Service Deployment Configs
==========================

Each EI service has a deployment configuration, and we automate these via ``_EISvc`` class instances
that are used by an EI manager. Functions in these classes can be set to run on all nodes in an EI manager,
or instead take a specific node instance as an argument.

For example, take the ``PubSub`` service configuration:

.. code-block:: python

    class PubSub(_EISvc):
    SVCID = 3
    SVCNAME = "pubsub"

    def __init__(self, ei):
        super().__init__(ei)
        self.cores = [node for node in ei.nodes if node.sn == 3]

    @splat_node
    def config(self, *, node):
        ctl = QuickCtl(node)
        res = MiniFutureList()
        res.append(ctl.call('tree.add_child', 'config', './"services"/"pubsub"'))
        res.append(
            ctl.call('tree.add_child', 'config', './"services"/"pubsub"/"core_sn_id"')
        )
        res.append(
            ctl.call(
                'tree.write', 'config', './"services"/"pubsub"/"core_sn_id"', value=3
            )
        )
        return res

    @splat_node
    def start_proxy(self, *, node):
        return node.node.run(
            f'cd {node.node.pox_dir} ; ./pox.py misc.pidfile=/tmp/eilogs/pid_{node.dom}_{node.sn}_pubsub_proxy web --no-cookieguard --port={node.proxy_port(self.SVCID)} ei.pubsub.proxy --hssock={node.hssock} >&/dev/null &',
            asynchronous=True,
        )

The ``SVCID`` and ``SVCNAME`` variables must match what is in EI directly.
By defining the ``@splat_node`` decorator on the ``config(...)`` and ``start_proxy(...)`` functions, the
EI manager can run this function on all nodes:

.. code-block:: python

    ei.pubsub.config()
    ei.pubsub.start_proxy()
    node_mgr.wait_all()

The futures list in these functions will cause the commands added onto a node to be run in-order on that node;
each node has an asynchronous task manager to do this. Running ``wait_all()`` on a node manager will wait for
all commands on all nodes to complete before returning.

It is possible to write these functions without ``@splat_node``, in which case they must be called with
a service node instance:

.. code-block:: python

    ei.qbss.config(node=node_mgr.instance((1, 1)), ...)