appmap-python is a Python package for recording
AppMaps of your code. “AppMap” is a data format
which records code structure (modules, classes, and methods), code execution events
(function calls and returns), and code metadata (repo name, repo URL, commit SHA, labels,
etc). It’s more granular than a performance profile, but it’s less granular than a full
debug trace. It’s designed to be optimal for understanding the design intent and structure
of code and key data flows.
There are several ways to record AppMaps of your Python program using the appmap package:
Run your tests (pytest, unittest) with the environment variable
APPMAP=true. An AppMap will be generated for each test case.
Use the appmap.record context manager to control recording. The context manager takes
an instance of an appmap.Recording, which can be used to generate the AppMap.
Run your application server with AppMap remote recording enabled, and use the AppMap browser extension to start, stop, and upload recordings.
Once you have made a recording, there are two ways to view automatically generated diagrams of the AppMaps.
The first option is to load the diagrams directly in your IDE, using the AppMap extension for PyCharm or VSCode.
The second option is to upload them to the AppMap Cloud using the AppMap CLI.
Support for new versions is added frequently, please check back regularly for updates.
If your project uses pip for dependency management, add the appmap package to the requirements
file or install it directly with
pip install appmap
For projects that use poetry , add the appmap package to pyproject.toml.
Add your modules as path entries in appmap.yml, and external packages
(distributions) as dist:
name: my_python_app
packages:
- path: app.mod1
shallow: true
- path: app.mod2
exclude:
- MyClass
- MyOtherClass.my_instance_method
- MyOtherClass.my_class_method
- dist: Django
exclude:
- django.db
Note that excludes are resolved relative to the associated path. So, for example, this
configuration excludes app.mod2.MyClass.
For external distribution packages
use the dist specifier; the names are looked up in the
database of installed Python distributions.
This is generally the same package name as you’d give to pip install or put
in pyproject.toml. You can additionally use path and exclude on dist
entries to limit the capture to specific patterns.
Note by default shallow capture is enabled on dist packages, supressing tracking
of most internal execution flow, which allows you to capture the interaction without
getting bogged down with detail. If this isn’t what you want, use shallow: false.
You can also use shallow: true on path entries.
APPMAP if true, code will be instrumented and AppMaps will be generated. Not
case-sensitive, defaults to ‘false’.
APPMAP_CONFIG specifies the configuration file to use. Defaults to appmap.yml in the
current directory
APPMAP_LOG_LEVEL specifies log level to use, from the set CRITICAL, ERROR,
WARNING, INFO, DEBUG. Not case-sensitive, defaults to WARNING.
APPMAP_OUTPUT_DIR specifies the root directory for writing AppMaps. Defaults to
tmp/appmap.
APPMAP_DISPLAY_PARAMS enables rendering of parameters as strings. If true (the
default, not case-sensitive), parameters are rendered using repr. If
false, a generic string is used instead.
The AppMap data format provides for class and
function labels, which can be used to enhance the AppMap visualizations, and to
programatically analyze the data.
You can apply function labels using the appmap.labels decorator in your Python code. To
apply a labels to a function, decorate the function with @appmap.labels.
For example
import appmap.labels
class ApiKey
@appmap.labels('provider.authentication', 'security')
def authenticate(self, key):
# logic to verify the key here...
Then the AppMap metadata section for this function will include:
{
"name": "authenticate",
"type": "function",
"labels": [ "provider.authentication", "security" ]
}
appmap-python supports recording pytest and
unittest test cases.
appmap-python is a pytest plugin. When it’s installed in a project that uses
pytest, it will be available to generate AppMaps.
[email protected]:/src/appmap/test/data/pytest# pip show appmap
Name: appmap
Version: 0.0.0
Summary: Create AppMap files by recording a Python application.
Home-page: None
Author: Alan Potter
Author-email: [email protected]
License: None
Location: /usr/local/lib/python3.9/site-packages
Requires: orjson, PyYAML, inflection
Required-by:
[email protected]:/src/appmap/test/data/pytest# APPMAP=true APPMAP_LOG_LEVEL=info pytest -svv
[2021-02-10 11:37:59,345] INFO root: appmap enabled: True
[2021-02-10 11:37:59,350] INFO appmap._implementation.configuration: ConfigFilter, includes {'simple'}
[2021-02-10 11:37:59,350] INFO appmap._implementation.configuration: ConfigFilter, excludes set()
===================================================================== test session starts =====================================================================
platform linux -- Python 3.9.1, pytest-6.2.2, py-1.10.0, pluggy-0.13.1 -- /usr/local/bin/python
cachedir: .pytest_cache
rootdir: /src, configfile: pytest.ini
plugins: appmap-0.0.0
collected 1 item
test_simple.py::test_hello_world [2021-02-10 11:37:59,482] INFO appmap.pytest: starting recording /tmp/pytest/test_hello_world.appmap.json
[2021-02-10 11:37:59,484] INFO appmap._implementation.configuration: included class simple.Simple
[2021-02-10 11:37:59,484] INFO appmap._implementation.configuration: included function simple.Simple.hello
[2021-02-10 11:37:59,489] INFO appmap._implementation.configuration: included function simple.Simple.hello_world
[2021-02-10 11:37:59,490] INFO appmap._implementation.configuration: included function simple.Simple.world
[2021-02-10 11:37:59,828] INFO appmap.pytest: wrote recording /tmp/pytest/test_hello_world.appmap.json
PASSED
====================================================================== 1 passed in 0.45s ======================================================================
import appmap.unittest. Instruments subclasses of unittest.TestCase and records each
test_* function in the subclasses. You can also use python -m appmap.unittest exactly like
python -m unittest and leave your code unmodified (just remember to set the APPMAP=true
environment variable).
Once you’ve configured your tests to generate AppMaps, run the tests with the
APPMAP=true in the environment. For example, to run a pytest test suite:
$ APPMAP=true pytest
appmap-python supports remote recording of Django and Flask web applications. Import the
appropriate remote recording support into your web app.
Add appmap.django.Middleware to your MIDDLEWARE.
For projects that use a Flask application
factory, installing
appmap-python automatically configures the project for remote recording. No further
modifications are required. When the application initializes, appmap-python adds
middleware that handles the /_appmap/record routes.
For projects that don’t provide an application factory, appmap-python can be used as a
Flask extension.
For example:
from flask import Flask
from appmap.flask import AppmapFlask
app = Flask(__name__)
appmap_flask = AppmapFlask(app)
This will add the /_appmap/record routes your app.
Once you’ve configured your web app to add the remote-recording routes, you can use the routes to manage recordings. The AppMap browser extension, CLI, or just plain cURL will all work for this.
As when running tests, start the web server with APPMAP=true in the environment. For
example, to start a Flask app:
$ APPMAP=true flask run
An app with remote recording enabled supports these routes:
POST /_appmap/record
Starts a new recording
200 if the recording was started successfully 409 if there’s already a recording in progress
GET /_appmap/record
Returns JSON describing current recording state
200 with body
{
"enabled": true
}
enabled indicates whether recording has been enabled
DELETE /_appmap/record
Returns AppMap as JSON
200 with AppMap as body
404 if there’s no recording in progress
You can use appmap.record as a context manager to record your code.
With a file called record_sample.py like this
import os
import sys
import appmap
r = appmap.Recording()
with r:
import sample
print(sample.C().hello_world(), file=sys.stderr)
with os.fdopen(sys.stdout.fileno(), "wb", closefd=False) as stdout:
stdout.write(appmap.generation.dump(r))
stdout.flush()
and a source file called sample.py like this
class C:
def make_str(self, s):
return s;
def hello_world(self):
return f'{self.make_str("Hello")} {self.make_str("world!")}'
as well as an appmap.yml
name: sample
packages:
- path: sample
you can generate a recording of the code
% APPMAP=true python record_sample.py > record_sample.appmap.json
% jq '.events | length' record_sample.appmap.json
6
% jq < record_sample.appmap.json | head -10
{
"version": "1.4",
"metadata": {
"language": {
"name": "python",
"engine": "CPython",
"version": "3.9.1"
},
"client": {
"name": "appmap",
https://github.com/applandinc/appmap-python
https://app.land can be used to store, analyze, and share AppMaps.
For instructions on uploading, see the documentation of the AppMap Cloud CLI.