
+* To show how CPI works, let's create a simple program called puppet. You can use this demo or run `anchor init puppet`.
+
+* Inside `src/lib.rs`, we write the following:
+
+<br>
+
+
+```rust
+use anchor_lang::prelude::*;
+
+declare_id!("<some string>");
+
+#[program]
+pub mod puppet {
+    use super::*;
+    pub fn initialize(_ctx: Context<Initialize>) -> Result<()> {
+        Ok(())
+    }
+
+    pub fn set_data(ctx: Context<SetData>, data: u64) -> Result<()> {
+        let puppet = &mut ctx.accounts.puppet;
+        puppet.data = data;
+        Ok(())
+    }
+}
+
+#[derive(Accounts)]
+pub struct Initialize<'info> {
+    #[account(init, payer = user, space = 8 + 8)]
+    pub puppet: Account<'info, Data>,
+    #[account(mut)]
+    pub user: Signer<'info>,
+    pub system_program: Program<'info, System>,
+}
+
+#[derive(Accounts)]
+pub struct SetData<'info> {
+    #[account(mut)]
+    pub puppet: Account<'info, Data>,
+}
+
+#[account]
+pub struct Data {
+    pub data: u64,
+}
+```
+
+<br>
+
+* Build the program with:
+
+<br>
+
+```
+anchor build
+```
+
+<br>
+
+---
+
+### Program 2: "Puppet-Master"
+
+<br>
+
+* Let's create a second program called puppet-master, and write the following inside `src/lib.rs`:
+
+<br>
+
+```rust
+use anchor_lang::prelude::*;
+use puppet::cpi::accounts::SetData;
+use puppet::program::Puppet;
+use puppet::{self, Data};
+
+declare_id!("<another string>");
+
+#[program]
+mod puppet_master {
+    use super::*;
+    pub fn pull_strings(ctx: Context<PullStrings>, data: u64) -> Result<()> {
+        let cpi_program = ctx.accounts.puppet_program.to_account_info();
+        let cpi_accounts = SetData {
+            puppet: ctx.accounts.puppet.to_account_info(),
+        };
+        let cpi_ctx = CpiContext::new(cpi_program, cpi_accounts);
+        puppet::cpi::set_data(cpi_ctx, data)
+    }
+}
+
+#[derive(Accounts)]
+pub struct PullStrings<'info> {
+    #[account(mut)]
+    pub puppet: Account<'info, Data>,
+    pub puppet_program: Program<'info, Puppet>,
+}
+```
+
+<br>
+
+* To make it work,  add the following inside the program's `Cargo.toml`:
+
+
+<br>
+
+```yaml
+[package]
+name = "puppet-master"
+version = "0.1.0"
+description = "Created with Anchor"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "puppet_master"
+
+[features]
+no-entrypoint = []
+no-idl = []
+no-log-ix-name = []
+cpi = ["no-entrypoint"]
+default = []
+
+[dependencies]
+anchor-lang = "0.29.0"
+puppet = { path = "../../../puppet/programs/puppet", features = ["cpi"]}
+
+```
+
+<br>
+
+* Build the program with:
+
+```
+anchor build
+```
+
+<br>
+
+
+---
+
+### Explanation
+
+<br>
+
+* Inside the puppet program, puppet-master uses the `SetData` instruction builder `struct` provided by the `puppet::cpi::accounts` module to submit the accounts the `SetData` instruction of the puppet program expects. 
+
+* This means that puppet-master creates a new cpi context and passes it to the `puppet::cpi::set_data` cpi function. 
+
+* This function has the exact same function as the `set_data` function in the puppet program with the exception that it expects a `CpiContext` instead of a `Context`.
+
+<br>
+
+
+---
+
+### Testing
+
+<br>
+
+* Test the program with this file inside `puppet-master/test/puppet-master.ts`:
+
+<br>
+
+```typescript
+import * as anchor from "@coral-xyz/anchor";
+import { Program } from "@coral-xyz/anchor";
+import { Keypair } from "@solana/web3.js";
+import { expect } from "chai";
+import { Puppet } from "../target/types/puppet";
+import { PuppetMaster } from "../target/types/puppet_master";
+
+describe("puppet", () => {
+  const provider = anchor.AnchorProvider.env();
+  anchor.setProvider(provider);
+
+  const puppetProgram = anchor.workspace.Puppet as Program<Puppet>;
+  const puppetMasterProgram = anchor.workspace
+    .PuppetMaster as Program<PuppetMaster>;
+
+  const puppetKeypair = Keypair.generate();
+
+  it("Does CPI!", async () => {
+    await puppetProgram.methods
+      .initialize()
+      .accounts({
+        puppet: puppetKeypair.publicKey,
+        user: provider.wallet.publicKey,
+      })
+      .signers([puppetKeypair])
+      .rpc();
+
+    await puppetMasterProgram.methods
+      .pullStrings(new anchor.BN(42))
+      .accounts({
+        puppetProgram: puppetProgram.programId,
+        puppet: puppetKeypair.publicKey,
+      })
+      .rpc();
+
+    expect(
+      (
+        await puppetProgram.account.data.fetch(puppetKeypair.publicKey)
+      ).data.toNumber()
+    ).to.equal(42);
+  });
+});
+```
+
+<br>
+
+* Running:
+
+<br>
+
+```shell
+cargo test
+```
+
+<br>
+
+----
+
+### Improvements
+
+<br>
+
+* It's recommended to move the CPI setup into the `impl` block of the instruction. The puppet-master program then looks like this:
+
+<br>
+
+```rust
+use anchor_lang::prelude::*;
+use puppet::cpi::accounts::SetData;
+use puppet::program::Puppet;
+use puppet::{self, Data};
+
+declare_id!("HmbTLCmaGvZhKnn1Zfa1JVnp7vkMV4DYVxPLWBVoN65L");
+
+#[program]
+mod puppet_master {
+    use super::*;
+    pub fn pull_strings(ctx: Context<PullStrings>, data: u64) -> Result<()> {
+        puppet::cpi::set_data(ctx.accounts.set_data_ctx(), data)
+    }
+}
+
+#[derive(Accounts)]
+pub struct PullStrings<'info> {
+    #[account(mut)]
+    pub puppet: Account<'info, Data>,
+    pub puppet_program: Program<'info, Puppet>,
+}
+
+
+impl<'info> PullStrings<'info> {
+    pub fn set_data_ctx(&self) -> CpiContext<'_, '_, '_, 'info, SetData<'info>> {
+        let cpi_program = self.puppet_program.to_account_info();
+        let cpi_accounts = SetData {
+            puppet: self.puppet.to_account_info()
+        };
+        CpiContext::new(cpi_program, cpi_accounts)
+    }
+}
+```
+

demos/02_anchor_cpi/puppet-master/.gitignore

@@ -0,0 +1,7 @@
+.anchor
+.DS_Store
+target
+**/*.rs.bk
+node_modules
+test-ledger
+.yarn

demos/02_anchor_cpi/puppet-master/Anchor.toml

@@ -0,0 +1,18 @@
+[toolchain]
+
+[features]
+seeds = false
+skip-lint = false
+
+[programs.localnet]
+puppet_master = "DrL7fRZQKqF7GQuvzxYe4K6MV4inzodj8dhr1PPV8Fqr"
+
+[registry]
+url = "https://api.apr.dev"
+
+[provider]
+cluster = "Localnet"
+wallet = "/Users/m/.config/solana/id.json"
+
+[scripts]
+test = "yarn run ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts"