config.go

package config

import (
	"github.com/kelseyhightower/envconfig"
	"time"
)

type Config struct {
	// The time interval between 2 consecutive runs of the autoscaler.
	// Value can be any string parseable by time.ParseDuration()
	ProbeInterval time.Duration `default:"30s" split_words:"true"`

	// Valid values are "text" and "json"
	LogFormat string `default:"json" split_words:"true"`

	// Allows running the app in debug mode for development environments
	Debug bool `default:"false"`

	// If true, the app runs in DRY mode. Only the plan phase is run.
	// The final scaling plan generated is logged and no actual changes
	// are made to the infrastructure.
	Dry bool `default:"false"`

	Build struct {
		// The maximum duration for which a build is allowed to be in
		// pending state. Once the build has crossed this threshold,
		// autoscaler ignores it while generating scaling plans.
		// This helps avoid scaling behavior change when drone builds
		// are stuck in pending state.
		// A negative value indicates that there is no upper limit on
		// the duration of a pending build.
		PendingMaxDuration time.Duration `envconfig:"DRONE_BUILD_PENDING_MAX_DURATION" default:"-1s"`

		// The maximum duration for which a build is allowed to be in
		// running state. Once the build has crossed this threshold,
		// autoscaler ignores it while generating scaling plans.
		// This helps avoid scaling behavior change when drone builds
		// are stuck in running state.
		// A negative value indicates that there is no upper limit on
		// the duration of a running build.
		RunningMaxDuration time.Duration `envconfig:"DRONE_BUILD_RUNNING_MAX_DURATION" default:"-1s"`
	}

	Agent struct {
		// Minimum amount of time for which an Agent node should've been
		// up before it can be considered for destruction during downscaling.
		// This avoids accidentally deleting an agent that's not running
		// any workloads only because it was provisioned very recently
		MinRetirementAge time.Duration `envconfig:"DRONE_AGENT_MIN_RETIREMENT_AGE" default:"10m"`

		// Max number of builds that can run on an agent at any point
		// of time
		MaxBuilds int `envconfig:"DRONE_AGENT_MAX_BUILDS" required:"true"`

		// Minimum number of agents to maintain in the cluster,
		// regardless of the number of builds running
		MinCount int `envconfig:"DRONE_AGENT_MIN_COUNT" default:"1"`

		// Name of the AWS autoscaling group containing agent nodes
		AutoscalingGroup string `envconfig:"DRONE_AGENT_AUTOSCALING_GROUP" required:"true"`
	}

	// Information about the Drone server the app will talk to
	Server struct {
		Proto     string `envconfig:"DRONE_SERVER_PROTO" default:"http"`
		Host      string `envconfig:"DRONE_SERVER_HOST" required:"true"`
		AuthToken string `envconfig:"DRONE_SERVER_AUTH_TOKEN" required:"true"`
	}
}

func Load() (Config, error) {
	conf := Config{}
	err := envconfig.Process("SCALER", &conf)
	return conf, err
}