storyboard: decouple from experiment

+ Node no longer has "client" attribute
+ Client has a "nodes" attribute instead
+ servers, server nodes and the experiment can be added
  to a storyboard after instantiation to allow reuse of a SB
+ moved storyboard machinery to a separate module rumba.storyboard

1 files changed, 306 insertions, 0 deletions

diff --git a/rumba/storyboard.py b/rumba/storyboard.py
new file mode 100644
index 0000000..8c73422
--- /dev/null
+++ b/rumba/storyboard.py
@@ -0,0 +1,306 @@
+#
+# A library to manage ARCFIRE experiments
+#
+#    Copyright (C) 2017 Nextworks S.r.l.
+#    Copyright (C) 2017 imec
+#
+#    Sander Vrijders   <sander.vrijders@ugent.be>
+#    Vincenzo Maffione <v.maffione@nextworks.it>
+#    Marco Capitani    <m.capitani@nextworks.it>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., http://www.fsf.org/about/contact/.
+#
+
+# Base class for client programs
+#
+# @ap: Application Process binary
+# @options: Options to pass to the binary
+#
+import random
+import time
+
+import rumba.model as model
+import rumba.ssh_support as ssh_support
+import rumba.log as log
+
+logger = log.get_logger(__name__)
+
+try:
+    from numpy.random import poisson
+    from numpy.random import exponential
+    logger.debug("Using numpy for faster and better random variables.")
+except ImportError:
+    from rumba.recpoisson import poisson
+
+    def exponential(mean_duration):
+        return random.expovariate(1.0 / mean_duration)
+
+    logger.debug("Falling back to simple implementations.")
+    # PROBLEM! These logs will almost never be printed... But we might not care
+
+
+class Client(object):
+    def __init__(self, ap, nodes=None, options=None):
+        self.ap = ap
+        self.options = options
+        if isinstance(nodes, model.Node):
+            nodes = [nodes]
+        if nodes is None:
+            nodes = []
+        self.nodes = nodes
+
+    def add_node(self, node):
+        if not isinstance(node, model.Node):
+            raise Exception("A Node is required.")
+        self.nodes.append(node)
+
+    def process(self, duration):
+        node = random.choice(self.nodes) if len(self.nodes) > 0 else None
+        return ClientProcess(self.ap, duration, node, self.options)
+
+
+# Base class for client processes
+#
+# @ap: Application Process binary
+# @duration: The time (in seconds) this process should run
+# @start_time: The time at which this process is started.
+# @options: Options to pass to the binary
+#
+class ClientProcess(Client):
+    def __init__(self, ap, duration, node=None, options=None):
+        super(ClientProcess, self).__init__(ap, node, options=options)
+        self.duration = duration
+        self.start_time = None
+        self.running = False
+        self.node = node
+        self.pid = None
+
+    def run(self, node=None):
+        self.node = node
+        if self.node is None:
+            raise Exception('No node specified for client %s' % (self.ap,))
+        self.start_time = time.time()
+
+        logger.debug(
+            'Starting client app %s on node %s with duration %s.',
+            self.ap, self.node.name, self.duration
+        )
+
+        opt_str = self.options if self.options is not None else ""
+        cmd = "./startup.sh %s %s" % (self.ap, opt_str)
+        self.running = True
+        try:
+            self.pid = self.node.execute_command(cmd)
+        except ssh_support.SSHException:
+            logger.warning('Could not start client %s on node %s.',
+                           self.ap, self.node.name)
+        logger.debug('Client app %s on node %s got pid %s.',
+                     self.ap, self.node.name, self.pid)
+
+    def stop(self):
+        logger.debug(
+            'Killing client %s on node %s.',
+            self.ap, self.node.name
+        )
+        try:
+            self.node.execute_command("kill %s" % self.pid)
+        except ssh_support.SSHException:
+                logger.warn('Could not kill client %s on node %s.',
+                            self.ap, self.node.name)
+
+    def check(self):
+        """Check if the process should keep running, stop it if not,
+        and return true if and only if it is still running."""
+        now = time.time()
+        if not self.running:
+            return False
+        if now - self.start_time >= self.duration:
+            self.stop()
+            self.running = False
+            return False
+        return True
+
+
+# Base class for server programs
+#
+# @ap: Application Process binary
+# @arrival_rate: Average requests/s to be received by this server
+# @mean_duration: Average duration of a client connection (in seconds)
+# @options: Options to pass to the binary
+# @max_clients: Maximum number of clients to serve
+# @clients: Client binaries that will use this server
+# @nodes: Specific nodes to start this server on
+#
+class Server:
+    def __init__(self, ap, arrival_rate, mean_duration,
+                 options=None, max_clients=float('inf'),
+                 clients=None, nodes=None):
+        self.ap = ap
+        self.options = options if options is not None else ""
+        self.max_clients = max_clients
+        if clients is None:
+            clients = list()
+        self.clients = clients
+        self.nodes = nodes
+        self.arrival_rate = arrival_rate  # mean requests/s
+        self.mean_duration = mean_duration  # in seconds
+        self.pids = {}
+
+    def add_client(self, client):
+        self.clients.append(client)
+
+    def del_client(self, client):
+        self.clients.remove(client)
+
+    def add_node(self, node):
+        self.nodes.append(node)
+
+    def del_node(self, node):
+        self.nodes.remove(node)
+
+    def get_new_clients(self, interval):
+        """
+        Returns a list of clients of size appropriate to the server's rate.
+
+        The list's size should be a sample from Poisson(arrival_rate) over
+        interval seconds.
+        Hence, the average size should be interval * arrival_rate.
+        """
+        number = poisson(self.arrival_rate * interval)
+        number = int(min(number, self.max_clients))
+        return [self.make_client_process() for _ in range(number)]
+
+    def make_client_process(self):
+        """Returns a client of this server"""
+        if len(self.clients) == 0:
+            raise Exception("Server %s has empty client list." % (self,))
+        duration = exponential(self.mean_duration)
+        return random.choice(self.clients).process(duration=duration)
+
+    def run(self):
+        for node in self.nodes:
+            opt_str = self.options
+            logfile = "%s_server.log" % self.ap
+            script = r'nohup "$@" > %s & echo "$!"' % (logfile,)
+            cmds = ["echo '%s' > startup.sh && chmod a+x startup.sh"
+                    % (script,),
+                    "./startup.sh %s %s" % (self.ap, opt_str)]
+            logger.debug(
+                'Starting server %s on node %s with logfile %s.',
+                self.ap, node.name, logfile
+            )
+            try:
+                self.pids[node] = (node.execute_commands(cmds))
+            except ssh_support.SSHException:
+                logger.warn('Could not start server %s on node %s.',
+                            self.ap, node.name)
+
+    def stop(self):
+        for node, pid in self.pids.items():
+            logger.debug(
+                'Killing server %s on node %s.',
+                self.ap, node.name
+            )
+            try:
+                node.execute_command("kill %s" % pid)
+            except ssh_support.SSHException:
+                logger.warn('Could not kill server %s on node %s.',
+                            self.ap, node.name)
+
+
+# Base class for ARCFIRE storyboards
+#
+# @experiment: Experiment to use as input
+# @duration: Duration of the whole storyboard
+# @servers: App servers available in the network.
+#           Type == Server or Type == List[Tuple[Server, Node]]
+#
+class StoryBoard:
+
+    DEFAULT_INTERVAL = 2.5  # in seconds (may be a float)
+
+    def __init__(self, duration, experiment=None, servers=None):
+        self.experiment = experiment
+        self.duration = duration
+        self.servers = list()
+        if servers is None:
+            servers = list()
+        for s in servers:
+            self._validate_and_add_server(s)
+        self.active_clients = []
+        self.start_time = None
+
+    def _validate_and_add_server(self, s):
+        if self.experiment is None:
+            raise ValueError("Cannot add a server before "
+                             "setting the experiment.")
+        if hasattr(s, '__len__') and len(s) == 2:
+            server, node = s
+            if not isinstance(server, Server) or not isinstance(node, model.Node):
+                raise TypeError('First element must be of "Server" type, '
+                                'second must be of "Node" type.')
+            server.add_node(node)
+            self.servers.append(server)
+        elif type(s) == Server:
+            self.servers.append(s)
+        else:
+            raise TypeError('Input servers should be either an object of '
+                            '"Server" type or a Server-Node couple.')
+        for node in self.servers[-1].nodes:
+            if node not in self.experiment.nodes:
+                raise ValueError('Cannot run server on node %s, '
+                                 'not in experiment.' % (node.name,))
+
+    def set_experiment(self, experiment):
+        if not isinstance(experiment, model.Experiment):
+            raise TypeError('Experiment instance required.')
+        self.experiment = experiment
+
+    def add_server(self, server):
+        self._validate_and_add_server(server)
+
+    def del_server(self, server):
+        self.servers.remove(server)
+
+    def start(self):
+        self.start_time = time.time()
+        script = r'nohup "$@" > /tmp/ & echo "$!"'
+        logger.debug("Writing utility startup script on client nodes.")
+        for server in self.servers:
+            for client in server.clients:
+                for node in client.nodes:
+                    node.execute_command(
+                        "echo '%s' > startup.sh && chmod a+x startup.sh" % (script,)
+                    )
+        try:
+            for server in self.servers:
+                server.run()
+            while time.time() - self.start_time < self.duration:
+                for server in self.servers:
+                    clients = server.get_new_clients(self.DEFAULT_INTERVAL)
+                    for new_client in clients:
+                        new_client.run()
+                        self.active_clients.append(new_client)
+                surviving = []
+                for x in self.active_clients:
+                    if x.check():
+                        surviving.append(x)
+                self.active_clients = surviving
+                time.sleep(self.DEFAULT_INTERVAL)
+        finally:
+            for client in self.active_clients:
+                client.stop()
+            for server in self.servers:
+                server.stop()