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util/structfs: import https://github.com/unistack-org/go-structfs #186

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vtolstov merged 1 commits from structfs into v3 2023-02-19 23:38:31 +03:00
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3
util/structfs/README.md Normal file
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# go-structfs
Expose struct data via http.FileServer

67
util/structfs/metadata_digitalocean.go Normal file
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package structfs
import (
"encoding/json"
"net/http"
"strings"
"time"
)
type DigitalOceanMetadata struct {
Metadata struct {
V1 struct {
DropletID int64 `json:"droplet_id"`
Hostname string `json:"hostname"`
VendorData string `json:"vendor_data"`
PublicKeys []string `json:"public_keys"`
Region string `json:"region"`
Interfaces struct {
Private []struct {
IPv4 struct {
Address string `json:"ip_address"`
Netmask string `json:"netmask"`
Gateway string `json:"gateway"`
}
Mac string `json:"mac"`
Type string `json:"type"`
} `json:"private"`
Public []struct {
IPv4 struct {
Address string `json:"ip_address"`
Netmask string `json:"netmask"`
Gateway string `json:"gateway"`
} `json:"ipv4"`
IPv6 struct {
Address string `json:"ip_address"`
CIDR int `json:"cidr"`
Gateway string `json:"gateway"`
} `json:"ipv6"`
Mac string `json:"mac"`
Type string `json:"type"`
} `json:"public"`
} `json:"interfaces"`
FloatingIP struct {
IPv4 struct {
Active bool `json:"active"`
} `json:"ipv4"`
} `json:"floating_ip"`
DNS struct {
Nameservers []string `json:"nameservers"`
} `json:"dns"`
Features map[string]interface{} `json:"features"`
} `json:"v1"`
} `json:"metadata"`
}
func (stfs *DigitalOceanMetadata) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch r.URL.Path {
case "/metadata/v1.json":
json.NewEncoder(w).Encode(stfs.Metadata.V1)
default:
fs := FileServer(stfs, "json", time.Now())
idx := strings.Index(r.URL.Path[1:], "/")
r.URL.Path = strings.Replace(r.URL.Path[idx+1:], "/metadata/v1/", "", 1)
r.RequestURI = r.URL.Path
fs.ServeHTTP(w, r)
}
}

30
util/structfs/metadata_ec2.go Normal file
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package structfs
type EC2Metadata struct {
Latest struct {
Metadata struct {
AMIID int `json:"ami-id"`
AMILaunchIndex int `json:"ami-launch-index"`
AMIManifestPath string `json:"ami-manifest-path"`
AncestorAMIIDs []int `json:"ancestor-ami-ids"`
BlockDeviceMapping []string `json:"block-device-mapping"`
InstanceID int `json:"instance-id"`
InstanceType string `json:"instance-type"`
LocalHostname string `json:"local-hostname"`
LocalIPv4 string `json:"local-ipv4"`
kernelID int `json:"kernel-id"`
Placement string `json:"placement"`
AvailabilityZone string `json:"availability-zone"`
ProductCodes string `json:"product-codes"`
PublicHostname string `json:"public-hostname"`
PublicIPv4 string `json:"public-ipv4"`
PublicKeys []struct {
Key []string `json:"-"`
} `json:"public-keys"`
RamdiskID int `json:"ramdisk-id"`
ReservationID int `json:"reservation-id"`
SecurityGroups []string `json:"security-groups"`
} `json:"meta-data"`
Userdata string `json:"user-data"`
} `json:"latest"`
}

245
util/structfs/structfs.go Normal file
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package structfs
import (
"fmt"
"io"
"net/http"
"os"
"reflect"
"strings"
"time"
)
// FileServer creates new file server from the struct iface with specific tag and specific modtime
func FileServer(iface interface{}, tag string, modtime time.Time) http.Handler {
if modtime.IsZero() {
modtime = time.Now()
}
return &fs{iface: iface, tag: tag, modtime: modtime}
}
func (fs *fs) ServeHTTP(w http.ResponseWriter, r *http.Request) {
upath := r.URL.Path
if !strings.HasPrefix(upath, "/") {
upath = "/" + upath
r.URL.Path = upath
}
f, err := fs.Open(r.URL.Path)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(err.Error()))
return
}
w.Header().Set("Content-Type", "application/octet-stream")
http.ServeContent(w, r, r.URL.Path, fs.modtime, f)
}
type fs struct {
iface interface{}
tag string
modtime time.Time
}
type file struct {
name string
offset int64
data []byte
modtime time.Time
}
type fileInfo struct {
name string
size int64
modtime time.Time
}
func (fi *fileInfo) Sys() interface{} {
return nil
}
func (fi *fileInfo) Size() int64 {
return fi.size
}
func (fi *fileInfo) Name() string {
return fi.name
}
func (fi *fileInfo) Mode() os.FileMode {
if strings.HasSuffix(fi.name, "/") {
return os.FileMode(0755) | os.ModeDir
}
return os.FileMode(0644)
}
func (fi *fileInfo) IsDir() bool {
// disables additional open /index.html
return false
}
func (fi *fileInfo) ModTime() time.Time {
return fi.modtime
}
func (f *file) Close() error {
return nil
}
func (f *file) Read(b []byte) (int, error) {
var err error
var n int
if f.offset >= int64(len(f.data)) {
return 0, io.EOF
}
if len(f.data) > 0 {
n = copy(b, f.data[f.offset:])
}
if n < len(b) {
err = io.EOF
}
f.offset += int64(n)
return n, err
}
func (f *file) Readdir(count int) ([]os.FileInfo, error) {
return nil, nil
}
func (f *file) Seek(offset int64, whence int) (int64, error) {
// log.Printf("seek %d %d %s\n", offset, whence, f.name)
switch whence {
case os.SEEK_SET:
f.offset = offset
case os.SEEK_CUR:
f.offset += offset
case os.SEEK_END:
f.offset = int64(len(f.data)) + offset
}
return f.offset, nil
}
func (f *file) Stat() (os.FileInfo, error) {
return &fileInfo{name: f.name, size: int64(len(f.data)), modtime: f.modtime}, nil
}
func (fs *fs) Open(path string) (http.File, error) {
return newFile(path, fs.iface, fs.tag, fs.modtime)
}
func newFile(name string, iface interface{}, tag string, modtime time.Time) (*file, error) {
var err error
f := &file{name: name, modtime: modtime}
f.data, err = structItem(name, iface, tag)
if err != nil {
return nil, err
}
return f, nil
}
func structItem(path string, iface interface{}, tag string) ([]byte, error) {
var buf []byte
var err error
var curiface interface{}
if path == "/" {
return getNames(iface, tag)
}
idx := strings.Index(path[1:], "/")
switch {
case idx > 0:
curiface, err = getStruct(path[1:idx+1], iface, tag)
if err != nil {
return nil, err
}
buf, err = structItem(path[idx+1:], curiface, tag)
case idx == 0:
return getNames(iface, tag)
case idx < 0:
return getValue(path[1:], iface, tag)
}
return buf, err
}
func getNames(iface interface{}, tag string) ([]byte, error) {
var lines []string
s := reflectValue(iface)
typeOf := s.Type()
for i := 0; i < s.NumField(); i++ {
value := typeOf.Field(i).Tag.Get(tag)
if value != "" {
lines = append(lines, value)
}
}
if len(lines) > 0 {
return []byte(strings.Join(lines, "\n")), nil
}
return nil, fmt.Errorf("failed to find names")
}
func getStruct(name string, iface interface{}, tag string) (interface{}, error) {
s := reflectValue(iface)
typeOf := s.Type()
for i := 0; i < s.NumField(); i++ {
if typeOf.Field(i).Tag.Get(tag) == name {
return s.Field(i).Interface(), nil
}
}
return nil, fmt.Errorf("failed to find iface %T with name %s", iface, name)
}
func getValue(name string, iface interface{}, tag string) ([]byte, error) {
s := reflectValue(iface)
typeOf := s.Type()
switch typeOf.Kind() {
case reflect.Map:
return []byte(fmt.Sprintf("%v", s.MapIndex(reflect.ValueOf(name)).Interface())), nil
default:
for i := 0; i < s.NumField(); i++ {
if typeOf.Field(i).Tag.Get(tag) != name {
continue
}
ifs := s.Field(i).Interface()
switch s.Field(i).Kind() {
case reflect.Slice:
var lines []string
for k := 0; k < s.Field(i).Len(); k++ {
lines = append(lines, fmt.Sprintf("%v", s.Field(i).Index(k)))
}
return []byte(strings.Join(lines, "\n")), nil
default:
return []byte(fmt.Sprintf("%v", ifs)), nil
}
}
}
return nil, fmt.Errorf("failed to find %s in interface %T", name, iface)
}
func hasValidType(obj interface{}, types []reflect.Kind) bool {
for _, t := range types {
if reflect.TypeOf(obj).Kind() == t {
return true
}
}
return false
}
func reflectValue(obj interface{}) reflect.Value {
var val reflect.Value
if reflect.TypeOf(obj).Kind() == reflect.Ptr {
val = reflect.ValueOf(obj).Elem()
} else {
val = reflect.ValueOf(obj)
}
return val
}

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util/structfs/structfs_test.go Normal file
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package structfs
import (
"encoding/json"
"io/ioutil"
"net/http"
"reflect"
"testing"
"time"
)
var doOrig = []byte(`{
"droplet_id":2756294,
"hostname":"sample-droplet",
"vendor_data":"#cloud-config\ndisable_root: false\nmanage_etc_hosts: true\n\ncloud_config_modules:\n - ssh\n - set_hostname\n - [ update_etc_hosts, once-per-instance ]\n\ncloud_final_modules:\n - scripts-vendor\n - scripts-per-once\n - scripts-per-boot\n - scripts-per-instance\n - scripts-user\n",
"public_keys":["ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCcbi6cygCUmuNlB0KqzBpHXf7CFYb3VE4pDOf/RLJ8OFDjOM+fjF83a24QktSVIpQnHYpJJT2pQMBxD+ZmnhTbKv+OjwHSHwAfkBullAojgZKzz+oN35P4Ea4J78AvMrHw0zp5MknS+WKEDCA2c6iDRCq6/hZ13Mn64f6c372JK99X29lj/B4VQpKCQyG8PUSTFkb5DXTETGbzuiVft+vM6SF+0XZH9J6dQ7b4yD3sOder+M0Q7I7CJD4VpdVD/JFa2ycOS4A4dZhjKXzabLQXdkWHvYGgNPGA5lI73TcLUAueUYqdq3RrDRfaQ5Z0PEw0mDllCzhk5dQpkmmqNi0F sammy@digitalocean.com"],
"region":"nyc3",
"interfaces":{
"private":[
{
"ipv4":{
"ip_address":"10.132.255.113",
"netmask":"255.255.0.0",
"gateway":"10.132.0.1"
},
"mac":"04:01:2a:0f:2a:02",
"type":"private"
}
],
"public":[
{
"ipv4":{
"ip_address":"104.131.20.105",
"netmask":"255.255.192.0",
"gateway":"104.131.0.1"
},
"ipv6":{
"ip_address":"2604:A880:0800:0010:0000:0000:017D:2001",
"cidr":64,
"gateway":"2604:A880:0800:0010:0000:0000:0000:0001"
},
"mac":"04:01:2a:0f:2a:01",
"type":"public"}
]
},
"floating_ip": {
"ipv4": {
"active": false
}
},
"dns":{
"nameservers":[
"2001:4860:4860::8844",
"2001:4860:4860::8888",
"8.8.8.8"
]
},
"features":{
"dhcp_enabled": true
}
}
`)
func server(t *testing.T) {
stfs := DigitalOceanMetadata{}
err := json.Unmarshal(doOrig, &stfs.Metadata.V1)
if err != nil {
t.Fatal(err)
}
http.Handle("/metadata/v1/", FileServer(&stfs, "json", time.Now()))
http.Handle("/metadata/v1.json", &stfs)
go func() {
t.Fatal(http.ListenAndServe("127.0.0.1:8080", nil))
}()
time.Sleep(2 * time.Second)
}
func get(path string) ([]byte, error) {
res, err := http.Get(path)
if err != nil {
return nil, err
}
defer res.Body.Close()
return ioutil.ReadAll(res.Body)
}
func TestAll(t *testing.T) {
server(t)
var tests = []struct {
in string
out string
}{
{"http://127.0.0.1:8080/metadata/v1/", "droplet_id\nhostname\nvendor_data\npublic_keys\nregion\ninterfaces\nfloating_ip\ndns\nfeatures"},
{"http://127.0.0.1:8080/metadata/v1/droplet_id", "2756294"},
{"http://127.0.0.1:8080/metadata/v1/dns/", "nameservers"},
{"http://127.0.0.1:8080/metadata/v1/dns/nameservers", "2001:4860:4860::8844\n2001:4860:4860::8888\n8.8.8.8"},
{"http://127.0.0.1:8080/metadata/v1/features/dhcp_enabled", "true"},
}
for _, tt := range tests {
buf, err := get(tt.in)
if err != nil {
t.Fatal(err)
}
if string(buf) != tt.out {
t.Errorf("req %s output %s not match requested %s", tt.in, string(buf), tt.out)
}
}
doTest, err := get("http://127.0.0.1:8080/metadata/v1.json")
if err != nil {
t.Fatal(err)
}
oSt := DigitalOceanMetadata{}
err = json.Unmarshal(doOrig, &oSt.Metadata.V1)
if err != nil {
t.Fatal(err)
}
nSt := DigitalOceanMetadata{}
err = json.Unmarshal(doTest, &nSt.Metadata.V1)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(oSt, nSt) {
t.Fatalf("%v not match %v", oSt, nSt)
}
}