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Configuring with Environment Variables

The purpose of this demonstration is to show the open-aea framework can dynamically configure agents from environment variables.

A full break down of the development flow is covered within the Development Quickstart.

It is highly recommended that developers begin by following the quick start!

After you have followed the quick start, create a HTTP Echo Agent.

It is assumed that developers are within a pipenv virtual environment.

Notice, that the configuration of the AEA is as so;

agent_name: http_echo
author: open_aea
version: 0.1.0
license: Apache-2.0
description: Http echo agent configured with default variables.
aea_version: '>=1.3.0, <2.0.0'
fingerprint: {}
fingerprint_ignore_patterns: []
connections:
- valory/http_server:0.22.0
contracts: []
protocols:
- fetchai/default:1.0.0
- valory/http:1.0.0
- open_aea/signing:1.0.0
skills:
- fetchai/http_echo:0.20.0
default_ledger: ethereum
required_ledgers:
- ethereum
default_routing: {}
connection_private_key_paths: {}
private_key_paths:
  ethereum: ethereum_private_key.txt
logging_config:
  disable_existing_loggers: false
  version: 1
dependencies:
  open-aea-ledger-ethereum: {}
default_connection: null
---
public_id: valory/http_server:0.22.0
type: connection
config:
  host: ${HOST:str:localhost}
  port: ${PORT:int:5000}
  target_skill_id: ${TARGET_SKILL:str:fetchai/http_echo:0.20.0}

Notice how the valory/http_server:0.22.0 has a number of override parameters specified: 

host: ${HOST:str:localhost}
port: ${PORT:int:5000}
target_skill_id: ${TARGET_SKILL:str:fetchai/http_echo:0.20.0}

Please notice the values provided to the over-rides. The syntax is as follows;

${ENVIRONMENT_VALUE:PYTHON_TYPE:DEFAULT_VALUE}

We can use environment variables to override these default values.

First run the agent with the default port (assuming you are within the agent directory created within HTTP Echo Agent) as so:

aea run --aev

The --aev flag specifies to apply environment overrides

The AEA will then start a web server as so:

    _     _____     _
   / \   | ____|   / \
  / _ \  |  _|    / _ \
 / ___ \ | |___  / ___ \
/_/   \_\|_____|/_/   \_\

v1.4.0

Starting AEA 'http_echo' in 'async' mode...
info: [http_echo] HTTP Server has connected to port: 5000.
info: [http_echo] Start processing messages...

We can interact with this server using curl in another terminal as so;

curl localhost:5000
{"tom": {"type": "cat", "age": 10}}

In order to use the environment overrides, we must first stop our AEA. Once the AEA is stopped:

export PORT=8081
aea run --aev
    _     _____     _
   / \   | ____|   / \
  / _ \  |  _|    / _ \
 / ___ \ | |___  / ___ \
/_/   \_\|_____|/_/   \_\

v1.4.0

Starting AEA 'http_echo' in 'async' mode...
info: [http_echo] HTTP Server has connected to port: 8081.
info: [http_echo] Start processing messages...

We can confirm that we are now serving on a different port as so;

curl localhost:8081
{"tom": {"type": "cat", "age": 10}}

Congratulations! You have just used an AEA successfully as a web server!

Tear Down

aea delete http_echo