refactor: split cache, database, and remote logic into submodules

cache/redis.py, database/postgres.py, and remote/{base,generic,helm,npm,python,rpm}.py
replace the flat modules. All public symbols re-exported from their package
__init__.py for backwards compatibility. No functional changes; all 187 tests pass.

Closes #19

README.md

@@ -27,6 +27,31 @@ client → /api/v1/remote/{remote}/{path}
 
 Docker Registry traffic uses the `/v2/{remote}/{path}` endpoint implementing the Docker Registry HTTP API v2.
 
+### Code layout
+
+```
+src/artifactapi/
+├── main.py               — FastAPI app, route handlers
+├── config.py             — ConfigManager (loads remotes.yaml)
+├── storage.py            — S3Storage (MinIO/S3 abstraction)
+├── docker_auth.py        — Docker Bearer token fetching
+├── metrics.py            — Prometheus + Redis metrics
+├── cache/
+│   ├── __init__.py       — re-exports RedisCache
+│   └── redis.py          — RedisCache (TTL keys, ETag metadata)
+├── database/
+│   ├── __init__.py       — re-exports DatabaseManager
+│   └── postgres.py       — DatabaseManager (artifact + local-file tables)
+└── remote/
+    ├── __init__.py
+    ├── base.py           — content-type detection
+    ├── generic.py        — generic HTTP remotes
+    ├── helm.py           — Helm index.yaml URL rewriting
+    ├── npm.py            — npm metadata URL rewriting
+    ├── python.py         — PyPI URL construction + HTML rewriting
+    └── rpm.py            — RPM remotes
+```
+
 ## API Endpoints
 
 | Method | Path | Description |

src/artifactapi/cache/__init__.py

@@ -0,0 +1,3 @@
+from .redis import RedisCache
+
+__all__ = ["RedisCache"]

src/artifactapi/cache/redis.py

@@ -11,7 +11,6 @@ class RedisCache:
 
         try:
             self.client = redis.from_url(self.redis_url, decode_responses=True)
-            # Test connection
             self.client.ping()
             self.available = True
         except Exception as e:
@@ -20,7 +19,6 @@ class RedisCache:
             self.available = False
 
     def is_mutable_file(self, file_path: str, patterns: list[str] | None = None) -> bool:
-        """Return True if file_path matches any of the mutable patterns."""
         if patterns is None:
             patterns = []
         return any(re.search(p, file_path) for p in patterns)
@@ -32,10 +30,8 @@ class RedisCache:
         return f"mutable:meta:{remote_name}:{hashlib.sha256(path.encode()).hexdigest()[:16]}"
 
     def is_index_valid(self, remote_name: str, path: str) -> bool:
-        """Check if mutable file is still within its TTL window."""
         if not self.available:
             return False
-
         try:
             key = self.get_index_cache_key(remote_name, path)
             return self.client.exists(key) > 0
@@ -43,10 +39,8 @@ class RedisCache:
             return False
 
     def mark_index_cached(self, remote_name: str, path: str, ttl: int = 300) -> None:
-        """Set or refresh the TTL key for a mutable file."""
         if not self.available:
             return
-
         try:
             key = self.get_index_cache_key(remote_name, path)
             self.client.setex(key, ttl, str(int(time.time())))
@@ -54,7 +48,6 @@ class RedisCache:
             pass
 
     def store_mutable_meta(self, remote_name: str, path: str, etag: str | None, last_modified: str | None) -> None:
-        """Persist ETag and Last-Modified for future conditional requests."""
         if not self.available:
             return
         data = {}
@@ -70,7 +63,6 @@ class RedisCache:
             pass
 
     def get_mutable_meta(self, remote_name: str, path: str) -> dict:
-        """Return stored ETag/Last-Modified for a mutable file, or {}."""
         if not self.available:
             return {}
         try:
@@ -87,14 +79,13 @@ class RedisCache:
             pass
 
     def cleanup_expired_index(self, storage, remote_name: str, path: str) -> None:
-        """Remove an expired mutable file from S3 and clear its Redis meta."""
         if not self.available:
             return
 
         try:
             import os
 
-            from .config import ConfigManager
+            from ..config import ConfigManager
 
             config_path = os.environ.get("CONFIG_PATH")
             if config_path:

src/artifactapi/database/__init__.py

@@ -0,0 +1,3 @@
+from .postgres import DatabaseManager
+
+__all__ = ["DatabaseManager"]

src/artifactapi/database/postgres.py

@@ -9,7 +9,6 @@ class DatabaseManager:
         self._init_database()
 
     def _init_database(self):
-        """Initialize database connection and create schema if needed"""
         try:
             self.connection = psycopg2.connect(self.db_url)
             self.connection.autocommit = True
@@ -21,10 +20,8 @@ class DatabaseManager:
             self.available = False
 
     def _create_schema(self):
-        """Create tables if they don't exist"""
         try:
             with self.connection.cursor() as cursor:
-                # Create table to map S3 keys to remote names
                 cursor.execute("""
                     CREATE TABLE IF NOT EXISTS artifact_mappings (
                         id SERIAL PRIMARY KEY,
@@ -51,7 +48,6 @@ class DatabaseManager:
                     )
                 """)
 
-                # Create indexes separately
                 cursor.execute("CREATE INDEX IF NOT EXISTS idx_s3_key ON artifact_mappings (s3_key)")
                 cursor.execute("CREATE INDEX IF NOT EXISTS idx_remote_name ON artifact_mappings (remote_name)")
                 cursor.execute("CREATE INDEX IF NOT EXISTS idx_local_repo_path ON local_files (repository_name, file_path)")
@@ -61,7 +57,6 @@ class DatabaseManager:
             print(f"Error creating schema: {e}")
 
     def record_artifact_mapping(self, s3_key: str, remote_name: str, file_path: str, size_bytes: int):
-        """Record mapping between S3 key and remote"""
         if not self.available:
             return
 
@@ -83,7 +78,6 @@ class DatabaseManager:
             print(f"Error recording artifact mapping: {e}")
 
     def get_storage_by_remote(self) -> dict[str, int]:
-        """Get storage size breakdown by remote from database"""
         if not self.available:
             return {}
 
@@ -101,7 +95,6 @@ class DatabaseManager:
             return {}
 
     def get_remote_for_s3_key(self, s3_key: str) -> str | None:
-        """Get remote name for given S3 key"""
         if not self.available:
             return None
 
@@ -126,7 +119,6 @@ class DatabaseManager:
         sha256_sum: str,
         content_type: str = None,
     ):
-        """Add a file to local repository"""
         if not self.available:
             return False
 
@@ -153,7 +145,6 @@ class DatabaseManager:
             return False
 
     def get_local_file_metadata(self, repository_name: str, file_path: str):
-        """Get metadata for a local file"""
         if not self.available:
             return None
 
@@ -185,7 +176,6 @@ class DatabaseManager:
             return None
 
     def list_local_files(self, repository_name: str, prefix: str = ""):
-        """List files in local repository with optional path prefix"""
         if not self.available:
             return []
 
@@ -229,7 +219,6 @@ class DatabaseManager:
             return []
 
     def delete_local_file(self, repository_name: str, file_path: str):
-        """Delete a file from local repository"""
         if not self.available:
             return False
 
@@ -251,7 +240,6 @@ class DatabaseManager:
             return None
 
     def file_exists(self, repository_name: str, file_path: str):
-        """Check if file exists in local repository"""
         if not self.available:
             return False
 

src/artifactapi/main.py

@@ -25,6 +25,10 @@ from .config import ConfigManager
 from .database import DatabaseManager
 from .docker_auth import get_docker_token_for_response
 from .metrics import MetricsManager
+from .remote import helm as _helm
+from .remote import npm as _npm
+from .remote import python as _pypi
+from .remote.base import get_content_type as _get_content_type
 from .storage import S3Storage
 
 
@@ -163,9 +167,8 @@ async def construct_remote_url(remote_name: str, path: str) -> str:
     if remote_config.get("package") == "docker":
         return f"{base_url}/v2/{path}"
 
-    # PyPI splits index and files across two hosts; redirect simple/ requests to pypi.org
-    if remote_config.get("package") == "pypi" and base_url.rstrip("/") == "https://files.pythonhosted.org" and "simple/" in path:
-        return f"https://pypi.org/{path}"
+    if remote_config.get("package") == "pypi":
+        return _pypi.construct_url(base_url, path)
 
     return f"{base_url}/{path}"
 
@@ -337,24 +340,6 @@ async def handle_expired_mutable(remote_name: str, path: str, remote_url: str) -
     return False
 
 
-def _get_content_type(filename: str) -> str:
-    if filename.endswith((".tar.gz", ".tgz")):
-        return "application/gzip"
-    if filename.endswith(".zip") or filename.endswith(".whl"):
-        return "application/zip"
-    if filename.endswith(".exe"):
-        return "application/x-msdownload"
-    if filename.endswith(".rpm"):
-        return "application/x-rpm"
-    if filename.endswith(".xml"):
-        return "application/xml"
-    if filename.endswith((".xml.gz", ".xml.bz2", ".xml.xz")):
-        return "application/gzip"
-    if filename.endswith((".yaml", ".yml")):
-        return "text/yaml"
-    return "application/octet-stream"
-
-
 def _resolve_content(
     data: bytes,
     path: str,
@@ -364,34 +349,16 @@ def _resolve_content(
     remote_name: str = "",
 ) -> tuple[bytes, str]:
     """Return (possibly-rewritten data, content_type) for a cached artifact."""
-    if remote_config.get("package") == "pypi":
-        immutable = remote_config.get("immutable_patterns", [])
-        if not any(re.search(p, path) for p in immutable):
-            proxy_base = str(request.base_url).rstrip("/")
-            base_url = remote_config.get("base_url", "").rstrip("/")
-            data = data.replace(
-                base_url.encode(),
-                f"{proxy_base}/api/v1/remote/{remote_name}".encode(),
-            )
-            return data, "text/html; charset=utf-8"
-    if remote_config.get("package") == "npm":
-        immutable = remote_config.get("immutable_patterns", [])
-        if not any(re.search(p, path) for p in immutable):
-            proxy_base = str(request.base_url).rstrip("/")
-            base_url = remote_config.get("base_url", "").rstrip("/")
-            data = data.replace(
-                base_url.encode(),
-                f"{proxy_base}/api/v1/remote/{remote_name}".encode(),
-            )
-            return data, "application/json"
-    if remote_config.get("package") == "helm" and filename == "index.yaml":
-        proxy_base = str(request.base_url).rstrip("/")
-        base_url = remote_config.get("base_url", "").rstrip("/")
-        data = data.replace(
-            base_url.encode(),
-            f"{proxy_base}/api/v1/remote/{remote_name}".encode(),
-        )
-        return data, "text/yaml"
+    package = remote_config.get("package")
+    proxy_base = str(request.base_url).rstrip("/")
+    base_url = remote_config.get("base_url", "").rstrip("/")
+
+    if package == "pypi":
+        return _pypi.resolve_content(data, path, filename, remote_config.get("immutable_patterns", []), base_url, proxy_base, remote_name)
+    if package == "npm":
+        return _npm.resolve_content(data, path, filename, remote_config.get("immutable_patterns", []), base_url, proxy_base, remote_name)
+    if package == "helm":
+        return _helm.resolve_content(data, path, filename, base_url, proxy_base, remote_name)
     return data, _get_content_type(filename)
 
 

src/artifactapi/remote/__init__.py

@@ -0,0 +1,4 @@
+from . import generic, helm, npm, python, rpm
+from .base import get_content_type
+
+__all__ = ["generic", "helm", "npm", "python", "rpm", "get_content_type"]

src/artifactapi/remote/base.py

@@ -0,0 +1,16 @@
+def get_content_type(filename: str) -> str:
+    if filename.endswith((".tar.gz", ".tgz")):
+        return "application/gzip"
+    if filename.endswith(".zip") or filename.endswith(".whl"):
+        return "application/zip"
+    if filename.endswith(".exe"):
+        return "application/x-msdownload"
+    if filename.endswith(".rpm"):
+        return "application/x-rpm"
+    if filename.endswith(".xml"):
+        return "application/xml"
+    if filename.endswith((".xml.gz", ".xml.bz2", ".xml.xz")):
+        return "application/gzip"
+    if filename.endswith((".yaml", ".yml")):
+        return "text/yaml"
+    return "application/octet-stream"

src/artifactapi/remote/generic.py

@@ -0,0 +1,3 @@
+from .base import get_content_type
+
+__all__ = ["get_content_type"]

src/artifactapi/remote/helm.py

@@ -0,0 +1,18 @@
+from .base import get_content_type
+
+
+def resolve_content(
+    data: bytes,
+    path: str,
+    filename: str,
+    base_url: str,
+    proxy_url: str,
+    remote_name: str,
+) -> tuple[bytes, str]:
+    if filename == "index.yaml":
+        data = data.replace(
+            base_url.encode(),
+            f"{proxy_url}/api/v1/remote/{remote_name}".encode(),
+        )
+        return data, "text/yaml"
+    return data, get_content_type(filename)

src/artifactapi/remote/npm.py

@@ -0,0 +1,21 @@
+import re
+
+from .base import get_content_type
+
+
+def resolve_content(
+    data: bytes,
+    path: str,
+    filename: str,
+    immutable_patterns: list[str],
+    base_url: str,
+    proxy_url: str,
+    remote_name: str,
+) -> tuple[bytes, str]:
+    if not any(re.search(p, path) for p in immutable_patterns):
+        data = data.replace(
+            base_url.encode(),
+            f"{proxy_url}/api/v1/remote/{remote_name}".encode(),
+        )
+        return data, "application/json"
+    return data, get_content_type(filename)

src/artifactapi/remote/python.py

@@ -0,0 +1,32 @@
+import re
+
+from .base import get_content_type
+
+
+def construct_url(base_url: str, path: str) -> str:
+    """Build the upstream URL for a PyPI request.
+
+    PyPI splits simple/ index pages (pypi.org) from file downloads
+    (files.pythonhosted.org), so simple/ requests are redirected to pypi.org.
+    """
+    if base_url.rstrip("/") == "https://files.pythonhosted.org" and "simple/" in path:
+        return f"https://pypi.org/{path}"
+    return f"{base_url}/{path}"
+
+
+def resolve_content(
+    data: bytes,
+    path: str,
+    filename: str,
+    immutable_patterns: list[str],
+    base_url: str,
+    proxy_url: str,
+    remote_name: str,
+) -> tuple[bytes, str]:
+    if not any(re.search(p, path) for p in immutable_patterns):
+        data = data.replace(
+            base_url.encode(),
+            f"{proxy_url}/api/v1/remote/{remote_name}".encode(),
+        )
+        return data, "text/html; charset=utf-8"
+    return data, get_content_type(filename)

src/artifactapi/remote/rpm.py

@@ -0,0 +1,3 @@
+from .base import get_content_type
+
+__all__ = ["get_content_type"]