feat: support cmd: loading api keys for google search APIs (#1532)

refactor environment loading logic into Utils and use it for existing
provider loading, and web search where appropriate.

lua/avante/llm_tools.lua

@@ -298,7 +298,7 @@ function M.web_search(opts, on_log)
   local search_engine = Config.web_search_engine.providers[provider_type]
   if search_engine == nil then return nil, "No search engine found: " .. provider_type end
   if search_engine.api_key_name == "" then return nil, "No API key provided" end
-  local api_key = os.getenv(search_engine.api_key_name)
+  local api_key = Utils.environment.parse(search_engine.api_key_name)
   if api_key == nil or api_key == "" then
     return nil, "Environment variable " .. search_engine.api_key_name .. " is not set"
   end
@@ -350,7 +350,7 @@ function M.web_search(opts, on_log)
     local jsn = vim.json.decode(resp.body)
     return search_engine.format_response_body(jsn)
   elseif provider_type == "google" then
-    local engine_id = os.getenv(search_engine.engine_id_name)
+    local engine_id = Utils.environment.parse(search_engine.engine_id_name)
     if engine_id == nil or engine_id == "" then
       return nil, "Environment variable " .. search_engine.engine_id_name .. " is not set"
     end

lua/avante/providers/init.lua

@@ -30,61 +30,13 @@ E.cache = {}
 ---@param Opts AvanteSupportedProvider | AvanteProviderFunctor | AvanteBedrockProviderFunctor
 ---@return string | nil
 function E.parse_envvar(Opts)
-  local api_key_name = Opts.api_key_name
+  local value = Utils.environment.parse(Opts.api_key_name, Opts._shellenv)
-  if api_key_name == nil then error("Requires api_key_name") end
-
-  local cache_key = type(api_key_name) == "table" and table.concat(api_key_name, "__") or api_key_name
-
-  if E.cache[cache_key] ~= nil then return E.cache[cache_key] end
-
-  local cmd = type(api_key_name) == "table" and api_key_name or api_key_name:match("^cmd:(.*)")
-
-  local value = nil
-
-  if cmd ~= nil then
-    -- NOTE: in case api_key_name is cmd, and users still set envvar
-    -- We will try to get envvar first
-    if Opts._shellenv ~= nil and Opts._shellenv ~= "" then
-      value = os.getenv(Opts._shellenv)
-      if value ~= nil then
-        E.cache[cache_key] = value
-        vim.g.avante_login = true
-        return value
-      end
-    end
-
-    if type(cmd) == "string" then cmd = vim.split(cmd, " ", { trimempty = true }) end
-
-    Utils.debug("running command:", cmd)
-    local exit_codes = { 0 }
-    local ok, job_or_err = pcall(vim.system, cmd, { text = true }, function(result)
-      Utils.debug("command result:", result)
-      local code = result.code
-      local stderr = result.stderr or ""
-      local stdout = result.stdout and vim.split(result.stdout, "\n") or {}
-      if vim.tbl_contains(exit_codes, code) then
-        value = stdout[1]
-        E.cache[cache_key] = value
-        vim.g.avante_login = true
-      else
-        Utils.error("Failed to get API key: (error code" .. code .. ")\n" .. stderr, { once = true, title = "Avante" })
-      end
-    end)
-
-    if not ok then
-      error("failed to run command: " .. cmd .. "\n" .. job_or_err)
-      return
-    end
-  else
-    value = os.getenv(api_key_name)
-  end
-
   if value ~= nil then
-    E.cache[cache_key] = value
     vim.g.avante_login = true
+    return value
   end
 
-  return value
+  return nil
 end
 
 --- initialize the environment variable for current neovim session.

lua/avante/utils/environment.lua

@@ -0,0 +1,64 @@
+local Utils = require("avante.utils")
+
+---@class avante.utils.environment
+local M = {}
+
+---@private
+---@type table<string, string>
+M.cache = {}
+
+---Parse environment variable using optional cmd: feature with an override fallback
+---@param key_name string
+---@param override? string
+---@return string | nil
+function M.parse(key_name, override)
+  if key_name == nil then error("Requires key_name") end
+
+  local cache_key = type(key_name) == "table" and table.concat(key_name, "__") or key_name
+
+  if M.cache[cache_key] ~= nil then return M.cache[cache_key] end
+
+  local cmd = type(key_name) == "table" and key_name or key_name:match("^cmd:(.*)")
+
+  local value = nil
+
+  if cmd ~= nil then
+    if override ~= nil and override ~= "" then
+      value = os.getenv(override)
+      if value ~= nil then
+        M.cache[cache_key] = value
+        return value
+      end
+    end
+
+    if type(cmd) == "string" then cmd = vim.split(cmd, " ", { trimempty = true }) end
+
+    Utils.debug("running command:", cmd)
+    local exit_codes = { 0 }
+    local ok, job_or_err = pcall(vim.system, cmd, { text = true }, function(result)
+      Utils.debug("command result:", result)
+      local code = result.code
+      local stderr = result.stderr or ""
+      local stdout = result.stdout and vim.split(result.stdout, "\n") or {}
+      if vim.tbl_contains(exit_codes, code) then
+        value = stdout[1]
+        M.cache[cache_key] = value
+      else
+        Utils.error("failed to get key: (error code" .. code .. ")\n" .. stderr, { once = true, title = "Avante" })
+      end
+    end)
+
+    if not ok then
+      Utils.error("failed to run command: " .. cmd .. "\n" .. job_or_err)
+      return
+    end
+  else
+    value = os.getenv(key_name)
+  end
+
+  if value ~= nil then M.cache[cache_key] = value end
+
+  return value
+end
+
+return M

lua/avante/utils/init.lua

@@ -9,6 +9,7 @@ local lsp = vim.lsp
 ---@field root avante.utils.root
 ---@field file avante.utils.file
 ---@field history avante.utils.history
+---@field environment avante.utils.environment
 local M = {}
 
 setmetatable(M, {