feat: support for OPENAI_BASE_URL env var (64bit#480)

* retrieve openai_api_base from env var OPENAI_API_BASE

* Update async-openai/src/config.rs

* Update async-openai/README.md

* Update async-openai/README.md

* Update async-openai/src/config.rs

* Update async-openai/README.md

* Update async-openai/src/config.rs

---------

Co-authored-by: Antoine Rouquette <[email protected]>
Co-authored-by: Himanshu Neema <[email protected]>
(cherry picked from commit 73b4735)

Author: 3 people

async-openai/src/config.rs

@@ -68,7 +68,8 @@ pub struct OpenAIConfig {
 impl Default for OpenAIConfig {
     fn default() -> Self {
         Self {
-            api_base: OPENAI_API_BASE.to_string(),
+            api_base: std::env::var("OPENAI_BASE_URL")
+                .unwrap_or_else(|_| OPENAI_API_BASE.to_string()),
             api_key: std::env::var("OPENAI_API_KEY")
                 .or_else(|_| {
                     std::env::var("OPENAI_ADMIN_KEY").inspect(|_admin_key| {
@@ -85,7 +86,7 @@ impl Default for OpenAIConfig {
 }
 
 impl OpenAIConfig {
-    /// Create client with default [OPENAI_API_BASE] url and default API key from OPENAI_API_KEY env var
+    /// Create client with default [OPENAI_API_BASE] url (can also be changed with OPENAI_BASE_URL env var) and default API key from OPENAI_API_KEY env var
     pub fn new() -> Self {
         Default::default()
     }