Use cw-controllers per @maxrobot's suggest

contracts/liquidator/src/contract.rs

@@ -1,5 +1,5 @@
 use cosmwasm_std::{
-    entry_point, to_binary, Binary, Deps, DepsMut, Env, MessageInfo, Response, StdResult,
+    entry_point, to_binary, Binary, Deps, DepsMut, Env, MessageInfo, Response, StdError, StdResult,
 };
 use cw2::set_contract_version;
 
@@ -34,7 +34,7 @@ pub fn instantiate(
 
     let owner_address = deps.api.addr_validate(&msg.owner)?;
 
-    OWNER.save(deps.storage, &owner_address)?;
+    OWNER.set(deps, Some(owner_address))?;
 
     Ok(Response::new().add_attribute("method", "instantiate").add_attribute("owner", info.sender))
 }
@@ -68,7 +68,9 @@ pub fn execute(
 #[cfg_attr(not(feature = "library"), entry_point)]
 pub fn query(deps: Deps, _env: Env, msg: QueryMsg) -> StdResult<Binary> {
     match msg {
-        QueryMsg::GetOwner {} => to_binary(&query_owner(deps)?),
+        QueryMsg::GetOwner {} => {
+            to_binary(&query_owner(deps).map_err(|err| StdError::generic_err(err.to_string()))?)
+        }
         QueryMsg::GetConfig {} => to_binary(&query_config(deps)?),
         QueryMsg::GetRoute {
             input_denom,

contracts/liquidator/src/error.rs

@@ -6,6 +6,12 @@ pub enum ContractError {
     #[error("{0}")]
     Std(#[from] StdError),
 
+    #[error("Owner not set")]
+    NoOwner {},
+
+    #[error("Owner update error")]
+    OwnerUpdateError {},
+
     #[error("InvalidTokenShare")]
     InvalidTokenShare {},
 

contracts/liquidator/src/handle.rs

@@ -1,5 +1,5 @@
 use cosmwasm_std::{
-    Addr, BalanceResponse, BankQuery, Coin, Deps, DepsMut, Env, IbcMsg, MessageInfo, Order,
+    ensure, Addr, BalanceResponse, BankQuery, Coin, Deps, DepsMut, Env, IbcMsg, MessageInfo, Order,
     QueryRequest, Response, Uint128,
 };
 use osmosis_std::types::osmosis::poolmanager::v1beta1::{MsgSwapExactAmountIn, SwapAmountInRoute};
@@ -8,7 +8,7 @@ pub const PACKET_LIFETIME: u64 = 60 * 60; // One hour
 
 use crate::{
     error::ContractError,
-    helpers::{generate_swap_msg, validate_is_owner, validate_pool_route},
+    helpers::{generate_swap_msg, validate_pool_route},
     state::{Config, CONFIG, OWNER, ROUTING_TABLE},
 };
 
@@ -17,12 +17,11 @@ pub fn update_owner(
     info: MessageInfo,
     owner: String,
 ) -> Result<Response, ContractError> {
-    validate_is_owner(deps.as_ref(), info.sender)?;
-    let new_owner = deps.api.addr_validate(&owner)?;
-    OWNER.save(deps.storage, &new_owner)?;
-    Ok(Response::new()
-        .add_attribute("action", "change_contract_owner")
-        .add_attribute("new_owner", new_owner))
+    let valid_owner = deps.api.addr_validate(&owner)?;
+    match OWNER.execute_update_admin(deps, info, Some(valid_owner)) {
+        Ok(response) => Ok(response),
+        Err(_e) => Err(ContractError::OwnerUpdateError {}),
+    }
 }
 
 pub fn update_config(
@@ -32,7 +31,7 @@ pub fn update_config(
     ibc_channel_id: String,
     liquidation_target: String,
 ) -> Result<Response, ContractError> {
-    validate_is_owner(deps.as_ref(), info.sender)?;
+    ensure!(OWNER.is_admin(deps.as_ref(), &info.sender)?, ContractError::Unauthorized {});
     CONFIG.save(
         deps.storage,
         &Config {
@@ -119,7 +118,7 @@ pub fn set_route(
     output_denom: String,
     pool_route: Vec<SwapAmountInRoute>,
 ) -> Result<Response, ContractError> {
-    validate_is_owner(deps.as_ref(), info.sender)?;
+    ensure!(OWNER.is_admin(deps.as_ref(), &info.sender)?, ContractError::Unauthorized {});
 
     validate_pool_route(
         deps.as_ref(),

contracts/liquidator/src/helpers.rs

@@ -15,21 +15,7 @@ use osmosis_std::{
     },
 };
 
-use crate::{
-    error::ContractError,
-    state::{OWNER, ROUTING_TABLE},
-};
-
-// Validate if sender is the contract owner.
-// Returns success if sender is the owner, error otherwise.
-pub fn validate_is_owner(deps: Deps, sender: Addr) -> Result<(), ContractError> {
-    let owner = OWNER.load(deps.storage).unwrap();
-    if owner != sender {
-        Err(ContractError::Unauthorized {})
-    } else {
-        Ok(())
-    }
-}
+use crate::{error::ContractError, state::ROUTING_TABLE};
 
 // validate_pool_route validates if the pool route is valid.
 // Returns success if it is, error otherwise.

contracts/liquidator/src/query.rs

@@ -1,16 +1,20 @@
 use cosmwasm_std::{Deps, StdError, StdResult};
 
 use crate::{
+    error::ContractError,
     msg::{GetOwnerResponse, GetRouteResponse},
     state::{Config, CONFIG, OWNER, ROUTING_TABLE},
 };
 
 /// Queries contract owner from the admin
-pub fn query_owner(deps: Deps) -> StdResult<GetOwnerResponse> {
-    let owner = OWNER.load(deps.storage)?;
-    Ok(GetOwnerResponse {
-        owner: owner.into_string(),
-    })
+pub fn query_owner(deps: Deps) -> Result<GetOwnerResponse, ContractError> {
+    if let Some(owner) = OWNER.get(deps)? {
+        Ok(GetOwnerResponse {
+            owner: owner.to_string(),
+        })
+    } else {
+        Err(ContractError::NoOwner {})
+    }
 }
 
 /// Queries config

contracts/liquidator/src/state.rs

@@ -1,11 +1,11 @@
-use cosmwasm_std::Addr;
+use cw_controllers::Admin;
 use cw_storage_plus::{Item, Map};
 use osmosis_std::types::osmosis::poolmanager::v1beta1::SwapAmountInRoute;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
 pub const CONFIG: Item<Config> = Item::new("config");
-pub const OWNER: Item<Addr> = Item::new("owner");
+pub const OWNER: Admin = Admin::new("owner");
 pub const ROUTING_TABLE: Map<(&str, &str), Vec<SwapAmountInRoute>> = Map::new("routing_table");
 
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]