refactor: Add JobSummary and Transaction models, client to get currency exchange rate

app/clients/exchange_rate_client.py

@@ -0,0 +1,70 @@
+import httpx
+import redis
+from app.core.config import settings
+from app.core.logging import logger
+
+
+class ExchangeRateClient:
+    def __init__(self):
+        self.default_rate = 93.0
+        self.cache_key = "usd_to_inr_rate"
+        self.cache_ttl = 86400  # 24 hours cache duration
+        try:
+            self.redis_client = redis.Redis(
+                host=settings.REDIS_HOST,
+                port=settings.REDIS_PORT,
+                db=settings.REDIS_DB,
+                decode_responses=True,
+            )
+        except Exception as e:
+            logger.warning(f"Could not connect to Redis for exchange rate caching: {e}")
+            self.redis_client = None
+
+    async def get_usd_to_inr_rate(self) -> float:
+        """
+        Retrieves the USD to INR conversion rate.
+        Checks Redis cache first. If cache is empty/offline, fetches from a free public API
+        and updates the cache. Falls back to a hardcoded default rate if both fail.
+        """
+        # read from cache
+        if self.redis_client:
+            try:
+                cached_rate = self.redis_client.get(self.cache_key)
+                if cached_rate:
+                    logger.info("Retrieved exchange rate from Redis cache.")
+                    return float(cached_rate)
+            except Exception as e:
+                logger.warning(f"Failed to read exchange rate from Redis: {e}")
+
+        # fetching from Exchange Rate API
+        try:
+            logger.info("Fetching live exchange rate from API...")
+            async with httpx.AsyncClient(timeout=5.0) as client:
+                response = await client.get("https://open.er-api.com/v6/latest/USD")
+                if response.status_code == 200:
+                    data = response.json()
+                    rates = data.get("rates", {})
+                    inr_rate = rates.get("INR")
+                    if inr_rate:
+                        inr_rate = float(inr_rate)
+                        logger.info(
+                            f"Successfully fetched live exchange rate: {inr_rate}"
+                        )
+                        # Cache the rate in Redis
+                        if self.redis_client:
+                            try:
+                                self.redis_client.set(
+                                    self.cache_key, str(inr_rate), ex=self.cache_ttl
+                                )
+                            except Exception as ce:
+                                logger.warning(
+                                    f"Failed to cache exchange rate in Redis: {ce}"
+                                )
+                        return inr_rate
+        except Exception as e:
+            logger.error(
+                f"Error fetching live exchange rate: {e}. Falling back to default rate {self.default_rate}"
+            )
+
+        # 3. Fallback
+        return self.default_rate