prefer OPENAI_KEY because other samples use it too

Author: jordanstephens

samples/langchain/README.md

@@ -13,7 +13,7 @@ This sample is an endpoint that tells programming jokes and shows how to deploy
 ## Deploying
 
 1. Open the terminal and type `defang login`
-2. Set the environment variable `OPENAI_API_KEY` by typing `defang config set OPENAI_API_KEY`.
+2. Set the environment variable `OPENAI_KEY` by typing `defang config set OPENAI_KEY`.
 3. Type `defang compose up` in the CLI.
 4. Your app will be running within a few minutes.
 

samples/langchain/app/main.py

@@ -12,7 +12,7 @@
 )
 
 def generate_text(prompt: str) -> str:
-    api_key = os.getenv("OPENAI_API_KEY")
+    api_key = os.getenv("OPENAI_KEY")
     model = OpenAI(api_key=api_key)
     response = model.invoke(prompt)
     return response

samples/langchain/compose.yaml

@@ -4,7 +4,7 @@ services:
       context: ./app
       dockerfile: Dockerfile
     environment:
-      - OPENAI_API_KEY
+      - OPENAI_KEY
     ports:
       - target: 80
         published: 8080