Support custom paths for secret files in docker-entrypoint.sh (#10344)

dockerscripts/docker-entrypoint.sh

@@ -22,10 +22,18 @@ if [ "${1}" != "minio" ]; then
     fi
 fi
 
-## Look for docker secrets in default documented location.
+## Look for docker secrets at given absolute path or in default documented location.
 docker_secrets_env() {
+    if [ -f "$MINIO_ACCESS_KEY_FILE" ]; then
+        ACCESS_KEY_FILE="$MINIO_ACCESS_KEY_FILE"
+    else
         ACCESS_KEY_FILE="/run/secrets/$MINIO_ACCESS_KEY_FILE"
+    fi
+    if [ -f "$MINIO_SECRET_KEY_FILE" ]; then
+        SECRET_KEY_FILE="$MINIO_SECRET_KEY_FILE"
+    else
         SECRET_KEY_FILE="/run/secrets/$MINIO_SECRET_KEY_FILE"
+    fi
 
     if [ -f "$ACCESS_KEY_FILE" ] && [ -f "$SECRET_KEY_FILE" ]; then
         if [ -f "$ACCESS_KEY_FILE" ]; then
@@ -41,12 +49,15 @@ docker_secrets_env() {
 
 ## Set KMS_MASTER_KEY from docker secrets if provided
 docker_kms_encryption_env() {
+    if [ -f "$MINIO_KMS_MASTER_KEY_FILE" ]; then
+        KMS_MASTER_KEY_FILE="$MINIO_KMS_MASTER_KEY_FILE"
+    else
         KMS_MASTER_KEY_FILE="/run/secrets/$MINIO_KMS_MASTER_KEY_FILE"
+    fi
 
     if [ -f "$KMS_MASTER_KEY_FILE" ]; then
         MINIO_KMS_MASTER_KEY="$(cat "$KMS_MASTER_KEY_FILE")"
         export MINIO_KMS_MASTER_KEY
-
     fi
 }
 
@@ -58,7 +69,6 @@ docker_sse_encryption_env() {
     if [ -f "$SSE_MASTER_KEY_FILE" ]; then
         MINIO_SSE_MASTER_KEY="$(cat "$SSE_MASTER_KEY_FILE")"
         export MINIO_SSE_MASTER_KEY
-
     fi
 }
 

docs/docker/README.md

@@ -121,6 +121,11 @@ docker service create --name="minio-service" \
   --env="MINIO_SECRET_KEY_FILE=my_secret_key" \
   minio/minio server /data
 ```
+`MINIO_ACCESS_KEY_FILE` and `MINIO_SECRET_KEY_FILE` also support custom absolute paths, in case Docker secrets are mounted to custom locations or other tools are used to mount secrets into the container. For example, HashiCorp Vault injects secrets to `/vault/secrets`. With the custom names above, set the environment variables to
+```
+MINIO_ACCESS_KEY_FILE=/vault/secrets/my_access_key
+MINIO_SECRET_KEY_FILE=/vault/secrets/my_secret_key
+```
 
 ### Retrieving Container ID
 To use Docker commands on a specific container, you need to know the `Container ID` for that container. To get the `Container ID`, run