callbacks service draft

ci/dev/vault-agent/callbacks.hcl

@@ -0,0 +1,20 @@
+vault {
+  address = "http://dev-vault:8200"
+}
+
+auto_auth {
+  method "approle" {
+    mount_path = "auth/approle"
+    config = {
+      role_id_file_path    = "/run/vault/role_id"
+      secret_id_file_path  = "/run/vault/secret_id"
+    }
+  }
+
+  sink "file" {
+    config = {
+      path = "/run/vault/token"
+      mode = 0600
+    }
+  }
+}