Rust Training — Microsoft

Package Management: Cargo vs NuGet

What you'll learn: Cargo.toml vs .csproj, version specifiers, Cargo.lock, feature flags for conditional compilation, and common Cargo commands mapped to their NuGet/dotnet equivalents.

Difficulty: 🟢 Beginner

Dependency Declaration

C# NuGet Dependencies

<!-- MyApp.csproj -->
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
  </PropertyGroup>
  
  <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
  <PackageReference Include="Serilog" Version="3.0.1" />
  <PackageReference Include="Microsoft.AspNetCore.App" />
  
  <ProjectReference Include="../MyLibrary/MyLibrary.csproj" />
</Project>

Rust Cargo Dependencies

# Cargo.toml
[package]
name = "my_app"
version = "0.1.0"
edition = "2021"

[dependencies]
serde_json = "1.0"               # From crates.io (like NuGet)
serde = { version = "1.0", features = ["derive"] }  # With features
log = "0.4"
tokio = { version = "1.0", features = ["full"] }

# Local dependencies (like ProjectReference)
my_library = { path = "../my_library" }

# Git dependencies
my_git_crate = { git = "https://github.com/user/repo" }

# Development dependencies (like test packages)
[dev-dependencies]
criterion = "0.5"               # Benchmarking
proptest = "1.0"               # Property testing

Version Management

C# Package Versioning

<!-- Centralized package management (Directory.Packages.props) -->
<Project>
  <PropertyGroup>
    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
  </PropertyGroup>
  
  <PackageVersion Include="Newtonsoft.Json" Version="13.0.3" />
  <PackageVersion Include="Serilog" Version="3.0.1" />
</Project>

<!-- packages.lock.json for reproducible builds -->

Rust Version Management

# Cargo.toml - Semantic versioning
[dependencies]
serde = "1.0"        # Compatible with 1.x.x (>=1.0.0, <2.0.0)
log = "0.4.17"       # Compatible with 0.4.x (>=0.4.17, <0.5.0)
regex = "=1.5.4"     # Exact version
chrono = "^0.4"      # Caret requirements (default)
uuid = "~1.3.0"      # Tilde requirements (>=1.3.0, <1.4.0)

# Cargo.lock - Exact versions for reproducible builds (auto-generated)
[[package]]
name = "serde"
version = "1.0.163"
# ... exact dependency tree

Package Sources

C# Package Sources

<!-- nuget.config -->
<configuration>
  <packageSources>
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
    <add key="MyCompanyFeed" value="https://pkgs.dev.azure.com/company/_packaging/feed/nuget/v3/index.json" />
  </packageSources>
</configuration>

Rust Package Sources

# .cargo/config.toml
[source.crates-io]
replace-with = "my-awesome-registry"

[source.my-awesome-registry]
registry = "https://my-intranet:8080/index"

# Alternative registries
[registries]
my-registry = { index = "https://my-intranet:8080/index" }

# In Cargo.toml
[dependencies]
my_crate = { version = "1.0", registry = "my-registry" }

Common Commands Comparison

Task	C# Command	Rust Command
Restore packages	`dotnet restore`	`cargo fetch`
Add package	`dotnet add package Newtonsoft.Json`	`cargo add serde_json`
Remove package	`dotnet remove package Newtonsoft.Json`	`cargo remove serde_json`
Update packages	`dotnet update`	`cargo update`
List packages	`dotnet list package`	`cargo tree`
Audit security	`dotnet list package --vulnerable`	`cargo audit`
Clean build	`dotnet clean`	`cargo clean`

Features: Conditional Compilation

C# Conditional Compilation

#if DEBUG
    Console.WriteLine("Debug mode");
#elif RELEASE
    Console.WriteLine("Release mode");
#endif

// Project file features
<PropertyGroup Condition="'$(Configuration)'=='Debug'">
    <DefineConstants>DEBUG;TRACE</DefineConstants>
</PropertyGroup>

Rust Feature Gates

# Cargo.toml
[features]
default = ["json"]              # Default features
json = ["serde_json"]          # Feature that enables serde_json
xml = ["serde_xml"]            # Alternative serialization
advanced = ["json", "xml"]     # Composite feature

[dependencies]
serde_json = { version = "1.0", optional = true }
serde_xml = { version = "0.4", optional = true }

// Conditional compilation based on features
#[cfg(feature = "json")]
use serde_json;

#[cfg(feature = "xml")]
use serde_xml;

pub fn serialize_data(data: &MyStruct) -> String {
    #[cfg(feature = "json")]
    return serde_json::to_string(data).unwrap();
    
    #[cfg(feature = "xml")]
    return serde_xml::to_string(data).unwrap();
    
    #[cfg(not(any(feature = "json", feature = "xml")))]
    return "No serialization feature enabled".to_string();
}

Using External Crates

Popular Crates for C# Developers

C# Library	Rust Crate	Purpose
Newtonsoft.Json	`serde_json`	JSON serialization
HttpClient	`reqwest`	HTTP client
Entity Framework	`diesel` / `sqlx`	ORM / SQL toolkit
NLog/Serilog	`log` + `env_logger`	Logging
xUnit/NUnit	Built-in `#[test]`	Unit testing
Moq	`mockall`	Mocking
Flurl	`url`	URL manipulation
Polly	`tower`	Resilience patterns

Example: HTTP Client Migration

// C# HttpClient usage
public class ApiClient
{
    private readonly HttpClient _httpClient;
    
    public async Task<User> GetUserAsync(int id)
    {
        var response = await _httpClient.GetAsync($"/users/{id}");
        var json = await response.Content.ReadAsStringAsync();
        return JsonConvert.DeserializeObject<User>(json);
    }
}

// Rust reqwest usage
use reqwest;
use serde::Deserialize;

#[derive(Deserialize)]
struct User {
    id: u32,
    name: String,
}

struct ApiClient {
    client: reqwest::Client,
}

impl ApiClient {
    async fn get_user(&self, id: u32) -> Result<User, reqwest::Error> {
        let user = self.client
            .get(&format!("https://api.example.com/users/{}", id))
            .send()
            .await?
            .json::<User>()
            .await?;
        
        Ok(user)
    }
}