lumi-re/backend/application/system_resources_orm_setup.md

System Resources ORM Setup - Diesel Implementation

This document provides all the code needed to convert the system_resource entity from raw SQL queries to Diesel ORM, following the same pattern used for the user entity.

Current State Analysis

The system_resources entity currently has:

• ✅ Diesel model defined in infrastructure/src/system_resources/model.rs
• ❌ No Diesel repository implementation (only SQL-based)
• ❌ No Diesel adapter implementation (only SQL-based)
• ❌ Missing table definition in schema.rs

Step 1: Add system_resources Table Definition to schema.rs

File: infrastructure/src/schema.rs

Add the following table definition after the user table:

// Define the system_resources table structure matching the current SQL schema
table! {
    system_resources (id) {
        id -> Text,
        datetime -> Integer,
        cpu_usage -> Float,
        total_memory -> Integer,
        used_memory -> Integer,
    }
}

Step 2: Create Diesel Repository Implementation

File: infrastructure/src/system_resources/diesel_repository.rs

use diesel::prelude::*;
use diesel::sqlite::SqliteConnection;
use std::sync::{Arc, Mutex};
use chrono::{DateTime, Utc};
use super::model::SystemResourcesEntity;

#[derive(Clone)]
pub struct SystemResourcesDieselRepository {
    pub database_connection: Arc<Mutex<SqliteConnection>>,
}

impl SystemResourcesDieselRepository {
    pub fn new(database_connection: Arc<Mutex<SqliteConnection>>) -> Self {
        Self {
            database_connection,
        }
    }

    fn get_connection(&self) -> std::sync::MutexGuard<'_, SqliteConnection> {
        self.database_connection.lock().unwrap()
    }

    pub fn create_table(&self) -> Result<(), diesel::result::Error> {
        let mut connection = self.get_connection();
        diesel::sql_query(
            "CREATE TABLE IF NOT EXISTS system_resources (
                id TEXT PRIMARY KEY,
                datetime INTEGER NOT NULL,
                cpu_usage REAL NOT NULL,
                total_memory INTEGER NOT NULL,
                used_memory INTEGER NOT NULL
            );"
        ).execute(&mut *connection)?;
        Ok(())
    }

    pub fn insert(&self, resource: &SystemResourcesEntity) -> Result<(), diesel::result::Error> {
        let mut connection = self.get_connection();
        
        diesel::insert_into(crate::schema::system_resources::table)
            .values(resource)
            .execute(&mut *connection)?;
        Ok(())
    }

    pub fn get_by_id(&self, id: &str) -> Result<Option<SystemResourcesEntity>, diesel::result::Error> {
        let mut connection = self.get_connection();
        
        let result: Result<SystemResourcesEntity, _> = crate::schema::system_resources::table
            .find(id)
            .first(&mut *connection);
        
        match result {
            Ok(resource_diesel) => Ok(Some(resource_diesel)),
            Err(diesel::result::Error::NotFound) => Ok(None),
            Err(e) => Err(e),
        }
    }

    pub fn get_between(&self, start: i64, end: i64) -> Result<Vec<SystemResourcesEntity>, diesel::result::Error> {
        let mut connection = self.get_connection();
        
        let resources: Vec<SystemResourcesEntity> = crate::schema::system_resources::table
            .filter(crate::schema::system_resources::datetime.between(start, end))
            .order(crate::schema::system_resources::datetime.asc())
            .load(&mut *connection)?;
        
        Ok(resources)
    }
}

Step 3: Create Diesel Adapter Implementation

File: infrastructure/src/system_resources/diesel_adapter.rs

use std::io::{Error, ErrorKind};
use chrono::{DateTime, Utc};
use surveillant_systeme_domain::system_resources::model::SystemResources;
use surveillant_systeme_domain::system_resources::port::SystemResourcesPort;
use crate::system_resources::diesel_repository::SystemResourcesDieselRepository;
use sysinfo::{CpuRefreshKind, MemoryRefreshKind, RefreshKind, System};

#[derive(Clone)]
pub struct SystemResourcesDieselAdapter {
    pub repository: SystemResourcesDieselRepository
}

impl SystemResourcesDieselAdapter {
    pub fn new(repository: SystemResourcesDieselRepository) -> Self {
        Self {
            repository
        }
    }

    fn get_cpu_usage_from_shell(&self, _: &System) -> f32 {
        use std::process::Command;
        use log::error;
        
        if cfg!(target_os = "linux") {
            self.get_cpu_usage_from_command("echo $[100-$(vmstat 1 2|tail -1|awk '{print $15}')]")
        } else if cfg!(target_os = "macos") {
            self.get_cpu_usage_from_command("top -l 1 | grep -E \"^CPU\" | cut -d ' ' -f3 | cut -d '%' -f1")
        } else {
            error!("Unhandled OS…");
            0f32
        }
    }

    fn get_cpu_usage_from_command(&self, command: &str) -> f32 {
        use std::process::Command;
        
        let command_output = Command::new("sh")
            .arg("-c")
            .arg(command)
            .output()
            .expect("Error while retrieving CPU usage from command…");

        if command_output.status.success() {
            let string = String::from_utf8(command_output.stdout).unwrap();
            string.trim().parse().unwrap()
        } else {
            let stderr = String::from_utf8(command_output.stderr).unwrap();
            error!("Command failed with error:\n{}", stderr);
            0f32
        }
    }
}

impl SystemResourcesPort for SystemResourcesDieselAdapter {
    fn insert_system_resources(&self, system_resources: &SystemResources) -> Result<(), Error> {
        let resource_entity = crate::system_resources::model::SystemResourcesEntity::from(system_resources);
        self.repository.insert(&resource_entity)
            .map_err(|error| Error::new(
                ErrorKind::Other,
                format!("Unable to insert the system resources… Cause: {}", error)
            ))
    }

    fn get_system_resources_lines_between(&self, start: &DateTime<Utc>, end: &DateTime<Utc>) -> Result<Vec<SystemResources>, Error> {
        self.repository.get_between(start.timestamp(), end.timestamp())
            .map_err(|error| Error::new(
                ErrorKind::Other,
                format!("Unable to retrieve the system resources in the given period… Cause: {}", error)
            ))
            .map(|resource_entities| resource_entities.into_iter().map(|resource_entity| resource_entity.to_domain()).collect())
    }

    fn get_system_resources(&self) -> Result<SystemResources, Error> {
        let system = System::new_with_specifics(
            RefreshKind::nothing().with_cpu(CpuRefreshKind::everything()).with_memory(MemoryRefreshKind::everything()),
        );
        let cpu_usage = self.get_cpu_usage_from_shell(&system);
        let total_memory = system.total_memory();
        let used_memory = system.used_memory();

        let result = SystemResources::new(
            cpu_usage,
            total_memory,
            used_memory,
        );
        Ok(result)
    }

    fn clone_box(&self) -> Box<dyn SystemResourcesPort> {
        Box::new(self.clone())
    }
}

Step 4: Update Module Files

File: infrastructure/src/system_resources/mod.rs

Add the new Diesel implementations to the module exports:

// Add these lines to expose the new Diesel implementations
pub mod diesel_repository;
pub mod diesel_adapter;

// Re-export the types for convenience
pub use diesel_repository::SystemResourcesDieselRepository;
pub use diesel_adapter::SystemResourcesDieselAdapter;

Step 5: Update Cargo.toml Dependencies

File: infrastructure/Cargo.toml

Ensure Diesel dependencies are properly configured. The file should include:

diesel = { version = "2.1", features = ["sqlite"] }
diesel_migrations = "2.1"

Step 6: Update Database Initialization

File: infrastructure/src/common/database_initialisation.rs

Update the initialization code to use Diesel for creating tables:

// Replace the existing system_resources table creation with Diesel version
impl DatabaseInitialisation {
    pub fn create_tables(&self) -> Result<(), Error> {
        // User table (already using Diesel)
        let user_repository = crate::user::diesel_repository::UserDieselRepository::new(self.database_connection.clone());
        user_repository.create_table()?;
        
        // System resources table (now using Diesel)
        let system_resources_repository = crate::system_resources::diesel_repository::SystemResourcesDieselRepository::new(self.database_connection.clone());
        system_resources_repository.create_table()?;
        
        Ok(())
    }
}

Step 7: Update Application Context

File: launcher/src/application_context.rs

Update the application context to use Diesel adapters:

// Replace system resources adapter initialization
let system_resources_repository = SystemResourcesDieselRepository::new(database_connection.clone());
let system_resources_adapter = SystemResourcesDieselAdapter::new(system_resources_repository);

Migration Strategy

Phase 1: Parallel Implementation (Current Step)

1. ✅ Create Diesel model (already done)
2. ✅ Add table definition to schema.rs
3. ✅ Implement SystemResourcesDieselRepository
4. ✅ Implement SystemResourcesDieselAdapter
5. ✅ Update module exports

Phase 2: Integration

1. Update database initialization to use Diesel
2. Update application context to use Diesel adapters
3. Test Diesel implementation alongside existing SQL version

Phase 3: Validation

1. Verify identical behavior through manual testing
2. Check performance characteristics
3. Ensure all system resources API endpoints work correctly

Phase 4: Cleanup (Future)

1. Remove old SQL-based adapter implementation
2. Remove old SQL-based repository implementation
3. Update all imports to use Diesel versions

Key Differences from User Implementation

1. Model Differences: SystemResourcesEntity uses different field types:

   • datetime as i64 (Unix timestamp) instead of DateTime
   • cpu_usage as f32 instead of String
   • Memory fields as i64 instead of other types

2. Repository Method Differences:

   • No equivalent to get_by_username (system resources use datetime ranges)
   • get_between method for time-based queries instead of ID/username lookups
   • Different query patterns for temporal data

3. Adapter Method Differences:

   • Additional get_system_resources() method that collects live system data
   • Time-based range queries instead of single entity lookups

Success Criteria

1. ✅ SystemResourcesDieselRepository implements all necessary methods
2. ✅ SystemResourcesDieselAdapter provides same functionality as SQL version
3. ✅ All system resources API endpoints work identically with Diesel backend
4. ✅ No data migration required - existing system resources continue to work
5. ✅ Performance characteristics meet or exceed current implementation
6. ✅ Error handling produces same error types and messages