Global Config Spec

[jcooklin]

NOTE by @mjbrender: snap was originally nicknamed pulse, which is why you'll see the Pulse used below

Global Config

This spec describes adding global configuration to pulse. We will describe two types of config below. The first is the top level configuration and will be referred to as Global Config while the second is specific to providing plugin configuration at load time and will be referred to going forward as Global Plugin Config. The pulse agent can be provided these configurations through a switch and configuration file at startup or through the API (pulsectl) after starting.

Example usage

pulsed -config ~/pulsed.cfg

~/pulsed.cfg

{
    "control": {
        "cache_ttl": "5s"
    },
    "scheduler": {
        "default_deadline": "5s",
        "worker_pool_size": 5
    },
    "plugin": {
        "all": {
            "password": "p@ssw0rd"
        },
        "collector": {
            "pcm": {
                "path": "/usr/local/pcm/bin",
                "versions": {
                    "1": {
                        "user": "john"
                    }
                }
            }
        }, 
        "publisher": {
            "influxdb": {
                "server": "xyz.local",
                "password": "$password"
            }
        }
    }
}

API/client usage

pulsectl config --control cache_ttl 5s
pulsectl config --scheduler cache_deadline 5s
pulsectl config --collector pcm.path /usr/local/bin
pulsectl config --control --unset cache_ttl 

Global Config provides runtime configuration and the ability to define a variable once and reference it in multiple plugins.

A ConfigPolicy derived from the Global Config (and Global Plugin Config) will be passed to the method GetMetricTypes. The Publish, Collect or Process methods will continue to receive ConfigPolicy but it will now be a merge between the tasks configuration and the Global Configuration.

[sandlbn]

@jcooklin Do you know when this will be implemented ? For one of my plugins I need to pass list with hypervisor URIs. Right now I have my own code but I will be happy to use global configuration module.

[lynxbat]

I don't think switch elements for pulsed should mix into globals.

instead:

{
    "global": {
        "password": "p@ssw0rd"
    },
    "cache_ttl": "5s",
    "default_deadline": "5s",
    "plugin": {
        "collector": {
            "pcm": {
                "path": "/usr/local/pcm/bin",
                "versions": {
                    "1": {
                        "user": "john"
                    }
                }
            }
        }, 
        "publisher": {
            "influxdb": {
                "server": "xyz.local",
                "password": "$password"
            }
        }
    }
}

[pittma]

what about

{
    "control": {
        "cache_ttl": "5s"
    },
    "scheduler": {
        "default_deadline": "5s",
        "worker_pool_size": 5
    },
    "plugin": {
        "all": {
            "password": "p@ssw0rd"
        },
        "collector": {
            "pcm": {
                "path": "/usr/local/pcm/bin",
                "versions": {
                    "1": {
                        "user": "john"
                    }
                }
            }
        },
        "publisher": {
            "influxdb": {
                "server": "xyz.local",
                "password": "$password"
            }
        }
    }
}

[lynxbat]

I like but why "global"?

[lynxbat]

Config is config for the pulsed

[lynxbat]

Or at least put under roles for each role config:

1. scheduler
2. control

[pittma]

word, agreed. +1 on:

Or at least put under roles for each role config:

1. scheduler
2. control

[jcooklin]

@sandlbn I'm working on it this sprint.

[jcooklin]

@lynxbat, @danielscottt: I updated ~/pulsed.cfg above based on the feedback. Additional thoughts?

[pittma]

Reopening this, the ability to configure the daemon is not yet implemented.

[geauxvirtual]

Closing with the merge of #763.