The issue arises because the two microservices, doctors and hospitals, have separate authentication systems and don’t share a session or token. When navigating between the two services, your login session for one service is invalidated because it’s not recognized by the other.

Here are a few solutions to resolve this issue and ensure a seamless login experience across both microservices:

1. Use a Centralized Authentication System

Implement a single sign-on (SSO) solution to unify authentication across both microservices. SSO allows users to log in once and access multiple related services without needing to log in again.

Steps to Implement:

1. Choose an Identity Provider (IdP): Use a tool like Keycloak, Okta, Auth0, or a custom OAuth 2.0/OpenID Connect-based provider.
2. Integrate Both Services: Update both microservices to delegate authentication to the centralized IdP.
   • Redirect users to the IdP for login.
   • The IdP issues a token (e.g., JWT) that both microservices trust.
3. Share the Token: After login, each service validates the shared token and creates a local session.

Benefits:

• Centralized user management.
• Simplifies user experience with a single login.
• Secure and scalable.

2. Share the Session Across Microservices

If you prefer to keep separate login systems, you can share the session storage between microservices.

Methods to Share Sessions:

1. Centralized Session Store:
   • Use a distributed session storage system (e.g., Redis, Memcached) that both services access.
   • Store session IDs in a shared database or cache.
   Example:
   • Login on the hospitals service creates a session ID stored in Redis.
   • When the doctors service receives a request, it looks up the session ID in the shared Redis store to validate the user.
2. Set a Shared Cookie Domain:
   • Configure the session cookies to use the same root domain, e.g., .myhospitalnow.com.
   • Ensure both microservices issue cookies with the Domain=.myhospitalnow.com attribute.
   Example: Set-Cookie: session_id=abc123; Domain=.myhospitalnow.com; Path=/; HttpOnly This allows both microservices to share the same session cookies.

3. Use Token-Based Authentication

Replace session-based authentication with token-based authentication (e.g., JWT). Tokens can be shared across microservices without requiring shared storage.

Steps:

1. After login, issue a JWT signed with a shared secret or private key.
2. Include the token in requests (e.g., via the Authorization header or cookies).
3. Both services verify the token using the shared key. Example: Authorization: Bearer eyJhbGciOiJIUzI1NiIsIn...

Benefits:

• Stateless and scalable.
• No need for shared session storage.

4. Proxy Authentication Through an API Gateway

Use an API Gateway (e.g., Kong, Traefik, AWS API Gateway) to manage authentication for both microservices.

How It Works:

1. The API Gateway acts as a reverse proxy for both microservices.
2. Authenticate users at the gateway level and issue a token or set a session.
3. The gateway forwards authenticated requests to the respective microservice.

5. Synchronize Sessions Between Services

If you cannot centralize authentication, synchronize session data between the two services.

Steps:

1. After login on one service, send the session/token to the other service via API.
2. The second service validates and creates its own session based on the received data.

Example Workflow:

• User logs into hospitals.
• The hospitals service sends an API request to doctors with the session/token.
• The doctors service validates the token and sets up its session.

6. Cross-Origin Resource Sharing (CORS)

If your microservices are hosted on subdomains (e.g., hospitals.myhospitalnow.com and doctors.myhospitalnow.com), ensure proper CORS settings for seamless communication between services.

Steps:

• Configure the Access-Control-Allow-Origin header in both microservices to allow requests from .myhospitalnow.com.

Best Solution: SSO

If possible, implement a centralized authentication system (SSO) for a scalable and user-friendly experience. For quick fixes, sharing sessions via cookies or a centralized store works well but is less scalable.

Let me know if you need help implementing any of these solutions!

Since both microservices are built with Laravel and are running on the same server, the best approach depends on your long-term goals, complexity tolerance, and scalability needs. Let’s analyze each option based on your setup and recommend the most suitable solution.

1. Use a Centralized Authentication System

This approach involves implementing Single Sign-On (SSO) using a centralized authentication provider like Laravel Passport, Laravel Sanctum, or a third-party Identity Provider (IdP) (e.g., Keycloak, Auth0).

Pros:

• Scalable: Ideal for scenarios where new microservices may be added in the future.
• Secure: Tokens or session validation is centralized, minimizing risks of session hijacking.
• Streamlined User Experience: Users log in once and access all services seamlessly.
• Independent Microservices: Each service can remain independent in terms of session handling, as authentication is handled by the centralized system.

Cons:

• Implementation Overhead: Setting up an IdP or integrating with one requires time and effort.
• Complexity: Adds complexity if you have limited future scalability requirements.

Best Use Case:

• Recommended if you plan to scale your application by adding more microservices in the future.
• Suitable for multi-tenant or large-scale systems.

2. Share the Session Across Microservices

This approach involves sharing the session storage (e.g., Redis or database) between the two microservices or configuring cookies to work across both services.

How It Works with Laravel:

1. Use a shared session driver like Redis:
   • Configure both microservices to use the same Redis session storage: SESSION_DRIVER=redis SESSION_CONNECTION=default SESSION_DOMAIN=.myhospitalnow.com
2. Set cookies to work across both services:
   • Configure SESSION_DOMAIN in config/session.php for both services to .myhospitalnow.com (notice the leading dot): 'domain' => env('SESSION_DOMAIN', '.myhospitalnow.com'),
3. Both microservices can now access the same session data, ensuring a unified login experience.

Pros:

• Simple to Implement: Works out of the box with Laravel’s built-in session handling.
• No Additional Tools Required: No need to set up external identity providers or manage tokens.
• Fast Performance: Shared Redis storage is highly efficient for session management.

Cons:

• Tightly Coupled Services: Services become dependent on shared infrastructure, reducing microservices’ independence.
• Scaling Limitation: If you later need to decouple these services or add new ones, this approach might not scale well.

Best Use Case:

• Recommended if both microservices will always share the same user base and run within the same domain/server environment.
• Suitable for small to medium-scale applications without plans to scale significantly in terms of microservices.

5. Synchronize Sessions Between Services

This approach involves synchronizing the session state between microservices whenever a user logs in or switches between them.

How It Works with Laravel:

1. When a user logs into one service (e.g., hospitals), notify the other service (doctors) by calling an API endpoint to synchronize the session.
2. The second service creates a local session using the shared authentication token or user data.

Example workflow:

• User logs into hospitals.
• The hospitals service generates a session token and sends it to the doctors service via an API request.
• The doctors service validates the token and creates a session for the user.

Pros:

• Loose Coupling: Services remain independent in terms of session storage.
• Security: Tokens can be short-lived and validated, reducing security risks.
• Flexibility: Easier to decouple or add more microservices later.

Cons:

• Implementation Complexity: Requires additional API endpoints and logic for session synchronization.
• Synchronization Delay: There’s a small risk of session state inconsistency if synchronization fails.

Best Use Case:

• Suitable if you want to maintain some level of independence between microservices but don’t want to implement full-fledged SSO.
• Works well if only a few services are involved.

Recommended Approach for Your Use Case

Given that your microservices are built using Laravel and hosted on the same server, and assuming there’s no immediate need to scale significantly, Option 2: Share the Session Across Microservices is the most practical and efficient solution.

Why Share the Session Across Microservices?

• Simple Implementation: Laravel natively supports session drivers like Redis or database, making it easy to configure shared sessions.
• Unified User Experience: Users stay logged in across both services without additional tools.
• Scalable for Current Needs: As long as both services share a user base and environment, this solution is sufficient.

Implementation Steps for Shared Sessions in Laravel

1. Configure Shared Session Storage:
   • Use Redis or another centralized session store.
   • Update .env for both services: SESSION_DRIVER=redis SESSION_CONNECTION=default SESSION_DOMAIN=.myhospitalnow.com
2. Set Cookie Domain for Cross-Service Access:
   • In config/session.php, set the domain to .myhospitalnow.com: 'domain' => env('SESSION_DOMAIN', '.myhospitalnow.com'),
3. Test Session Sharing:
   • Log into https://www.myhospitalnow.com/hospitals/.
   • Navigate to https://www.myhospitalnow.com/doctors/.
   • Verify that the user session persists across both services.
4. Secure the Session:
   • Use HTTPS to encrypt cookies and set the Secure and HttpOnly flags: 'secure' => env('SESSION_SECURE_COOKIE', true), 'http_only' => true,
5. Optional: Use Redis for High Performance:
   • Install and configure Redis: composer require predis/predis
   • Update .env for Redis connection: REDIS_HOST=127.0.0.1 REDIS_PASSWORD=null REDIS_PORT=6379

Future Consideration: Move to SSO

If you plan to add more microservices or scale the application significantly, transitioning to SSO (Option 1) would be a better long-term solution. You could use Laravel Passport or Laravel Sanctum to implement centralized authentication with minimal effort.

For now, sharing sessions provides an excellent balance of simplicity and functionality for your current setup.