pytest-fluent 0.4.1
A pytest plugin in order to provide logs via fluentd
License: MIT
Requires Python: >=3.8
Keywords: pytest, logging, fluent

# pytest-fluent

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_pytest-fluent_ is a Python package in order to extend _pytest_ using _Fluentd_ for logging test results.

## Description

_pytest_ is one of the most powerful testing suites with a lot of functionality and many plugins. _Fluentd_ is a well-established log collector which is used in many modern web architectures. So, why not putting both worlds together in order to gain real-time log access to your distributed test runs?

_pytest-fluent_ enables you to forward your test data immediately to your preferred log-sink from any node spread around your infrastructure. The streamed data are available for each pytest stage and formatted in JSON.

Each _pytest_ session gets an unique identifier (UID) assigned as well as each executed test case. With these UIDs, you can easily filter sessions and testcase data entries, for instance in your favorite database.

## Installation

The package is available at [pypi.org](https://pypi.org/project/pytest-fluent/) and can be installed by typing

```shell
pip install pytest-fluent
```

## Usage

_pytest-fluent-logging_ forwards meta data from _pytest_ to _Fluentd_ for further processing. The meta data are

* unique session ID
* unique test ID
* status of the session respectively test case
* test case name
* test results
* `record_property` entries
* custom testcase information
* custom session information
* timestamps

Furthermore, the Python logging instance can be extended in order to forward test case runtime logging:

```python
from logging import getLogger

def test_my_runtime_log():
    value = 1
    getLogger().info("Setting value to %s", value)
    assert value == 1
```

or:

```python
from logging import getLogger

def test_my_runtime_log():
    value = 1
    getLogger('fluent').info("Setting value to %s", value)
    assert value == 1
```

### Fixtures

In order to create your own logger, request the fixture `get_logger` as follows:

```python
def test_my_runtime_log(get_logger):
    logger = get_logger('my.Logger')
    value = 1
    logger.info("Setting value to %s", value)
    assert value == 1
```

If you want to get the current UIDs, use the `session_uid` and `test_uid` fixtures as follows:

```python
def test_unique_identifier(get_logger, session_uid, test_uid):
    logger = get_logger('fluent')
    logger.info("Session ID: %s", session_uid)
    logger.info("Test ID: %s", test_uid)
    value = 1
    assert value == 1
```

### Callbacks

If you want to add custom data to the datasets of the `pytest_sessionstart` and `pytest_runtest_logstart` stages, decorate your callback functions with the following decorators:

```python
from pytest_fluent import (
    additional_session_information_callback,
    additional_test_information_callback
)

@additional_session_information_callback
def provide_more_session_information() -> dict:
    return {
        "more": "session information"
    }

@additional_test_information_callback
def provide_more_test_information() -> dict:
    return {
        "more": "test information"
    }
```

### _pytest_ CLI extensions

The _pytest_ CLI application can be called with the following arguments in order to configure _fluent-logging_.

| argument            | description                                                                                                                          | default  |
| ------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | -------- |
| --session-uuid      | Use a custom externally created UUID, e.g. link a CI job with the pytest session.                                                    |          |
| --fluentd-host      | Fluentd host address. If not provided, a local Fluentd instance will be called.                                                      |          |
| --fluentd-port      | Fluent host port                                                                                                                     | 24224    |
| --fluentd-tag       | Set a custom Fluentd tag                                                                                                             | 'test'   |
| --fluentd-label     | Set a custom Fluentd label                                                                                                           | 'pytest' |
| --fluentd-timestamp | Specify a Fluentd timestamp                                                                                                          | None     |
| --extend-logging    | Extend the Python logging with a Fluent handler                                                                                      | False    |
| --add-docstrings    | Add test docstrings to testcase call messages                                                                                        |          |
| --stage-settings    | Use custom stage settings file. See [documentation](https://pytest-fluent.readthedocs.io/en/latest/usage.html#custom-stage-settings) |          |

### Ini Configuration Support

Default values of the CLI arguments for a project could also be defined in one of the following ini configuration files:

1. `pytest.ini`: Arguments are defined under the `pytest` section in the file. This file takes precedence over all other configuration files even if it's empty.

```python
[pytest]
addopts= --session-uuid="ac2f7600-a079-46cf-a7e0-6408b166364c" --fluentd-port=24224  --fluentd-host=localhost --fluentd-tag='dummytest' --fluentd-label='pytest' --extend-logging
```

2. `pyproject.toml`: are considered for configuration when they contain a `tool.pytest.ini_options` section is available

```python
[tool.pytest.ini_options]
addopts="--fluentd-port=24224 --fluentd-host=localhost --fluentd-tag='test' --fluentd-label='pytest' --extend-logging"
```

3. `tox.ini`: can also be used to hold pytest configuration if they have a [pytest] section.

```python
[pytest]
addopts= --fluentd-port=24224 --fluentd-host=localhost --fluentd-tag='test' --fluentd-label='pytest'
```

If the same option is specified in both CLI and _ini_ file, then CLI option would have higher priority and override the _ini_ file values.

### What data are sent?

_pytest-fluent_ sends any information, e.g. stage information or logging from a test case, as a single chunk. For instance, the data collection from `test_addoptions.py` test looks as following

```json
[
    {
        "status": "start",
        "stage": "session",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0"
    },
    {
        "status": "start",
        "stage": "testcase",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0",
        "name": "test_fluentd_logged_parameters.py::test_base"
    },
    {
        "type": "logging",
        "host": "myComputer",
        "where": "test_fluentd_logged_parameters.test_base",
        "level": "INFO",
        "stack_trace": "None",
        "message": "Logged from test_base",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0",
        "stage": "testcase"
    },
    {
        "type": "logging",
        "host": "myComputer",
        "where": "test_fluentd_logged_parameters.test_base",
        "level": "INFO",
        "stack_trace": "None",
        "message": "Logged from test_base",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0",
        "stage": "testcase"
    },
    {
        "name": "test_fluentd_logged_parameters.py::test_base",
        "outcome": "passed",
        "duration": 0.0013457999999999526,
        "markers": {
            "test_base": 1,
            "test_fluentd_logged_parameters.py": 1,
            "test_fluentd_logged_parameters0": 1
        },
        "stage": "testcase",
        "when": "call",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0"
    },
    {
        "status": "finish",
        "stage": "testcase",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0",
        "name": "test_fluentd_logged_parameters.py::test_base"
    },
    {
        "status": "finish",
        "duration": 0.00297708511352539,
        "stage": "session",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0"
    }
]
```

whereat each object in the array is sent independently via _Fluentd_.

### Specifying a timestamp

Timestamps are added to the information if the ``--fluentd-timestamp`` option is enabled:

```python
[pytest]
addopts= --session-uuid="ac2f7600-a079-46cf-a7e0-6408b166364c" --fluentd-port=24224  --fluentd-host=localhost --fluentd-tag='dummytest' --fluentd-label='pytest' --fluentd-timestamp='@timestamp' --extend-logging
```

The timestamp is added to each message. The value is in ISO 8601 format. A sample
of the data collection from `test_addoptions.py` (as above) would look as below:

```json
[
    {
        "status": "start",
        "stage": "session",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "@timestamp": "2022-12-25T03:00:00.000000Z"
    },
    {
        "status": "start",
        "stage": "testcase",
        "sessionId": "d8f01de3-8416-4801-9406-0ea3d5cfe3c0",
        "testId": "6b444275-4450-4eff-b5d9-8355f0f99ab0",
        "name": "test_fluentd_logged_parameters.py::test_base",
        "@timestamp": "2022-12-25T03:00:00.100000Z"
    }
]
```

## Changelog

The changelog.

## Contributing

We welcome any contributions, enhancements, and bug-fixes. Open an [issue](https://github.com/Rohde-Schwarz/pytest-fluent/issues) on [Github](https://github.com) and [submit a pull request](https://github.com/Rohde-Schwarz/pytest-fluent/pulls).