Add DumpConfigs

validator_manager/src/lib.rs

@@ -1,12 +1,36 @@
 use clap::App;
 use clap::ArgMatches;
 use environment::Environment;
+use serde::Serialize;
+use std::path::PathBuf;
 use types::EthSpec;
+use validators::create_validators::write_to_json_file;
 
 mod validators;
 
 pub const CMD: &str = "validator_manager";
 
+/// This flag is on the top-level `lighthouse` binary.
+const DUMP_CONFIGS_FLAG: &str = "dump-configs";
+
+/// Used only in testing, this allows a command to dump its configuration to a file and then exit
+/// successfully. This allows for testing how the CLI arguments translate to some configuration.
+pub enum DumpConfigs {
+    Disabled,
+    Enabled(PathBuf),
+}
+
+impl DumpConfigs {
+    /// Returns `Ok(true)` if the configuration was successfully written to a file and the
+    /// application should exit successfully without doing anything else.
+    pub fn should_exit_early<T: Serialize>(&self, config: &T) -> Result<bool, String> {
+        match self {
+            DumpConfigs::Disabled => Ok(false),
+            DumpConfigs::Enabled(dump_path) => write_to_json_file(dump_path, config).map(|()| true),
+        }
+    }
+}
+
 pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
     App::new(CMD)
         .visible_aliases(&["vm", CMD])
@@ -21,6 +45,9 @@ pub fn run<'a, T: EthSpec>(
 ) -> Result<(), String> {
     let context = env.core_context();
     let spec = context.eth2_config.spec.clone();
+    let dump_configs = clap_utils::parse_optional(matches, DUMP_CONFIGS_FLAG)?
+        .map(DumpConfigs::Enabled)
+        .unwrap_or_else(|| DumpConfigs::Disabled);
 
     context
         .executor
@@ -31,7 +58,7 @@ pub fn run<'a, T: EthSpec>(
             async {
                 match matches.subcommand() {
                     (validators::CMD, Some(matches)) => {
-                        validators::cli_run::<T>(matches, &spec).await
+                        validators::cli_run::<T>(matches, &spec, dump_configs).await
                     }
                     (unknown, _) => Err(format!(
                         "{} is not a valid {} command. See --help.",