feat: rotation workflow with just Vault updates

the rotation workflow does currently only update values
in Vault, but at least that works. PostgreSQL is gonna
follow next, no worries.

src/cli.rs

@@ -17,13 +17,11 @@ pub(crate) enum Command {
     /// Initialize a Vault path with the necessary structure for secret management.
     ///
     /// This command prepares the Vault backend for subsequent secret rotation operations.
-    #[command(arg_required_else_help(true))] // Require arguments for this subcommand
     InitVault(InitVaultArgs),
 
     /// Rotate PostgreSQL database secrets.
     ///
     /// This command orchestrates the process of generating new secrets, updating the database, and storing the new secrets in Vault.
-    #[command(arg_required_else_help(true))] // Require arguments for this subcommand
     Rotate(RotateArgs),
 }
 
@@ -43,7 +41,7 @@ pub(crate) struct RotateArgs {
 
     /// Whether the CLI should write a recovery log (contains sensitive information!) or not
     #[clap(short, long, default_value = "20")]
-    pub(crate) password_length: i8,
+    pub(crate) password_length: usize,
 
     /// Whether the CLI should write a recovery log (contains sensitive information!) or not
     #[clap(short, long)]

src/config.rs

@@ -24,7 +24,8 @@ pub(crate) fn read_config(config_path: PathBuf) -> Config {
     debug!("Reading config at: {path_string}");
 
     let mut config_data: String = String::new();
-    let mut config_file: File = File::open(config_path).expect("Failed to read configuration file");
+    let mut config_file: File = File::open(config_path)
+        .expect(format!("Failed to read configuration file: '{path_string}'").as_str());
     config_file
         .read_to_string(&mut config_data)
         .expect("Failed to read configuration file");

src/main.rs

@@ -6,7 +6,7 @@ use config::Config;
 use crate::cli::{CliArgs, Command};
 use crate::config::read_config;
 use crate::vault::Vault;
-use crate::workflow::switch_active_user;
+use crate::workflow::rotate_secrets_using_switch_method;
 
 mod cli;
 mod config;
@@ -21,14 +21,14 @@ fn main() {
 
     match args.command {
         Command::InitVault(int_args) => {
-            let config: Config = read_config(int_args.base.config_path);
+            let config: Config = read_config(int_args.base.config_path.clone());
             let mut vault: Vault = Vault::connect(&config);
             vault.init_secret_path()
         }
         Command::Rotate(rotate_args) => {
-            let config: Config = read_config(rotate_args.base.config_path);
-            let vault: Vault = Vault::connect(&config);
-            switch_active_user(&config, &vault)
+            let config: Config = read_config(rotate_args.base.config_path.clone());
+            let mut vault: Vault = Vault::connect(&config);
+            rotate_secrets_using_switch_method(&rotate_args, &config, &mut vault)
         }
     }
 }

src/password.rs

@@ -1,7 +1,7 @@
 use rand::distributions::Alphanumeric;
 use rand::{thread_rng, Rng};
 
-fn generate_random_password(length: usize) -> String {
+pub(crate) fn generate_random_password(length: usize) -> String {
     let mut rng = thread_rng();
     let password: String = (0..length)
         .map(|_| rng.sample(Alphanumeric) as char)

src/vault.rs

@@ -1,22 +1,25 @@
 use log::info;
+use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use std::env;
 use tokio::runtime::{Builder, Runtime};
+use vaultrs::api::kv2::responses::SecretVersionMetadata;
 use vaultrs::client::{VaultClient, VaultClientSettingsBuilder};
+use vaultrs::error::ClientError;
 use vaultrs::kv2;
 
 use crate::config::{Config, VaultConfig};
 
 const VAULT_TOKEN: &'static str = "VAULT_TOKEN";
 
 #[derive(Debug, Deserialize, Serialize)]
-struct VaultStructure {
-    postgresql_active_user: String,
-    postgresql_active_user_password: String,
-    postgresql_user_1: String,
-    postgresql_user_1_password: String,
-    postgresql_user_2: String,
-    postgresql_user_2_password: String,
+pub(crate) struct VaultStructure {
+    pub(crate) postgresql_active_user: String,
+    pub(crate) postgresql_active_user_password: String,
+    pub(crate) postgresql_user_1: String,
+    pub(crate) postgresql_user_1_password: String,
+    pub(crate) postgresql_user_2: String,
+    pub(crate) postgresql_user_2_password: String,
 }
 
 pub(crate) struct Vault {
@@ -51,20 +54,34 @@ impl Vault {
             postgresql_user_2_password: "TBD".to_string(),
         };
 
-        self.rt
-            .block_on(kv2::set(
-                &self.vault_client,
-                "secret",
-                &*self.vault_config.path,
-                &vault_structure,
-            ))
+        self.write_secret(&vault_structure)
             .expect("Failed to create initial Vault structure");
 
         println!(
             "Successfully initialized Vault path '{}'",
             self.vault_config.path
         )
     }
+
+    pub(crate) fn read_secret<D: DeserializeOwned>(&mut self) -> Result<D, ClientError> {
+        self.rt.block_on(kv2::read(
+            &self.vault_client,
+            "secret",
+            &*self.vault_config.path,
+        ))
+    }
+
+    pub(crate) fn write_secret(
+        &mut self,
+        vault_structure: &VaultStructure,
+    ) -> Result<SecretVersionMetadata, ClientError> {
+        self.rt.block_on(kv2::set(
+            &self.vault_client,
+            "secret",
+            &*self.vault_config.path,
+            &vault_structure,
+        ))
+    }
 }
 
 fn get_vault_client(config: &Config) -> VaultClient {

src/workflow.rs

@@ -1,4 +1,61 @@
+use crate::cli::RotateArgs;
 use crate::config::Config;
-use crate::vault::Vault;
+use crate::password::generate_random_password;
+use crate::vault::{Vault, VaultStructure};
+use log::debug;
+use vaultrs::auth::userpass::user::update_password;
 
-pub(crate) fn switch_active_user(config: &Config, vault: &Vault) {}
+pub(crate) fn rotate_secrets_using_switch_method(
+    rotate_args: &RotateArgs,
+    config: &Config,
+    vault: &mut Vault,
+) {
+    debug!("Starting 'switch' workflow");
+
+    let vault_path = config.vault.clone().path;
+    let mut secret: VaultStructure = vault
+        .read_secret()
+        .expect(format!("Failed to read path '{vault_path}' - did you init Vault?").as_str());
+
+    if secret.postgresql_active_user != secret.postgresql_user_1
+        && secret.postgresql_active_user != secret.postgresql_user_2
+    {
+        panic!("Failed to detect active user - did neither match user 1 nor 2")
+    }
+
+    let new_password: String = generate_random_password(rotate_args.password_length);
+    update_passive_user_password(&mut secret, new_password);
+    switch_active_user(&mut secret);
+
+    vault
+        .write_secret(&secret)
+        .expect("Failed to kick-off rotation workflow by switching active user");
+
+    // TODO: Trigger ArgoCD Sync
+
+    let new_password: String = generate_random_password(rotate_args.password_length);
+    update_passive_user_password(&mut secret, new_password);
+    vault
+        .write_secret(&secret)
+        .expect("Failed to update PASSIVE user password after sync");
+
+    println!("Successfully rotated all secrets")
+}
+
+fn switch_active_user(secret: &mut VaultStructure) {
+    if secret.postgresql_active_user == secret.postgresql_user_1 {
+        secret.postgresql_active_user = secret.postgresql_user_2.clone();
+        secret.postgresql_active_user_password = secret.postgresql_user_2_password.clone()
+    } else {
+        secret.postgresql_active_user = secret.postgresql_user_1.clone();
+        secret.postgresql_active_user_password = secret.postgresql_user_1_password.clone()
+    }
+}
+
+fn update_passive_user_password(secret: &mut VaultStructure, new_password: String) {
+    if secret.postgresql_active_user == secret.postgresql_user_1 {
+        secret.postgresql_user_2_password = new_password.clone();
+    } else {
+        secret.postgresql_user_1_password = new_password.clone();
+    }
+}