Randomize charge api token's getenv fallback value

If the env var is not defined, fall back to a random string. However,
note the random string won't work over gunicorn if using multiple
workers. In this case, it is necessary to define the env var.

docker-compose.yml

@@ -15,6 +15,7 @@ services:
     environment:
       - CHARGE_ROOT=http://api-token:mySecretToken@blc:9112
       - CALLBACK_URI_ROOT=http://localhost:9292
+      - CHARGE_API_TOKEN=mySecretToken
       - ENV=development
       - REDIS_URI=redis://redis:6379
     volumes:

server/constants.py

@@ -1,4 +1,5 @@
 import os
+import uuid
 import yaml
 from enum import Enum
 
@@ -83,7 +84,7 @@ MESSAGE_FILE_RETENTION_TIME_DAYS = 31
 SERVER_PORT = 9292
 CALLBACK_URI_ROOT = os.getenv('CALLBACK_URI_ROOT',
                               "http://localhost:{}".format(SERVER_PORT))
-CHARGE_API_TOKEN = os.getenv('CHARGE_API_TOKEN', 'mySecretToken')
+CHARGE_API_TOKEN = os.getenv('CHARGE_API_TOKEN', str(uuid.uuid4()))
 LIGHTNING_WEBHOOK_KEY = hmac_sha256_digest('charged-token', CHARGE_API_TOKEN)
 
 CHARGE_ROOT = os.getenv('CHARGE_ROOT',

terraform/modules/blc/cloud-init/blc.yaml

@@ -237,6 +237,7 @@ write_files:
             -e "ENV=production" \
             -e "CHARGE_ROOT=http://api-token:${charge_token}@localhost:9112" \
             -e "CALLBACK_URI_ROOT=http://localhost:9292" \
+            -e "CHARGE_API_TOKEN=${charge_token}" \
             -e "MIN_PER_BYTE_BID=1" \
             -e "REDIS_URI=redis://localhost:6379" \
             "${ionosphere_docker}"