refactor: optimize API keys reading (#6655)

* centralize API keys handling

* fix mypy and pylint

* rm utility function, be more explicit

haystack/components/converters/azure.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 from typing import List, Union, Dict, Any, Optional
-import os
 import logging
+import os
 
 from haystack.lazy_imports import LazyImport
 from haystack import component, Document, default_to_dict
@@ -51,16 +51,15 @@ class AzureOCRDocumentConverter:
         """
         azure_import.check()
 
-        if api_key is None:
-            try:
-                api_key = os.environ["AZURE_AI_API_KEY"]
-            except KeyError as e:
-                raise ValueError(
-                    "AzureOCRDocumentConverter expects an Azure Credential key. "
-                    "Set the AZURE_AI_API_KEY environment variable (recommended) or pass it explicitly."
-                ) from e
+        api_key = api_key or os.environ.get("AZURE_AI_API_KEY")
+        # we check whether api_key is None or an empty string
+        if not api_key:
+            msg = (
+                "AzureOCRDocumentConverter expects an API key. "
+                "Set the AZURE_AI_API_KEY environment variable (recommended) or pass it explicitly."
+            )
+            raise ValueError(msg)
 
-        self.api_key = api_key
         self.document_analysis_client = DocumentAnalysisClient(
             endpoint=endpoint, credential=AzureKeyCredential(api_key)
         )

haystack/components/websearch/searchapi.py

@@ -1,7 +1,7 @@
 import json
-import os
 import logging
 from typing import Dict, List, Optional, Any
+import os
 
 import requests
 
@@ -42,14 +42,15 @@ class SearchApiWebSearch:
         For example, you can set 'num' to 100 to increase the number of search results.
         See the [SearchApi website](https://www.searchapi.io/) for more details.
         """
-        if api_key is None:
-            try:
-                api_key = os.environ["SEARCHAPI_API_KEY"]
-            except KeyError as e:
-                raise ValueError(
-                    "SearchApiWebSearch expects an API key. "
-                    "Set the SEARCHAPI_API_KEY environment variable (recommended) or pass it explicitly."
-                ) from e
+        api_key = api_key or os.environ.get("SEARCHAPI_API_KEY")
+        # we check whether api_key is None or an empty string
+        if not api_key:
+            msg = (
+                "SearchApiWebSearch expects an API key. "
+                "Set the SEARCHAPI_API_KEY environment variable (recommended) or pass it explicitly."
+            )
+            raise ValueError(msg)
+
         self.api_key = api_key
         self.top_k = top_k
         self.allowed_domains = allowed_domains

haystack/components/websearch/serper_dev.py

@@ -1,7 +1,7 @@
 import json
-import os
 import logging
 from typing import Dict, List, Optional, Any
+import os
 
 import requests
 
@@ -42,15 +42,15 @@ class SerperDevWebSearch:
         For example, you can set 'num' to 20 to increase the number of search results.
         See the [Serper Dev website](https://serper.dev/) for more details.
         """
-        if api_key is None:
-            try:
-                api_key = os.environ["SERPERDEV_API_KEY"]
-            except KeyError as e:
-                raise ValueError(
-                    "SerperDevWebSearch expects an API key. "
-                    "Set the SERPERDEV_API_KEY environment variable (recommended) or pass it explicitly."
-                ) from e
-            raise ValueError("API key for SerperDev API must be set.")
+        api_key = api_key or os.environ.get("SERPERDEV_API_KEY")
+        # we check whether api_key is None or an empty string
+        if not api_key:
+            msg = (
+                "SerperDevWebSearch expects an API key. "
+                "Set the SERPERDEV_API_KEY environment variable (recommended) or pass it explicitly."
+            )
+            raise ValueError(msg)
+
         self.api_key = api_key
         self.top_k = top_k
         self.allowed_domains = allowed_domains

test/components/converters/test_azure_ocr_doc_converter.py

@@ -10,7 +10,7 @@ from haystack.dataclasses import ByteStream
 class TestAzureOCRDocumentConverter:
     def test_init_fail_wo_api_key(self, monkeypatch):
         monkeypatch.delenv("AZURE_AI_API_KEY", raising=False)
-        with pytest.raises(ValueError, match="AzureOCRDocumentConverter expects an Azure Credential key"):
+        with pytest.raises(ValueError):
             AzureOCRDocumentConverter(endpoint="test_endpoint")
 
     def test_to_dict(self):