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datasource.go
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datasource.go
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package data
import (
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"mime"
"net/http"
"net/url"
"os"
"path"
"path/filepath"
"strings"
"time"
"github.com/aws/aws-sdk-go/service/ssm"
"github.com/blang/vfs"
"github.com/hairyhenderson/gomplate/libkv"
"github.com/hairyhenderson/gomplate/vault"
)
// logFatal is defined so log.Fatal calls can be overridden for testing
var logFatalf = log.Fatalf
var json_mimetype = "application/json"
// stdin - for overriding in tests
var stdin io.Reader
func regExtension(ext, typ string) {
err := mime.AddExtensionType(ext, typ)
if err != nil {
log.Fatal(err)
}
}
func init() {
// Add some types we want to be able to handle which can be missing by default
regExtension(".json", "application/json")
regExtension(".yml", "application/yaml")
regExtension(".yaml", "application/yaml")
regExtension(".csv", "text/csv")
regExtension(".toml", "application/toml")
sourceReaders = make(map[string]func(*Source, ...string) ([]byte, error))
// Register our source-reader functions
addSourceReader("http", readHTTP)
addSourceReader("https", readHTTP)
addSourceReader("file", readFile)
addSourceReader("stdin", readStdin)
addSourceReader("vault", readVault)
addSourceReader("vault+http", readVault)
addSourceReader("vault+https", readVault)
addSourceReader("consul", readConsul)
addSourceReader("consul+http", readConsul)
addSourceReader("consul+https", readConsul)
addSourceReader("boltdb", readBoltDB)
addSourceReader("aws+smp", readAWSSMP)
}
var sourceReaders map[string]func(*Source, ...string) ([]byte, error)
// addSourceReader -
func addSourceReader(scheme string, readFunc func(*Source, ...string) ([]byte, error)) {
sourceReaders[scheme] = readFunc
}
// Data -
type Data struct {
Sources map[string]*Source
cache map[string][]byte
}
// Cleanup - clean up datasources before shutting the process down - things
// like Logging out happen here
func (d *Data) Cleanup() {
for _, s := range d.Sources {
s.cleanup()
}
}
// NewData - constructor for Data
func NewData(datasourceArgs []string, headerArgs []string) *Data {
sources := make(map[string]*Source)
headers := parseHeaderArgs(headerArgs)
for _, v := range datasourceArgs {
s, err := ParseSource(v)
if err != nil {
log.Fatalf("error parsing datasource %v", err)
return nil
}
s.Header = headers[s.Alias]
sources[s.Alias] = s
}
return &Data{
Sources: sources,
}
}
// - A subset of SSM API for use in unit testing
type AWSSMPGetter interface {
GetParameter(*ssm.GetParameterInput) (*ssm.GetParameterOutput, error)
}
// Source - a data source
type Source struct {
Alias string
URL *url.URL
Ext string
Type string
Params map[string]string
FS vfs.Filesystem // used for file: URLs, nil otherwise
HC *http.Client // used for http[s]: URLs, nil otherwise
VC *vault.Vault // used for vault: URLs, nil otherwise
KV *libkv.LibKV // used for consul:, etcd:, zookeeper: & boltdb: URLs, nil otherwise
ASMPG AWSSMPGetter // used for aws+smp:, nil otherwise
Header http.Header // used for http[s]: URLs, nil otherwise
}
func (s *Source) cleanup() {
if s.VC != nil {
s.VC.Logout()
}
if s.KV != nil {
s.KV.Logout()
}
}
// NewSource - builds a &Source
func NewSource(alias string, URL *url.URL) *Source {
ext := filepath.Ext(URL.Path)
s := &Source{
Alias: alias,
URL: URL,
Ext: ext,
}
mediatype := s.URL.Query().Get("type")
if mediatype == "" {
mediatype = mime.TypeByExtension(ext)
}
if mediatype != "" {
t, params, err := mime.ParseMediaType(mediatype)
if err != nil {
log.Fatal(err)
}
s.Type = t
s.Params = params
}
if s.Type == "" {
s.Type = plaintext
}
return s
}
// String is the method to format the flag's value, part of the flag.Value interface.
// The String method's output will be used in diagnostics.
func (s *Source) String() string {
return fmt.Sprintf("%s=%s (%s)", s.Alias, s.URL.String(), s.Type)
}
// ParseSource -
func ParseSource(value string) (*Source, error) {
var (
alias string
srcURL *url.URL
)
parts := strings.SplitN(value, "=", 2)
if len(parts) == 1 {
f := parts[0]
alias = strings.SplitN(value, ".", 2)[0]
if path.Base(f) != f {
err := fmt.Errorf("Invalid datasource (%s). Must provide an alias with files not in working directory", value)
return nil, err
}
srcURL = absURL(f)
} else if len(parts) == 2 {
alias = parts[0]
if parts[1] == "-" {
parts[1] = "stdin://"
}
var err error
srcURL, err = url.Parse(parts[1])
if err != nil {
return nil, err
}
if !srcURL.IsAbs() {
srcURL = absURL(parts[1])
}
}
s := NewSource(alias, srcURL)
return s, nil
}
func absURL(value string) *url.URL {
cwd, err := os.Getwd()
if err != nil {
log.Fatalf("Can't get working directory: %s", err)
}
urlCwd := strings.Replace(cwd, string(os.PathSeparator), "/", -1)
baseURL := &url.URL{
Scheme: "file",
Path: urlCwd + "/",
}
relURL := &url.URL{
Path: value,
}
return baseURL.ResolveReference(relURL)
}
// DatasourceExists -
func (d *Data) DatasourceExists(alias string) bool {
_, ok := d.Sources[alias]
return ok
}
const plaintext = "text/plain"
// Datasource -
func (d *Data) Datasource(alias string, args ...string) interface{} {
source, ok := d.Sources[alias]
if !ok {
log.Fatalf("Undefined datasource '%s'", alias)
}
b, err := d.ReadSource(source, args...)
if err != nil {
logFatalf("Couldn't read datasource '%s': %s", alias, err)
}
if b == nil || len(b) == 0 {
logFatalf("No value found for %s from datasource '%s'", args, alias)
}
s := string(b)
if source.Type == json_mimetype {
return JSON(s)
}
if source.Type == "application/yaml" {
return YAML(s)
}
if source.Type == "text/csv" {
return CSV(s)
}
if source.Type == "application/toml" {
return TOML(s)
}
if source.Type == plaintext {
return s
}
log.Fatalf("Datasources of type %s not yet supported", source.Type)
return nil
}
// Include -
func (d *Data) Include(alias string, args ...string) string {
source, ok := d.Sources[alias]
if !ok {
log.Fatalf("Undefined datasource '%s'", alias)
}
b, err := d.ReadSource(source, args...)
if err != nil {
log.Fatalf("Couldn't read datasource '%s': %s", alias, err)
}
return string(b)
}
// ReadSource -
func (d *Data) ReadSource(source *Source, args ...string) ([]byte, error) {
if d.cache == nil {
d.cache = make(map[string][]byte)
}
cacheKey := source.Alias
for _, v := range args {
cacheKey += v
}
cached, ok := d.cache[cacheKey]
if ok {
return cached, nil
}
if r, ok := sourceReaders[source.URL.Scheme]; ok {
data, err := r(source, args...)
if err != nil {
return nil, err
}
d.cache[cacheKey] = data
return data, nil
}
log.Fatalf("Datasources with scheme %s not yet supported", source.URL.Scheme)
return nil, nil
}
func readFile(source *Source, args ...string) ([]byte, error) {
if source.FS == nil {
source.FS = vfs.OS()
}
p := filepath.FromSlash(source.URL.Path)
// make sure we can access the file
_, err := source.FS.Stat(p)
if err != nil {
log.Fatalf("Can't stat %s: %#v", p, err)
return nil, err
}
f, err := source.FS.OpenFile(p, os.O_RDONLY, 0)
if err != nil {
log.Fatalf("Can't open %s: %#v", p, err)
return nil, err
}
b, err := ioutil.ReadAll(f)
if err != nil {
log.Fatalf("Can't read %s: %#v", p, err)
return nil, err
}
return b, nil
}
func readStdin(source *Source, args ...string) ([]byte, error) {
if stdin == nil {
stdin = os.Stdin
}
b, err := ioutil.ReadAll(stdin)
if err != nil {
log.Printf("Can't read %v: %#v", stdin, err)
return nil, err
}
return b, nil
}
func readHTTP(source *Source, args ...string) ([]byte, error) {
if source.HC == nil {
source.HC = &http.Client{Timeout: time.Second * 5}
}
req, err := http.NewRequest("GET", source.URL.String(), nil)
if err != nil {
return nil, err
}
req.Header = source.Header
res, err := source.HC.Do(req)
if err != nil {
return nil, err
}
body, err := ioutil.ReadAll(res.Body)
if err != nil {
return nil, err
}
err = res.Body.Close()
if err != nil {
return nil, err
}
if res.StatusCode != 200 {
err := fmt.Errorf("Unexpected HTTP status %d on GET from %s: %s", res.StatusCode, source.URL, string(body))
return nil, err
}
ctypeHdr := res.Header.Get("Content-Type")
if ctypeHdr != "" {
mediatype, params, e := mime.ParseMediaType(ctypeHdr)
if e != nil {
return nil, e
}
source.Type = mediatype
source.Params = params
}
return body, nil
}
func readVault(source *Source, args ...string) ([]byte, error) {
if source.VC == nil {
source.VC = vault.New(source.URL)
source.VC.Login()
}
params := make(map[string]interface{})
p := source.URL.Path
for key, val := range source.URL.Query() {
params[key] = strings.Join(val, " ")
}
if len(args) == 1 {
parsed, err := url.Parse(args[0])
if err != nil {
return nil, err
}
if parsed.Path != "" {
p = p + "/" + parsed.Path
}
for key, val := range parsed.Query() {
params[key] = strings.Join(val, " ")
}
}
var data []byte
var err error
if len(params) > 0 {
data, err = source.VC.Write(p, params)
} else {
data, err = source.VC.Read(p)
}
if err != nil {
return nil, err
}
source.Type = "application/json"
return data, nil
}
func readConsul(source *Source, args ...string) ([]byte, error) {
if source.KV == nil {
source.KV = libkv.NewConsul(source.URL)
err := source.KV.Login()
if err != nil {
return nil, err
}
}
p := source.URL.Path
if len(args) == 1 {
p = p + "/" + args[0]
}
data, err := source.KV.Read(p)
if err != nil {
return nil, err
}
return data, nil
}
func readBoltDB(source *Source, args ...string) ([]byte, error) {
if source.KV == nil {
source.KV = libkv.NewBoltDB(source.URL)
}
if len(args) != 1 {
return nil, errors.New("missing key")
}
p := args[0]
data, err := source.KV.Read(p)
if err != nil {
return nil, err
}
return data, nil
}
func parseHeaderArgs(headerArgs []string) map[string]http.Header {
headers := make(map[string]http.Header)
for _, v := range headerArgs {
ds, name, value := splitHeaderArg(v)
if _, ok := headers[ds]; !ok {
headers[ds] = make(http.Header)
}
headers[ds][name] = append(headers[ds][name], strings.TrimSpace(value))
}
return headers
}
func splitHeaderArg(arg string) (datasourceAlias, name, value string) {
parts := strings.SplitN(arg, "=", 2)
if len(parts) != 2 {
logFatalf("Invalid datasource-header option '%s'", arg)
return "", "", ""
}
datasourceAlias = parts[0]
name, value = splitHeader(parts[1])
return datasourceAlias, name, value
}
func splitHeader(header string) (name, value string) {
parts := strings.SplitN(header, ":", 2)
if len(parts) != 2 {
logFatalf("Invalid HTTP Header format '%s'", header)
return "", ""
}
name = http.CanonicalHeaderKey(parts[0])
value = parts[1]
return name, value
}