core-extra/daemon/examples/myservices/sample.py

"""
Sample user-defined service.
"""

from core.service import CoreService
from core.service import ServiceMode


## Custom CORE Service
class MyService(CoreService):
    ### Service Attributes

    # Name used as a unique ID for this service and is required, no spaces.
    name = "MyService"
    # Allows you to group services within the GUI under a common name.
    group = "Utility"
    # Executables this service depends on to function, if executable is not on the path, service will not be loaded.
    executables = ()
    # Services that this service depends on for startup, tuple of service names.
    dependencies = ()
    # Directories that this service will create within a node.
    dirs = ()
    # Files that this service will generate, without a full path this file goes in the node's directory.
    # e.g. /tmp/pycore.12345/n1.conf/myfile
    configs = ("sh myservice1.sh", "sh myservice2.sh")
    # Commands used to start this service, any non-zero exit code will cause a failure.
    startup = ("sh %s" % configs[0], "sh %s" % configs[1])
    # Commands used to validate that a service was started, any non-zero exit code will cause a failure.
    validate = ()
    # Validation mode, used to determine startup success.
    # * NON_BLOCKING    - runs startup commands, and validates success with validation commands
    # * BLOCKING        - runs startup commands, and validates success with the startup commands themselves
    # * TIMER           - runs startup commands, and validates success by waiting for "validation_timer" alone
    validation_mode = ServiceMode.NON_BLOCKING
    # Time for a service to wait before running validation commands or determining success in TIMER mode.
    validation_timer = 0
    # Shutdown commands to stop this service.
    shutdown = ()

    ### On Load
    @classmethod
    def on_load(cls):
        # Provides a way to run some arbitrary logic when the service is loaded, possibly to help facilitate
        # dynamic settings for the environment.
        pass

    ### Get Configs
    @classmethod
    def get_configs(cls, node):
        # Provides a way to dynamically generate the config files from the node a service will run.
        # Defaults to the class definition and can be left out entirely if not needed.
        return cls.configs

    ### Generate Config
    @classmethod
    def generate_config(cls, node, filename):
        # Returns a string representation for a file, given the node the service is starting on the config filename
        # that this information will be used for. This must be defined, if "configs" are defined.
        cfg = "#!/bin/sh\n"

        if filename == cls.configs[0]:
            cfg += "# auto-generated by MyService (sample.py)\n"
            for ifc in node.netifs():
                cfg += 'echo "Node %s has interface %s"\n' % (node.name, ifc.name)
        elif filename == cls.configs[1]:
            cfg += "echo hello"

        return cfg

    ### Get Startup
    @classmethod
    def get_startup(cls, node):
        # Provides a way to dynamically generate the startup commands from the node a service will run.
        # Defaults to the class definition and can be left out entirely if not needed.
        return cls.startup

    ### Get Validate
    @classmethod
    def get_validate(cls, node):
        # Provides a way to dynamically generate the validate commands from the node a service will run.
        # Defaults to the class definition and can be left out entirely if not needed.
        return cls.validate