cli: ensure the connection always get closed in github.py (#31914)

Thank you for contributing to LangChain!

- [x] **PR title**: "package: description"
- Where "package" is whichever of langchain, core, etc. is being
modified. Use "docs: ..." for purely docs changes, "infra: ..." for CI
changes.
  - Example: "core: add foobar LLM"


- [x] **PR message**: ***Delete this entire checklist*** and replace
with
    - **Description:** a description of the change
    - **Issue:** the issue # it fixes, if applicable
    - **Dependencies:** any dependencies required for this change
- **Twitter handle:** if your PR gets announced, and you'd like a
mention, we'll gladly shout you out!


- [x] **Add tests and docs**: If you're adding a new integration, please
include
1. a test for the integration, preferably unit tests that do not rely on
network access,
2. an example notebook showing its use. It lives in
`docs/docs/integrations` directory.


- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/

Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to pyproject.toml files (even optional
ones) unless they are required for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.

If no one reviews your PR within a few days, please @-mention one of
baskaryan, eyurtsev, ccurme, vbarda, hwchase17.

Author: MichaelLi65535

libs/cli/langchain_cli/utils/github.py

@@ -3,26 +3,30 @@
 from typing import Optional
 
 
-def list_packages(*, contains: Optional[str] = None):
+def list_packages(*, contains: Optional[str] = None) -> list[str]:
     conn = http.client.HTTPSConnection("api.github.com")
+    try:
+        headers = {
+            "Accept": "application/vnd.github+json",
+            "X-GitHub-Api-Version": "2022-11-28",
+            "User-Agent": "langchain-cli",
+        }
 
-    headers = {
-        "Accept": "application/vnd.github+json",
-        "X-GitHub-Api-Version": "2022-11-28",
-        "User-Agent": "langchain-cli",
-    }
+        conn.request(
+            "GET",
+            "/repos/langchain-ai/langchain/contents/templates",
+            headers=headers,
+        )
+        res = conn.getresponse()
 
-    conn.request(
-        "GET",
-        "/repos/langchain-ai/langchain/contents/templates",
-        headers=headers,
-    )
-    res = conn.getresponse()
+        res_str = res.read()
 
-    res_str = res.read()
-
-    data = json.loads(res_str)
-    package_names = [
-        p["name"] for p in data if p["type"] == "dir" and p["name"] != "docs"
-    ]
-    return [p for p in package_names if contains in p] if contains else package_names
+        data = json.loads(res_str)
+        package_names = [
+            p["name"] for p in data if p["type"] == "dir" and p["name"] != "docs"
+        ]
+        return (
+            [p for p in package_names if contains in p] if contains else package_names
+        )
+    finally:
+        conn.close()