Merge pull request #2 from daverolo/envars

REFACTOR: support environment variables

README.md

@@ -1,4 +1,10 @@
-# SyncLink Client PoC
+# WARNING
+
+**CURRENTLY IN DEVELOPMENT - DO NOT USE IN PRODUCTION!**
+
+You can start the SyncLink Client as described in this document however during development we continue implementing changes that could (and very likely will) make some or all of the described operations and tasks below obsolete.
+
+# SyncLink Client
 
 A very basic implementation of the [SyncLink Client](https://github.com/stereum-dev/synclink-spec/wiki/SyncLink-Client).
 
@@ -58,6 +64,40 @@ pip install -r requirements.txt
 Optional you can also specify the path to your config file or add/overwrite this arguments on the command line.
 Run `python main.py -h` for details.
 
+### Environment variables
+
+You can also configure your app by environment variables. These are identical to the command line arguments but must be prefixed with "SYLI_" and always UPPERCASE.
+For example, to specify `addr` as environment variable:
+
+```
+export SYLI_ADDR="127.0.0.1"
+python main.py
+```
+will be converted to `python main.py --addr "127.0.0.1"`.
+
+For lists, the environment variables need additionally suffixed with a number, e.g.:
+```
+export SYLI_NODE_1="10.0.0.1"
+export SYLI_NODE_2="10.0.0.2"
+python main.py
+```
+will be converted to `python main.py --node "10.0.0.1"  --node "10.0.0.2"`.
+
+If you have accidently specified an environment variable that is not suported on the command line, you need to unset the variable to avoid an error. For example:
+
+```
+export SYLI_BLA="12345"
+python main.py
+```
+will be converted to `python main.py --bla "12345"`.
+
+and of course results in the error `main.py: error: unrecognized arguments: --bla 12345`.
+
+Therefore, you'd have to remove the environment variable:
+
+```
+unset SYLI_BLA
+```
 ## Run the App
 
 Activate the virtual environment and run the app.

config/config.py

@@ -5,6 +5,9 @@
 from os.path import exists as file_exists
 from .omegaconf import OmegaConfArgparse as OmegaConf, DictConfig
 from .definition import Schema, cli_args
+from os import environ
+from sys import argv
+import re
 
 class Config():
 
@@ -26,6 +29,7 @@ def init(
         cls._schema = schema
         cls._cli_args = cli_args
         cls._strict = strict
+        cls._add_environment_variables()
         cls._setup_schema()
         cls._setup_user_config();
         #cls._setup_cli_config_omega();
@@ -37,6 +41,22 @@ def init(
     def _is_private(cls):
         if not cls._initialized: raise RuntimeError("invalid call on private method")
 
+    @classmethod
+    def _add_environment_variables(cls):
+        cls._is_private()
+        for k, v in environ.items():
+            k =  k.upper()
+            #if not k.startswith("SYLI_") or k == "SYLI_CONFIG": # all "SYLI_*" except config file
+            if not k.startswith("SYLI_"): # all "SYLI_*"
+                continue
+            # support lists as environment variables, e.g.: SYLI_NODE_1, SYLI_NODE_2 -> --node val1 --node val2
+            m = re.search(r'(.*)(_\d+)$', k)
+            if m is not None:
+                k=m.group(1)
+            argv.append(f"--{k[5:].lower()}")
+            if v != "":
+                argv.append(v)
+
     @classmethod
     def _setup_schema(cls,lala="",lolo=""):
         cls._is_private()

config/omegaconf.py

@@ -106,6 +106,8 @@ def from_argparse(
                     v['xkwargs']["default"] = ''
                     if v['xkwargs']["type"] == int:
                         v['xkwargs']["default"] = "0"
+                    if "action" in v['xkwargs'] and v['xkwargs']["action"].lower().strip() == "append":
+                        v['xkwargs']["default"] = []
                 parser.add_argument(*v["xargs"],**v["xkwargs"])
         parsed_args = vars(parser.parse_args())
         parsed_args = {k: v for k, v in parsed_args.items() if v}