fix: update environment variable references for Alibaba Cloud KMS to use ARN format

Signed-off-by: Perrie Qian <perrie-qian@outlook.com>

Author: peiliqiancdt

README.rst

@@ -628,11 +628,11 @@ To encrypt a file, specify the Alibaba Cloud KMS key using its ARN format:
 
     $ sops encrypt --acs-kms acs:kms:cn-shanghai:1234567890:key/key-idxxxx test.yaml > test.enc.yaml
 
-Or using the ``SOPS_ACS_KMS_IDS`` environment variable:
+Or using the ``SOPS_ACS_KMS_ARN`` environment variable:
 
 .. code:: bash
 
-    export SOPS_ACS_KMS_IDS="acs:kms:cn-shanghai:1234567890:key/key-idxxxx"
+    export SOPS_ACS_KMS_ARN="acs:kms:cn-shanghai:1234567890:key/key-idxxxx"
     $ sops encrypt test.yaml > test.enc.yaml
 
 You can also configure Alibaba Cloud KMS keys in the ``.sops.yaml`` config file:
@@ -649,7 +649,7 @@ Adding and removing keys
 When creating new files, ``sops`` uses the PGP, KMS and GCP KMS defined in the
 command line arguments ``--kms``, ``--pgp``, ``--gcp-kms``, ``--acs-kms``, ``--hckms`` or ``--azure-kv``, or from
 the environment variables ``SOPS_KMS_ARN``, ``SOPS_PGP_FP``, ``SOPS_GCP_KMS_IDS``,
-``SOPS_ACS_KMS_IDS``, ``SOPS_HUAWEICLOUD_KMS_IDS``, ``SOPS_AZURE_KEYVAULT_URLS``. That information is stored in the file under the
+``SOPS_ACS_KMS_ARN``, ``SOPS_HUAWEICLOUD_KMS_IDS``, ``SOPS_AZURE_KEYVAULT_URLS``. That information is stored in the file under the
 ``sops`` section, such that decrypting files does not require providing those
 parameters again.
 

cmd/sops/main.go

@@ -112,7 +112,7 @@ func main() {
     https://developers.google.com/identity/protocols/application-default-credentials)
 
    To encrypt or decrypt a document with Alibaba Cloud KMS, specify the
-   Alibaba Cloud KMS key ARN in the --acs-kms flag or in the SOPS_ACS_KMS_IDS
+   Alibaba Cloud KMS key ARN in the --acs-kms flag or in the SOPS_ACS_KMS_ARN
    environment variable.
    (You need to setup Alibaba Cloud credentials via environment variables:
     ALIBABA_CLOUD_ACCESS_KEY_ID, ALIBABA_CLOUD_ACCESS_KEY_SECRET, or
@@ -955,8 +955,8 @@ func main() {
 				},
 				cli.StringFlag{
 					Name:   "acs-kms",
-					Usage:  "comma separated list of Alibaba Cloud KMS key IDs (format: region:key-id)",
-					EnvVar: "SOPS_ACS_KMS_IDS",
+					Usage:  "comma separated list of Alibaba Cloud KMS key ARNs",
+					EnvVar: "SOPS_ACS_KMS_ARN",
 				},
 				cli.StringFlag{
 					Name:   "hckms",
@@ -1319,8 +1319,8 @@ func main() {
 				},
 				cli.StringFlag{
 					Name:   "acs-kms",
-					Usage:  "comma separated list of Alibaba Cloud KMS key IDs (format: region:key-id)",
-					EnvVar: "SOPS_ACS_KMS_IDS",
+					Usage:  "comma separated list of Alibaba Cloud KMS key ARNs",
+					EnvVar: "SOPS_ACS_KMS_ARN",
 				},
 				cli.StringFlag{
 					Name:   "hckms",
@@ -1738,7 +1738,7 @@ func main() {
 		cli.StringFlag{
 			Name:   "acs-kms",
 			Usage:  "comma separated list of Alibaba Cloud KMS key ARNs",
-			EnvVar: "SOPS_ACS_KMS_IDS",
+			EnvVar: "SOPS_ACS_KMS_ARN",
 		},
 		cli.StringFlag{
 			Name:   "hckms",