This repository has been archived by the owner on Nov 30, 2021. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 798
/
unit.go
169 lines (154 loc) · 4.68 KB
/
unit.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
package fleet
import (
"fmt"
"io/ioutil"
"os"
"path"
"strconv"
"strings"
"github.com/coreos/fleet/unit"
)
// path hierarchy for finding systemd service templates
var templatePaths = []string{
os.Getenv("DEISCTL_UNITS"),
path.Join(os.Getenv("HOME"), ".deis", "units"),
"/var/lib/deis/units",
}
// and the same for systemd service "decorators" for optionally isolating
// control plane, data plane, and router mesh
var decoratorPaths = []string{
path.Join(os.Getenv("DEISCTL_UNITS"), "decorators"),
path.Join(os.Getenv("HOME"), ".deis", "units", "decorators"),
"/var/lib/deis/units/decorators",
}
// Units returns a list of units filtered by target
func (c *FleetClient) Units(target string) (units []string, err error) {
allUnits, err := c.Fleet.Units()
if err != nil {
return
}
// Look for units starting with the given target name first. If the given
// name starts with "deis-", this will easily locate platform components,
// but we search without canonicalizing the target name FIRST so we have the
// opportunity to locate application containers (whose containers do not
// adhere to the same naming convention as the platform's own components).
for _, u := range allUnits {
if strings.HasPrefix(u.Name, target) {
units = append(units, u.Name)
}
}
// If none are found, canonicalize the target string and search again. This
// will locate platform components that were referenced by a target string
// NOT already beginning with "deis-".
if len(units) == 0 {
canonTarget := strings.ToLower(target)
if !strings.HasPrefix(canonTarget, "deis-") {
canonTarget = "deis-" + canonTarget
}
for _, u := range allUnits {
if strings.HasPrefix(u.Name, canonTarget) {
units = append(units, u.Name)
}
}
}
// If still nothing is found, then we have an error on our hands.
if len(units) == 0 {
err = fmt.Errorf("could not find unit: %s", target)
}
return
}
// nextUnit returns the next unit number for a given component
func (c *FleetClient) nextUnit(component string) (num int, err error) {
units, err := c.Units(component)
if err != nil {
return
}
num, err = nextUnitNum(units)
if err != nil {
return
}
return
}
// lastUnit returns the last unit number for a given component
func (c *FleetClient) lastUnit(component string) (num int, err error) {
units, err := c.Units(component)
if err != nil {
return
}
num, err = lastUnitNum(units)
if err != nil {
return
}
return
}
// NewUnit takes a component type and returns a Fleet unit
// that includes the relevant systemd service template
func NewUnit(component string, templatePaths []string, decorate bool) (uf *unit.UnitFile, err error) {
template, err := readTemplate(component, templatePaths)
if err != nil {
return
}
if decorate {
decorator, err := readDecorator(component)
if err != nil {
return nil, err
}
uf, err = unit.NewUnitFile(string(template) + "\n" + string(decorator))
} else {
uf, err = unit.NewUnitFile(string(template))
}
return
}
// formatUnitName returns a properly formatted systemd service name
// using the given component type and number
func formatUnitName(component string, num int) (unitName string, err error) {
component = strings.TrimPrefix(component, "deis-")
if num == 0 {
return "deis-" + component + ".service", nil
}
return "deis-" + component + "@" + strconv.Itoa(num) + ".service", nil
}
// readTemplate returns the contents of a systemd template for the given component
func readTemplate(component string, templatePaths []string) (out []byte, err error) {
templateName := "deis-" + component + ".service"
var templateFile string
// look in $DEISCTL_UNITS env var, then the local and global root paths
for _, p := range templatePaths {
if p == "" {
continue
}
filename := path.Join(p, templateName)
if _, err := os.Stat(filename); err == nil {
templateFile = filename
break
}
}
if templateFile == "" {
return nil, fmt.Errorf("Could not find unit template for %v", component)
}
out, err = ioutil.ReadFile(templateFile)
if err != nil {
return
}
return
}
// readDecorator returns the contents of a file containing a snippet that can
// optionally be grafted on to the end of a corresponding systemd unit to
// achieve isolation of the control plane, data plane, and router mesh
func readDecorator(component string) (out []byte, err error) {
decoratorName := "deis-" + component + ".service.decorator"
var decoratorFile string
// look in $DEISCTL_UNITS env var, then the local and global root paths
for _, p := range decoratorPaths {
filename := path.Join(p, decoratorName)
if _, err := os.Stat(filename); err == nil {
decoratorFile = filename
break
}
}
if decoratorFile == "" {
return
}
out, err = ioutil.ReadFile(decoratorFile)
return
}