'policies patch', a new command for partial policy definition updates

Author: michaelklishin

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ### Enhancements
 
+ * `policies set` and `policies update` are two new aliases for `policies declare`. The former follows the naming
+   used by `rabbitmqctl` and the latter reflects the fact that the command can be used to update an existing policy,
+   in particular, to override its definition
+ * `policies patch` is a new command that updates a policy definition by merging the provided definition with the existing one
  * `parameters list_all` is a new command that lists all runtime parameters across all virtual hosts
  * `parameters list_in` is a new command that lists runtime parameters of a given component (type)
    in a specific virtual host

src/cli.rs

@@ -1585,8 +1585,9 @@ fn global_parameters_subcommands(pre_flight_settings: PreFlightSettings) -> [Com
         .map(|cmd| cmd.infer_long_args(pre_flight_settings.infer_long_options))
 }
 
-fn policies_subcommands(pre_flight_settings: PreFlightSettings) -> [Command; 9] {
+fn policies_subcommands(pre_flight_settings: PreFlightSettings) -> [Command; 10] {
     let declare_cmd = Command::new("declare")
+        .visible_aliases(vec!["update", "set"])
         .about("Creates or updates a policy")
         .after_help(color_print::cformat!("<bold>Doc guide:</bold>: {}", POLICY_GUIDE_URL))
         .arg(
@@ -1684,6 +1685,20 @@ fn policies_subcommands(pre_flight_settings: PreFlightSettings) -> [Command; 9]
                 .help("target type, one of 'queues', 'streams', 'exchanges'"),
         );
 
+    let patch_cmd = Command::new("patch")
+        .about("Merges a set of keys into existing policy definitions")
+        .arg(
+            Arg::new("name")
+                .long("name")
+                .help("policy name")
+                .required(true),
+        )
+        .arg(
+            Arg::new("definition")
+                .long("definition")
+                .help("policy definition changes to merge into the existing ones"),
+        );
+
     let update_cmd = Command::new("update_definition")
         .about("Updates a policy definition key")
         .arg(
@@ -1728,6 +1743,7 @@ fn policies_subcommands(pre_flight_settings: PreFlightSettings) -> [Command; 9]
         list_cmd,
         list_in_cmd,
         list_matching_cmd,
+        patch_cmd,
         update_cmd,
         update_all_in_cmd,
     ]

src/commands.rs

@@ -1052,6 +1052,31 @@ pub fn update_policy_definition(
     update_policy_definition_with(&client, vhost, &name, &key, &parsed_value)
 }
 
+pub fn patch_policy_definition(
+    client: APIClient,
+    vhost: &str,
+    command_args: &ArgMatches,
+) -> ClientResult<()> {
+    let name = command_args.get_one::<String>("name").cloned().unwrap();
+    let value = command_args
+        .get_one::<String>("definition")
+        .cloned()
+        .unwrap();
+    let parsed_value = serde_json::from_str::<serde_json::Value>(&value).unwrap_or_else(|err| {
+        eprintln!("`{}` is not a valid JSON value: {}", value, err);
+        process::exit(1);
+    });
+
+    let mut pol = client.get_policy(vhost, &name)?;
+    let patch = parsed_value.as_object().unwrap();
+    for (k, v) in patch.iter() {
+        pol.insert_definition_key(k.clone(), v.clone());
+    }
+
+    let params = PolicyParams::from(&pol);
+    client.declare_policy(&params)
+}
+
 pub fn update_all_policy_definitions_in(
     client: APIClient,
     vhost: &str,

src/main.rs

@@ -683,6 +683,10 @@ fn dispatch_common_subcommand(
             let result = commands::list_matching_policies_in(client, &vhost, &name, typ);
             res_handler.tabular_result(result)
         }
+        ("policies", "patch") => {
+            let result = commands::patch_policy_definition(client, &vhost, second_level_args);
+            res_handler.no_output_on_success(result);
+        }
         ("policies", "update_definition") => {
             let result = commands::update_policy_definition(client, &vhost, second_level_args);
             res_handler.no_output_on_success(result);

tests/policies_tests.rs

@@ -513,3 +513,47 @@ fn test_policies_bulk_policy_key_manipulation() -> Result<(), Box<dyn std::error
 
     Ok(())
 }
+
+#[test]
+fn test_policies_patch_definition() -> Result<(), Box<dyn std::error::Error>> {
+    let policy_name = "test_policies_patch_definition";
+
+    run_succeeds([
+        "policies",
+        "declare",
+        "--name",
+        policy_name,
+        "--pattern",
+        "foo-.*",
+        "--apply-to",
+        "queues",
+        "--priority",
+        "123",
+        "--definition",
+        "{\"max-length\": 20, \"max-length-bytes\": 99999999}",
+    ]);
+    run_succeeds(["policies", "list"])
+        .stdout(predicate::str::contains(policy_name).and(predicate::str::contains("20")));
+
+    run_succeeds([
+        "policies",
+        "patch",
+        "--name",
+        policy_name,
+        "--definition",
+        "{\"max-length\": 29, \"max-length-bytes\": 8888888888}",
+    ]);
+
+    run_succeeds(["policies", "list"]).stdout(
+        predicate::str::contains(policy_name)
+            .and(predicate::str::contains("8888888888"))
+            .and(predicate::str::contains("29")),
+    );
+
+    run_succeeds(["policies", "list"]).stdout(predicate::str::contains("99999999").not());
+
+    run_succeeds(["policies", "delete", "--name", policy_name]);
+    run_succeeds(["policies", "list"]).stdout(predicate::str::contains(policy_name).not());
+
+    Ok(())
+}