Hermes (python)

Configuration manager for python services. This module can be used to find and load configuration files based on MICROSERVICE_ENV (--env) environment variable. Hermes looks for specified config file in entire CONFIG_PATH and loads an appropriate one.

Usage

Import module:

from armada import hermes

One file at a time

Load myconfig.json.

hermes.get_config('myconfig.json') 
{"db_host: "localhost", "db_port": 3306}

If config file is not a json type, plain string is returned. Load myconfig.notjson.

hermes.get_config('myconfig.notjson') 
"{\"db_host\": \"localhost\", \"db_port\": 3306}"

If configuration file does not exist in CONFIG_PATH None is returned.

hermes.get_config('im_sure_it_doesnt_exist')
None

Merged configs

merged configs can load for now only json files

Load myconfig.json.

hermes.get_merged_config('myconfig.json') 
{"db_host: "localhost", "db_port": 3306}

How it works:

if CONFIG_PATH is set to: /example/config/:/example/config/dev/
merged config will look for file in:

• /example/config/myconfig.json
• /example/config/dev/myconfig.json
• /example/config/local/myconfig.json

1. if all of them exists
   /example/config/myconfig.json is overwritten by /example/config/dev/myconfig.json, and then result is overwritten by /example/config/local/myconfig.json

2. if only one of them exists it will work as hermes.get_config

3. if configuration file does not exist, an empty dict is returned.

   hermes.get_merged_config('myconfig.json') 
   {"db_host: "localhost", "db_port": 3306}
   

if additionaly TEST_ENV is set to true, merged config will look for file in:

• /example/config/myconfig.json
• /example/config/dev/myconfig.json
• /example/config/test/myconfig.json

1. if all of them exists
   /example/config/myconfig.json is overwritten by /example/config/dev/myconfig.json, and then result is overwritten by /example/config/test/myconfig.json

2. rest is as when TEST_ENV is never set.

Secrets manager

Added in version 1.4.

Usage

1. Config must be a json file.
2. Add secrets_manager block to config

   "secrets_manager": {
     "name": "production-example"
   }
   

3. Add value for specific key in form:

   secrets_manager:KEY[:TYPE]
   "password": "secrets_manager:orders-db/password"
   

4. Install boto3 to get secrets

   from boto3 import client
   
   sm_client = client('secretsmanager')
   
   hermes.get_merged_config(
     key='config.json',
     secrets_manager_client=sm_client,
   )
   

If you didn't put client as a parameter, but you have installed boto3 we create client for you.

From version 1.7 armada-py supports AWS CLI profiles. If you want to use them to get secrets simply add "aws_profile".

  "secrets_manager": {
    "name": "production-example",
    "aws_profile": "production"
  }

KEY in secrets manager can be totally different then key in config.

Default type is 'str'. You don't need to add ':str' to value. Otherwise you need to specify data type.

Supported types

• str
• int
• bool
• list
• dict
• file

File type - this will create a file with content from secrets manager. Filename will be KEY FROM CONFIG . Value in config for this key will be absolute path to file.

Types usage examples:

  "blacklisted_ips": "secrets_manager:cheater-ips:list"
  "ssh_key": "secrets_manager:orders-db/ssh-proxy/ci-deploy.key:file"