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pymongo_inmemory

A mongo mocking library with an ephemeral MongoDB running in memory.

What's new?

v0.2.10

• Updated MongoDB version list.
• With 6.0 versions, there is support of MacOS running on ARM arch.

Installation

pip install pymongo-inmemory

Usage

Configure

There are several ways you can configure pymongo_inmemory.

1. Insert a new section titled pymongo_inmemory to your project's setup.cfg version you want to spin up:

   [pymongo_inmemory]
   operating_system = ubuntu
   os_version = 18
   mongod_port = 27019

2. Define an ALL_CAPS environment variables with prefix PYMONGOIM__ (attention to trailing double underscores.) For instance, to override the port, set up an environment variable PYMONGOIM__MONGOD_PORT.

Import and use

pymongo_inmemory wraps the client class MongoClient that comes from pymongo and configures with an ephemeral MongoDB server. You can import this MongoClient from pymongo_inmemory instead of pymongo and use it to perform tests:

from pymongo_inmemory import MongoClient

client = MongoClient()  # No need to provide host
db = client['testdb']
collection = db['test-collection']
# etc., etc.
client.close()

# Also usable with context manager
with MongoClient() as client:
    # do stuff

Configuration

• *Note 1: Generic Linux version offering for MongoDB ends with version 4.0.23. If the operating system is just linux and if selected MongoDB version is higher, it will default to 4.0.23.
• **Note 2: URL bank is filled with URLs collected from release list and archived released list, so if a version is not in the bank you can use the same list to provide an official download link.

Available MongoDB versions

There is an internal URL bank that is filled with URLs collected from

• release list and
• archived released list

Below table is a summary of possible setting for operating_system, os_version and available MongoDB versions for them to set as mongo_version at major.minor level.

Note that, not all major.minor.patch level is available for all OS versions. For exact patch level range, either see release pages of MongoDB or have a look at the internal URL bank.

*Note: No need to specify generic, as it will be chosen automatically since it's the only version for that OS.

How do we determine which MongoDB to download?

There are two (three if it's a Linux flavour) bits of information we need to determine a MongoDB: operating system and MongoDB version.

Note: You can always set download_url to provide an exact URL to download from.

Operating System detection

Python has limited tools in its standard library to determine the exact version of the operating system and operating system version. pymongo_inmemory basically reads output of platform.system() to determine if underlying OS is Linux, MacOS or Windows.

For Windows and MacOS, it will download only one flavour of OS for a particular MongoDB version (64bit and, for Windows, Windows Server version if there is one.) However, Linux has many flavours. Up to MongoDB 4.0.23, a MongoDB for a generic Linux OS can still be downloaded, but for later versions of MongoDB, there are no such builds, hence you will need to explicitly set operating_system parameter if you want to use MongoDB versions higher than that.

Operating system detection behaviour of pymongo_inmemory might change in the future, if there is a demand for more magic, but for now we are keeping things simple.

Deciding MongoDB version

• If no version is provided, highest version of MongoDB for the operating system is selected.
• If only a major version is given, like 4, then highest minor.patch version is selected, like 4.4.4.
• If only major.minor version is given, like 4.0, then highest patch version is selected, like 4.0.23.
• If exact major.minor.patch version is given, like 4.0.22, then that version is selected.
• If patch version is not found. like 4.0.50, highest patch version is selected, like 4.0.23.
• If minor version is not found. like 3.90.50, highest minor.patch version is selected, like 3.6.22.
• If major version is not found. like 1.0.0, highest major.minor.patch version is selected, like 4.4.4.

Supported Python versions

Since few development tools only support Python version 3.6 and above, all testing and tooling done from that version up.

This also limits the minimum Python version of tested features. However there shouldn't be a hard limitation to use Python 3.5. We recommend upgrading older Python versions than that.

Development

Project is set up to develop with poetry. We rely on pyenv to maintain the minimum supported Python version.

After installing pyenv, poetry, and cloning the repo, create the shell and install all package requirements:

pyenv install --skip-existing
poetry install --no-root
poetry shell

Run the tests:

pytest

If on NIX systems you can run further tests:

bash tests/integrity/test_integrity.sh

Adding a new MongoDB version

Follow the guide here.

See how you can wet your feet

Check out good first issues.