asteris-llc/converge

// Copyright © 2016 Asteris, LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package unit

import (
    "path"
    "strings"
)

// UnitType provides an enumeration over the different types of systemd unit
// file types
type UnitType uint

const (
    // UnitTypeUnknown represents a generic or unknown unit type
    UnitTypeUnknown UnitType = iota

    // UnitTypeService represents a systemd.service(5)
    UnitTypeService UnitType = iota

    // UnitTypeSocket represents a systemd.socket(5)
    UnitTypeSocket UnitType = iota

    // UnitTypeDevice represents a systemd.device(5)
    UnitTypeDevice UnitType = iota

    // UnitTypeMount represents a systemd.mount(5)
    UnitTypeMount UnitType = iota

    // UnitTypeAutoMount represents a systemd.automount(5)
    UnitTypeAutoMount UnitType = iota

    // UnitTypeSwap represents a systemd.swap(5)
    UnitTypeSwap UnitType = iota

    // UnitTypeTarget represents a systemd.target(5)
    UnitTypeTarget UnitType = iota

    // UnitTypePath represents a systemd.path(5)
    UnitTypePath UnitType = iota

    // UnitTypeTimer represents a systemd.timer(5)
    UnitTypeTimer UnitType = iota

    // UnitTypeSnapshot represents a systemd.snapshot(5)
    UnitTypeSnapshot UnitType = iota

    // UnitTypeSlice represents a systemd.slice(5)
    UnitTypeSlice UnitType = iota

    // UnitTypeScope represents a systemd.scope(5)
    UnitTypeScope UnitType = iota
)

// UnitTypeFromName takes a service name in the form of "foo.service" and
// returns an appropriate UnitType representing that service type. If the
// service type isn't recognized from the suffix then UnitTypeUnknown is
// returned.
func UnitTypeFromName(s string) UnitType {
    basename := path.Base(s)
    components := strings.Split(basename, ".")
    if len(components) == 0 {
        return UnitTypeUnknown
    }
    switch strings.ToLower(components[len(components)-1]) {
    case "service":
        return UnitTypeService
    case "socket":
        return UnitTypeSocket
    case "device":
        return UnitTypeDevice
    case "mount":
        return UnitTypeMount
    case "automount":
        return UnitTypeAutoMount
    case "swap":
        return UnitTypeSwap
    case "target":
        return UnitTypeTarget
    case "path":
        return UnitTypePath
    case "timer":
        return UnitTypeTimer
    case "snapshot":
        return UnitTypeSnapshot
    case "slice":
        return UnitTypeSlice
    case "scope":
        return UnitTypeScope
    }
    return UnitTypeUnknown
}

// Suffix is the dual of UnitTypeFromName and generates the correct unit file
// suffix based on the type
func (u UnitType) Suffix() string {
    switch u {
    case UnitTypeService:
        return "service"
    case UnitTypeSocket:
        return "socket"
    case UnitTypeDevice:
        return "device"
    case UnitTypeMount:
        return "mount"
    case UnitTypeAutoMount:
        return "automount"
    case UnitTypeSwap:
        return "swap"
    case UnitTypeTarget:
        return "target"
    case UnitTypePath:
        return "path"
    case UnitTypeTimer:
        return "timer"
    case UnitTypeSnapshot:
        return "snapshot"
    case UnitTypeSlice:
        return "slice"
    case UnitTypeScope:
        return "scope"
    }
    return ""
}

// String provides a stringified-version of the type
func (u UnitType) String() string {
    return u.Suffix()
}

// UnitTypeString returns a stringified version of the unit type, in title case
func (u UnitType) UnitTypeString() string {
    return strings.Title(u.Suffix())
}

// HasProperties returns true if the unit type has type-specific properties
func (u UnitType) HasProperties() bool {
    switch u {
    case UnitTypeTarget, UnitTypeSnapshot, UnitTypeUnknown:
        return false
    }
    return true
}