Module started_get 

Implementation of the GET /health/started endpoint

This module provides an HTTP endpoint to monitor the start of the Cat Gateway service, which depends on multiple parameters. It uses atomic booleans to track the status of the service and its dependencies.

Key Features

1. Atomic Booleans for Initialization:

   • STARTED: Indicates whether the service has fully initialized. It defaults to false on startup and can only transition to true once all required conditions are met. Once set to true, it cannot be changed back to false.
   • LIVE_INDEX_DB and LIVE_EVENT_DB: Track the connection status of the Index DB and Event DB, respectively. Both default to false on startup and are set to true once a successful connection is established.
   • A third atomic boolean (e.g., INITIAL_FOLLOWER_TIP_REACHED) is used to track whether the chain indexer has reached the tip of the chain for the first time. This also defaults to false and is set to true once the condition is met.

2. Initialization Logic:

   • On startup, the service attempts to connect to both databases (Index DB and Event DB). It will keep retrying until both connections are successful. Once both databases are connected, their respective flags (LIVE_INDEX_DB and LIVE_EVENT_DB) are set to true.
   • The STARTED flag is set to true only when all three conditions are met simultaneously:
     1. LIVE_INDEX_DB is true.
     2. LIVE_EVENT_DB is true.
     3. INITIAL_FOLLOWER_TIP_REACHED is true.
   • Once STARTED is set to true, it cannot be changed back to false.

3. Response Logic:

   • If STARTED is true, the endpoint returns a 204 No Content response, indicating that the service is fully initialized and operational.
   • If STARTED is false, the endpoint returns a 503 Service Unavailable response, indicating that the service is not yet ready to handle requests.

How It Works

• On startup, the service attempts to connect to the Index DB and Event DB. It retries until both connections are successful. Once connected, their respective flags (LIVE_INDEX_DB and LIVE_EVENT_DB) are set to true.
• The chain indexer monitors the blockchain and sets INITIAL_FOLLOWER_TIP_REACHED to true once it reaches the tip of the chain for the first time.
• When all three flags (LIVE_INDEX_DB, LIVE_EVENT_DB, and INITIAL_FOLLOWER_TIP_REACHED) are true, the STARTED flag is set to true.
• Once STARTED is true, the endpoint will always respond with 204 No Content.
• If STARTED is false, the endpoint will respond with 503 Service Unavailable.

Example Scenarios

1. Startup Phase:

   • The service is starting up.
   • LIVE_INDEX_DB, LIVE_EVENT_DB, and INITIAL_FOLLOWER_TIP_REACHED are all false.
   • STARTED is false.
   • The endpoint returns 503 Service Unavailable.

2. Databases Connected, Indexer Not Ready:

   • The Index DB and Event DB are connected (LIVE_INDEX_DB and LIVE_EVENT_DB are true).
   • The chain indexer has not yet reached the tip of the chain (INITIAL_FOLLOWER_TIP_REACHED is false).
   • STARTED is false.
   • The endpoint returns 503 Service Unavailable.

3. All Conditions Met:

   • The Index DB and Event DB are connected (LIVE_INDEX_DB and LIVE_EVENT_DB are true).
   • The chain indexer has reached the tip of the chain (INITIAL_FOLLOWER_TIP_REACHED is true).
   • STARTED is set to true.
   • The endpoint returns 204 No Content.

4. After Initialization:

   • All flags (LIVE_INDEX_DB, LIVE_EVENT_DB, INITIAL_FOLLOWER_TIP_REACHED, and STARTED) are true.
   • The endpoint continues to return 204 No Content.

Notes

• All booleans are atomic, meaning they are thread-safe and can be accessed concurrently without issues.
• Once STARTED is set to true, it cannot be reverted, ensuring that the service remains in a consistent state after initialization.

This endpoint is useful for monitoring the initialization status of a service that depends on multiple external systems, ensuring that the service only becomes available once all dependencies are ready.

Enums

Responses 🔒

Endpoint responses.

Functions

endpoint 🔒

GET /health/started

Type Aliases

AllResponses 🔒

All responses.