forked from Lavode/get-ssm-params
/
main.go
193 lines (169 loc) · 5.99 KB
/
main.go
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package main
import (
"context"
"errors"
"flag"
"fmt"
"io/ioutil"
"os"
"regexp"
"strings"
"syscall"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/credentials/stscreds"
"github.com/aws/aws-sdk-go/aws/request"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/s3"
"github.com/aws/aws-sdk-go/service/ssm"
)
// AppVersion is set at compile time
var AppVersion = "0.0.0-dev"
func main() {
var defaultRegion string
if os.Getenv("SSM_AWS_REGION") == "" {
defaultRegion = "eu-central-1"
} else {
defaultRegion = os.Getenv("SSM_AWS_REGION")
}
var environment = flag.String("env", os.Getenv("SSM_ENV"), "[$SSM_ENV] environment name to use (PROD, STAG, ...)")
var service = flag.String("service", os.Getenv("SSM_SERVICE"), "[$SSM_SERVICE] service name to use (YVES, ZED, ...)")
var envparams = flag.String("params", os.Getenv("SSM_PARAMS"), "[$SSM_PARAMS] parameters to fetch (prefixes env+service)")
var extraparams = flag.String("extraparams", os.Getenv("SSM_EXTRA_PARAMS"), "[$SSM_EXTRA_PARAMS] parameters to fetch (explicit)")
var awsregion = flag.String("awsregion", defaultRegion, "[$SSM_AWS_REGION] AWS region")
var roleARN = flag.String("rolearn", os.Getenv("SSM_ROLEARN"), "[$SSM_ROLE_ARN] use given IAM role (ARN)")
var printVersion = flag.Bool("version", false, "Print version of get-ssm-params")
var s3Get = flag.Bool("s3-get", false, "fetch file from S3, args: [bucket] [key] [localFile]")
flag.Parse()
if *printVersion {
fmt.Println(AppVersion)
os.Exit(0)
}
// just exec() if SSM_PARAMS not set -- used to run/test containers outside of ECS
if *envparams == "" && len(flag.Args()) > 0 {
fmt.Println("Notice: No SSM_PARAMS provided to get-ssm-params. Passing through to exec().")
env := os.Environ()
execErr := syscall.Exec(flag.Args()[0], flag.Args(), env)
errorExit("Failed to execute", execErr)
}
os.Setenv("AWS_REGION", *awsregion)
sess := session.Must(session.NewSession())
// retrieve single file from S3 if '-s3-get' was given
if *s3Get {
if len(flag.Args()) == 3 {
s3GetFile(sess, *roleARN, flag.Args()[0], flag.Args()[1], flag.Args()[2])
os.Exit(0)
}
fmt.Println("Bad usage, try: get-ssm-params --s3-get bucket key localName")
os.Exit(1)
}
// by default, get SSM parameters
ssmGet(sess, *roleARN, environment, service, envparams, extraparams)
}
func s3GetFile(sess *session.Session, arn string, bucket, key, localPath string) {
sessConfig := &aws.Config{}
if arn != "" {
creds := stscreds.NewCredentials(sess, arn)
sessConfig = &aws.Config{Credentials: creds}
}
svc := s3.New(sess, sessConfig)
var timeout = time.Second * 30
ctx := context.Background()
var cancelFn func()
ctx, cancelFn = context.WithTimeout(ctx, timeout)
defer cancelFn()
var input = &s3.GetObjectInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
}
o, err := svc.GetObjectWithContext(ctx, input)
if err != nil {
if aerr, ok := err.(awserr.Error); ok && aerr.Code() == request.CanceledErrorCode {
errorExit("Download canceled due to timeout", err)
} else {
errorExit("Failed to download object", err)
}
}
// slurp S3 file into memory, assuming small files...
body, err := ioutil.ReadAll(o.Body)
errorExit("reading body", err)
// write file from memory to disk
err = ioutil.WriteFile(localPath, body, 0644)
errorExit(fmt.Sprintf("writing %s", localPath), err)
fmt.Printf("SUCCESS Fetching 's3://%s/%s' -> '%s' (%d bytes)\n", bucket, key, localPath, *o.ContentLength)
}
func ssmGet(sess *session.Session, arn string, environment, service, envparams, extraparams *string) {
sessConfig := &aws.Config{}
if arn != "" {
creds := stscreds.NewCredentials(sess, arn)
sessConfig = &aws.Config{Credentials: creds}
}
svc := ssm.New(sess, sessConfig)
params := &ssm.GetParametersInput{
Names: cliParams(*environment, *service, *envparams, *extraparams),
WithDecryption: aws.Bool(true),
}
resp, err := svc.GetParameters(params)
errorExit("GetParameters", err)
// exit(1) if user requested parameters that do not exist (fail early...)
if len(resp.InvalidParameters) > 0 {
fmt.Println("ERROR: Invalid/Unavailable parameter(s):")
for _, p := range resp.InvalidParameters {
fmt.Printf(" - %s\n", *p)
}
os.Exit(1)
}
if len(flag.Args()) == 0 {
// print all the valid parameters we have, ready-to-source
for _, p := range resp.Parameters {
fmt.Printf(`%s="%s"`+"\n", stripEnvAndService(*p.Name, *environment, *service), *p.Value)
}
} else {
// execute given entrypoint with parameters added to environment
for _, p := range resp.Parameters {
os.Setenv(stripEnvAndService(*p.Name, *environment, *service), *p.Value)
}
env := os.Environ()
execErr := syscall.Exec(flag.Args()[0], flag.Args(), env)
errorExit("Failed to execute", execErr)
}
}
// cliParams builds and returns array of parameters to retrieve, based on command line args
func cliParams(env string, service string, params string, extraparams string) []*string {
p := []*string{}
// handle env/svc specific -params
if params != "" {
if env == "" || service == "" {
errorExit("bad arguments", errors.New("-env and -service must be given for -params to work"))
}
pp := strings.Split(params, ",")
for _, arg := range pp {
p = append(p, aws.String(fmt.Sprintf("%s_%s_%s", env, service, arg)))
}
}
// handle -extraparams; again, comma-separated
if extraparams != "" {
pp := strings.Split(extraparams, ",")
for _, arg := range pp {
p = append(p, aws.String(arg))
}
}
if len(p) == 0 {
errorExit("bad usage", errors.New("try -h for help"))
}
return p
}
// strnilipEnvAndService strips environment name and service name from <in>,
// eg. PROD_FOO_DB_USER -> DB_USER
func stripEnvAndService(in string, env string, service string) string {
reg, _ := regexp.Compile("^" + env + "_" + service + "_")
return reg.ReplaceAllString(in, "")
}
// errorExit bails out on error
func errorExit(msg string, e error) {
if e != nil {
fmt.Fprintf(os.Stderr, "ERROR: %s, %v\n", msg, e)
os.Exit(1)
}
}