tokio-migrate

Tokio Migrate Command

This command assists with migrating synchronous code to async Tokio, upgrading between Tokio versions, or converting from other async runtimes.

Arguments

• $1 - Migration type: sync-to-async, tokio-upgrade, runtime-switch (required)
• $2 - Target file or directory (optional, defaults to current directory)
• $3 - Additional context: Tokio version for upgrades, or source runtime for switches (optional)

Usage

/rust-tokio-expert:tokio-migrate sync-to-async src/handlers/
/rust-tokio-expert:tokio-migrate tokio-upgrade src/ 1.0
/rust-tokio-expert:tokio-migrate runtime-switch src/ async-std

Workflow

1. Sync to Async Migration

When migrating synchronous code to async Tokio:

Analysis Phase

1. Scan Target Files

   • Use Glob to find all Rust files in target
   • Read files and identify synchronous operations
   • Detect blocking I/O operations
   • Find CPU-intensive operations
   • Identify thread spawning

2. Identify Conversion Candidates

   • Functions with I/O operations (network, file, database)
   • Functions that spawn threads
   • Functions with sleep/delays
   • Functions with synchronous HTTP clients
   • Functions with blocking mutex operations

3. Analyze Dependencies

   • Check Cargo.toml for sync crates
   • Identify replacements (e.g., reqwest blocking → async)
   • Find database drivers needing async versions

Migration Phase

1. Invoke Agent

   • Use Task tool with subagent_type="rust-tokio-expert:tokio-pro"
   • Provide code context and migration plan

2. Convert Functions to Async

   The agent should transform:

   Synchronous Function:

   use std::fs::File;
   use std::io::Read;
   
   fn read_config(path: &str) -> Result<String, Error> {
       let mut file = File::open(path)?;
       let mut contents = String::new();
       file.read_to_string(&mut contents)?;
       Ok(contents)
   }
   

   To Async:

   use tokio::fs::File;
   use tokio::io::AsyncReadExt;
   
   async fn read_config(path: &str) -> Result<String, Error> {
       let mut file = File::open(path).await?;
       let mut contents = String::new();
       file.read_to_string(&mut contents).await?;
       Ok(contents)
   }