deploy-pythonanywhere

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Translated

Deploy a Flask/WSGI app to PythonAnywhere free tier — automates webapp creation, code upload, WSGI config, reload, E2E test via MCP. Only CLI tool install needs user's Bash console.

4installs

Sourcehoangsoft90/ai_skills

Added on2026-08-20

NPX Install

npx skill4agent add hoangsoft90/ai_skills deploy-pythonanywhere

SKILL.md Content

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Deploy to PythonAnywhere

Automate Flask deployment to PA free tier via MCP tools. Only one step needs user's hands: install CLI tools in Bash console. Rest is agent-driven.

Pre-flight

Gather before starting:

App directory — local path containing app.py, templates/, etc.
App entry point — the Flask
```
app
```
import (e.g.
```
from app import app
```
).
External CLI tools — any binary the app shells out to (e.g.
```
officecli
```
). Agent cannot install these.
Python version — PA system Python (3.10+); no virtualenv needed — flask/openpyxl available in site-packages.

Gate: Items 1-3 confirmed. If app needs CLI tools, tell user to install them in PA Bash console BEFORE agent starts.

User steps (do these first, then hand off to agent)

User opens PA Bash console and runs what applies:

bash

# 1. pip install extras (if requirements.txt has packages beyond system site-packages)
pip install --user -r /home/<username>/<app-name>/requirements.txt

# 2. CLI tools (if app shells out to any)
curl -fsSL <install-url> | bash

No virtualenv needed — system Python has flask/openpyxl. Only run these if app needs extra packages or CLI tools.

Gate: User confirms

pip install

succeeded (if needed) + CLI tool

--version

works. Then agent takes over.

Agent steps (fully automated via MCP)

Step 1 — Upload code

python

upload_directory(
    local_dir_path="<local-app-dir>",
    remote_dir_path="/home/<username>/<app-name>"
)

Delete stale cache:

python

delete_path("/home/<username>/<app-name>/__pycache__")

Gate:

tree("/home/<username>/<app-name>")

shows all expected files; no

__pycache__

.

Step 2 — Create WSGI entry point

Upload WSGI file via

upload_text_file

:

python

upload_text_file(
    dest_path="/home/<username>/<app-name>/flask_app.py",
    content="""
import os, sys
os.environ["PATH"] = os.path.expanduser("~/.local/bin") + os.pathsep + os.environ.get("PATH", "")
sys.path.insert(0, os.path.expanduser("~/<app-name>"))
from app import app as application
"""
)

Key rules:

PATH line mandatory if app uses CLI in
```
~/.local/bin
```
```
sys.path.insert
```
before import
```
as application
```
is what uWSGI expects

Gate:

read_file_or_directory

confirms flask_app.py exists.

Step 3 — Create webapp

python

create_webapp(
    domain="<username>.pythonanywhere.com",
    python_version="3.12",
    virtualenv_path="",          # empty — use system Python
    project_path="/home/<username>/<app-name>"
)

If webapp already exists, skip to Step 4.

Gate:

get_webapp_info

returns webapp with correct

source_directory

.

Step 4 — Point WSGI to our file

python

patch_webapp(
    domain="<username>.pythonanywhere.com",
    data={"source_directory": "/home/<username>/<app-name>"}
)

Note: PA's WSGI file path is set at creation. If it doesn't match flask_app.py, user must set it in Web tab manually (no API for WSGI path).

Gate:

get_webapp_info

shows correct

source_directory

.

Step 5 — Reload

python

reload_webapp(domain="<username>.pythonanywhere.com")

Gate:

curl GET https://<user>.pythonanywhere.com/

returns 200.

Step 6 — E2E test

Homepage:
```
curl GET
```
→ 200.

Upload real file:

bash

curl -s -w "\nHTTP:%{http_code} TIME:%{time_total}" \
  --max-time 300 \
  -X POST -F "file=@<source-file>" \
  "https://<user>.pythonanywhere.com/<endpoint>" \
  -o /tmp/pa_result.xlsx

Verify output: correct row count, correct totals vs known-good reference.

Gate: HTTP 200, output validates. If 400/500, read error log:

python

read_file_or_directory("/var/log/<user>.pythonanywhere.com.error.log")

Diagnose + fix + reload + retest.

Gotchas (learned the hard way)

TemporaryDirectory
race. uWSGI lazy streaming +

TemporaryDirectory.__exit__

=

OSError: [Errno 39] Directory not empty

. Fix: manual

tempfile.mkdtemp()

+

shutil.rmtree(ignore_errors=True)

in

finally

,

send_file(io.BytesIO(result_bytes))

OUTSIDE try/finally.

Stale
__pycache__
. Python serves cached

.pyc

after source changes. Every deploy:

delete_path(__pycache__)

+

reload_webapp

. Symptom: old errors persist in error log.

send_file
needs file-like. Raw

bytes

→

AttributeError

. Wrap in

io.BytesIO()

.

Free tier sleep. 20-40s cold start after idle. Normal.

No virtualenv needed. PA system Python has flask/openpyxl in site-packages. Don't create one — wastes time.

WSGI path. PA sets this at webapp creation and shows it in Web tab. If it doesn't match the uploaded WSGI file, user must manually update in Web tab config (no API).

Deploy update (code change only)

When code changes but webapp already exists:

```
upload_directory
```
new code
```
delete_path(__pycache__)
```
```
reload_webapp
```
E2E test

Skip Steps 2-4 (webapp + WSGI already configured).

deploy-pythonanywhere

NPX Install

Tags

SKILL.md Content

Deploy to PythonAnywhere

Pre-flight

User steps (do these first, then hand off to agent)

Agent steps (fully automated via MCP)

Step 1 — Upload code

Step 2 — Create WSGI entry point

Step 3 — Create webapp

Step 4 — Point WSGI to our file

Step 5 — Reload

Step 6 — E2E test

Gotchas (learned the hard way)

Deploy update (code change only)