Metadata-Version: 2.1
Name: pop-evbus
Version: 1
Summary: An asynchronous message ingress system
Home-page: https://gitlab.com/saltstack/pop/evbus
Author: Tyler Johnson
Author-email: tyjohnson@vmware.com
License: UNKNOWN
Description: =====
        EVBUS
        =====
        
        An asynchronous message ingress system.
        Messages that are put onto the event bus are "vomited" to all the ingress plugin publishers.
        
        INSTALLATION
        ============
        
        .. code-block:: bash
        
            pip install pop-evbus
        
        USAGE
        =====
        
        `evbus` is mainly an app-merge component for larger projects.
        However, it includes a script that can be useful for testing your ingress queues.
        This testing script can randomly generate data and put it on the event bus -- which gets propagated to the ingress publishers.
        A listener iterates over the internal ingress queue and prints everything that gets posted to it.
        The the outputter to format the printed data can be specified with `--output`.
        The `--random` flag starts a coroutine that periodically populates the event bus with random data.
        
        .. code-block:: bash
        
            evbus_test --output json --random
        
        TESTING
        =======
        
        Install `evbus` locally with testing libraries:
        
        .. code-block:: bash
        
            $ git clone git@gitlab.com:saltstack/pop/evbus.git
            $ pip install -e evbus -r requirements-test.txt
        
        If you have a rabbitmq-server binary installed via your system's package manager, the pika tests won't be skipped.
        Start a local rabbitmq-server with the default parameters:
        
        .. code-block:: bash
        
            rabbitmq-server
        
        Run the tests with pytest:
        
        .. code-block:: bash
        
            $ pytest evbus/tests
        
        
        ACCT PROFILES
        =============
        
        `evbus` will read credentials that are encrypted using the `acct` system.
        To use this system, create a yaml file that has the plaintext credentials and information needed
        to connect with the various ingress plugins.
        For example, to connect to a rabbitmq server, or any amqp implementation,
        have a profile in your `acct` credentials file that specifies the "pika" acct plugin:
        
        credentials.yml
        
        .. code-block:: yaml
        
            pika:
              profile_name:
                host: localhost
                port: 5672
                username: XXXXXXXXXXXX
                password: XXXXXXXXXXXX
                ingress_channels:
                  - channel1
                  - channel2
        
        Next use the `acct` command to encrypt this file using the fernet algorithm:
        
        .. code-block:: bash
        
            $ acct credentials.yml
            New encrypted file created at: credentials.yml.fernet
            The file was encrypted with this key:
            YeckEnWEGOjBDVxxytw13AsdLgquzhCtFHOs7kDsna8=
        
        The `acct` information can now be stored in environment variables:
        
        .. code-block:: bash
        
            $ export ACCT_FILE = $PWD/credentials.yml.fernet
            $ export ACCT_KEY = "YeckEnWEGOjBDVxxytw13AsdLgquzhCtFHOs7kDsna8="
        
        They can also be used on the command line:
        
        .. code-block:: bash
        
            $ evbus_test --acct-file=credentials.yml.fernet --acct-key="YeckEnWEGOjBDVxxytw13AsdLgquzhCtFHOs7kDsna8="
        
        
        INTEGRATION
        ===========
        
        Your own app can extend `acct`'s command line interface to use the `--acct-file` and `--acct-key` options for evbus:
        
        my_project/conf.py
        
        .. code-block:: python
        
            CLI_CONFIG = {
                "acct_file": {"source": "acct", "os": "ACCT_FILE"},
                "acct_key": {"source": "acct", "os": "ACCT_KEY"},
                "ingress_profiles": {"source": "evbus"},
            }
        
        
        In your own project, you can vertically merge `evbus` and extend it with your own ingress plugins:?
        
        my_project/conf.py
        
        .. code-block:: python
        
            DYNE = {
                "my_project": ["my_project"],
                "evbus": ["evbus"],
                "acct": ["acct"],
            }
        
        Create the directory `my_project/ingress` and add your ingress plugins there.
        
        ingress plugins need a function called "publish" that takes a parameter called "event"
        
        my_project/ingress/my_plugin.py
        
        .. code-block:: python
        
            async def publish(hub, event):
                await my_queue.put(event)
        
        The publish function can optionally have a `ctx` parameter if your ingress plugin requires login credentials.
        The `ctx` parameter will be automatically be populated by `acct`  and `evbus` if a profile that specifies your
        plugin is included in the encrypted acct file.
        
        my_project/ingress/my_plugin.py
        
        .. code-block:: python
        
            async def publish(hub, ctx, event):
                for channel in ctx.channels:
                    probably_an_exchange_object = await ctx.connection.some_func(channel)
                    await probably_an_exchange_object.publish_function(event)
        
        Create the directory  `my_project/acct/evbus` and add your acct plugins there.
        `acct` plugins need to implement a `gather` function, which reads the appropriate information from
        `hub.acct.PROFILES` and turns it into processed profile information in `hub.acct.SUB_PROFILES`.
        This processing can include operations such as opening a connection to a remote server.
        
        my_project/acct/evbus/my_plugin.py
        
        .. code-block:: python
        
                async def gather(hub):
                    """
                    Get [my_plugin] profiles from an encrypted file
        
                    Example:
        
                    .. code-block:: yaml
        
                        my_plugin:
                          profile_name:
                            host: localhost
                            port: 12345
                            username: XXXXXXXXXXXX
                            password: XXXXXXXXXXXX
                            ingress_channels:
                              - channel1
                              - channel2
                    """
                    sub_profiles = {}
                    for profile, ctx in hub.acct.PROFILES.get("my_plugin", {}).items():
                        # Create a connection through [some_library] for each of the profiles
                        sub_profiles[profile] = {
                            "connected": False,
                            "connection": await some_library.connect(**ctx),
                            "channels": ctx.pop("ingress_channels", []),
                        }
                    # Return these to be automatically processed by acct and injected into the `ctx` parameter of appropriate ingress publish calls.
                    return sub_profiles
        
        
        Add evbus startup code to your project's initializer:
        
        my_project/my_project/init.py
        
        .. code-block:: python
        
            def __init__(hub):
                # Horizontally merge the evbus dynamic namespace into your project
                hub.pop.sub.add(dyne_name="evbus")
        
            def cli(hub):
                # Load the config from evbus onto hub.OPT
                hub.pop.config.load(["my_project", "evbus"], cli="my_project")
        
                # Create the asyncio loop
                hub.pop.loop.create()
        
                # Create the event bus coroutine
                coro = hub.evbus.init.start(
                    acct_file=hub.OPT.acct.acct_file,
                    acct_key=hub.OPT.acct.acct_key,
                    ingress_profiles=hub.OPT.evbus.ingress_profiles,
                )
        
                # Start the event bus
                hub.pop.Loop.run_until_complete(coro)
        
Platform: UNKNOWN
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Development Status :: 5 - Production/Stable
Requires-Python: >=3.6
Description-Content-Type: text/x-rst
