From f49f55f4a51e0e5eb84212d670a3ac373ff78acb Mon Sep 17 00:00:00 2001
From: Mal Graty <mal.graty@googlemail.com>
Date: Tue, 20 Feb 2018 14:55:05 +0000
Subject: [PATCH] Pull AWS creds from container role
Extend the AWS DNS API driver to support ECS container metadata by using
the special environment variable ECS sets in containers.
---
dnsapi/dns_aws.sh | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/dnsapi/dns_aws.sh b/dnsapi/dns_aws.sh
index 9c9e931..8ce7c34 100755
--- a/dnsapi/dns_aws.sh
+++ b/dnsapi/dns_aws.sh
@@ -23,7 +23,7 @@ dns_aws_add() {
AWS_SECRET_ACCESS_KEY="${AWS_SECRET_ACCESS_KEY:-$(_readaccountconf_mutable AWS_SECRET_ACCESS_KEY)}"
if [ -z "$AWS_ACCESS_KEY_ID" ] || [ -z "$AWS_SECRET_ACCESS_KEY" ]; then
- _use_instance_role
+ _use_container_role || _use_instance_role
fi
if [ -z "$AWS_ACCESS_KEY_ID" ] || [ -z "$AWS_SECRET_ACCESS_KEY" ]; then
@@ -87,7 +87,7 @@ dns_aws_rm() {
AWS_SECRET_ACCESS_KEY="${AWS_SECRET_ACCESS_KEY:-$(_readaccountconf_mutable AWS_SECRET_ACCESS_KEY)}"
if [ -z "$AWS_ACCESS_KEY_ID" ] || [ -z "$AWS_SECRET_ACCESS_KEY" ]; then
- _use_instance_role
+ _use_container_role || _use_instance_role
fi
_debug "First detect the root zone"
@@ -174,17 +174,30 @@ _get_root() {
return 1
}
+_use_container_role() {
+ # automatically set if running inside ECS
+ if [ -z "$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI" ]; then
+ _debug "No ECS environment variable detected"
+ return 1
+ fi
+ _use_metadata "169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI"
+}
+
_use_instance_role() {
_url="http://169.254.169.254/latest/meta-data/iam/security-credentials/"
_debug "_url" "$_url"
if ! _get "$_url" true 1 | _head_n 1 | grep -Fq 200; then
- _err "Unable to fetch IAM role from AWS instance metadata."
- return
+ _debug "Unable to fetch IAM role from instance metadata"
+ return 1
fi
_aws_role=$(_get "$_url" "" 1)
_debug "_aws_role" "$_aws_role"
+ _use_metadata "$_url$_aws_role"
+}
+
+_use_metadata() {
_aws_creds="$(
- _get "$_url$_aws_role" "" 1 \
+ _get "$1" "" 1 \
| _normalizeJson \
| tr '{,}' '\n' \
| while read -r _line; do
@@ -201,6 +214,11 @@ _use_instance_role() {
| paste -sd' ' -
)"
_secure_debug "_aws_creds" "$_aws_creds"
+
+ if [ -z "$_aws_creds" ]; then
+ return 1
+ fi
+
eval "$_aws_creds"
_using_role=true
}