feat(config): env var override

Author: roshii

src/jmclient/configure.py

@@ -91,8 +91,10 @@ def jm_single() -> AttributeDict:
                     'POLICY': ['absurd_fee_per_kb', 'taker_utxo_retries',
                                'taker_utxo_age', 'taker_utxo_amtpercent']}
 
-_DEFAULT_INTEREST_RATE = "0.015"
+_ENV_VAR_PREFIX = "JM_"
+_SECTIONS_WITH_SUBSECTIONS = {"MESSAGING"}
 
+_DEFAULT_INTEREST_RATE = "0.015"
 _DEFAULT_BONDLESS_MAKERS_ALLOWANCE = "0.125"
 
 defaultconfig = \
@@ -673,9 +675,8 @@ def _remove_unwanted_default_settings(config: ConfigParser) -> None:
         if section.startswith('MESSAGING:'):
             config.remove_section(section)
 
-def load_program_config(config_path: str = "", bs: Optional[str] = None,
-                        plugin_services: List[JMPluginService] = []) -> None:
-    global_singleton.config.read_file(io.StringIO(defaultconfig))
+
+def set_paths(config_path: str = "") -> None:
     if not config_path:
         config_path = lookup_appdata_folder(global_singleton.APPNAME)
     # we set the global home directory, but keep the config_path variable
@@ -692,29 +693,70 @@ def load_program_config(config_path: str = "", bs: Optional[str] = None,
     if not os.path.exists(os.path.join(global_singleton.datadir, "cmtdata")):
         os.makedirs(os.path.join(global_singleton.datadir, "cmtdata"))
     global_singleton.config_location = os.path.join(
-        global_singleton.datadir, global_singleton.config_location)
+        global_singleton.datadir, global_singleton.config_location
+    )
 
-    _remove_unwanted_default_settings(global_singleton.config)
+
+def read_config_file() -> bool:
     try:
-        loadedFiles = global_singleton.config.read(
-            [global_singleton.config_location])
+        loaded = global_singleton.config.read([global_singleton.config_location])
     except UnicodeDecodeError:
-        jmprint("Error loading `joinmarket.cfg`, invalid file format.",
-            "info")
+        jmprint("Error loading `joinmarket.cfg`, invalid file format.", "info")
         sys.exit(EXIT_FAILURE)
+    return len(loaded) == 1
+
 
+def write_config_file(config: str = defaultconfig) -> bool:
+    with open(global_singleton.config_location, "w") as configfile:
+        configfile.write(config)
+    jmprint(
+        "Created a new `joinmarket.cfg`. Please review and adopt the "
+        "settings and restart joinmarket.",
+        "info",
+    )
+    sys.exit(EXIT_FAILURE)
+
+
+def override(config: ConfigParser, bs: Optional[str] = None) -> None:
+    _remove_unwanted_default_settings(config)
     # Hack required for bitcoin-rpc-no-history and probably others
     # (historicaly electrum); must be able to enforce a different blockchain
     # interface even in default/new load.
     if bs:
-        global_singleton.config.set("BLOCKCHAIN", "blockchain_source", bs)
-    # Create default config file if not found
-    if len(loadedFiles) != 1:
-        with open(global_singleton.config_location, "w") as configfile:
-            configfile.write(defaultconfig)
-        jmprint("Created a new `joinmarket.cfg`. Please review and adopt the "
-              "settings and restart joinmarket.", "info")
-        sys.exit(EXIT_FAILURE)
+        config.set("BLOCKCHAIN", "blockchain_source", bs)
+
+
+def override_from_environment(config: ConfigParser) -> ConfigParser:
+    for key, value in os.environ.items():
+        if key.startswith(_ENV_VAR_PREFIX):
+            key = key.removeprefix(_ENV_VAR_PREFIX)
+            section, key = key.split("_", 1)
+            if section in _SECTIONS_WITH_SUBSECTIONS:
+                sub, key = key.split("_", 1)
+                section = f"{section}:{sub.lower()}"
+            key = key.lower()
+            if not config.has_section(section):
+                config.add_section(section)
+            log.info(f"Overriding [{section}] {key}={value}")
+            config.set(section, key, value)
+    return config
+
+
+def load_program_config(
+    config_path: str = "",
+    bs: Optional[str] = None,
+    plugin_services: List[JMPluginService] = [],
+    from_environment: bool = False,
+) -> None:
+    set_paths(config_path)
+    global_singleton.config.read_string(defaultconfig)
+    if from_environment:
+        override_from_environment(global_singleton.config)
+    else:
+        override(global_singleton.config, bs)
+        # Create default config file if not found
+        if not read_config_file():
+            write_config_file()
 
     loglevel = global_singleton.config.get("LOGGING", "console_log_level")
     try:

test/jmclient/test_configure.py

@@ -1,8 +1,15 @@
 '''test configure module.'''
 
+import os
+from configparser import ConfigParser
+
 import pytest
-from jmclient import load_test_config, jm_single
-from jmclient.configure import get_blockchain_interface_instance
+
+from jmclient import jm_single, load_test_config
+from jmclient.configure import (
+    get_blockchain_interface_instance,
+    override_from_environment,
+)
 
 pytestmark = pytest.mark.usefixtures("setup_regtest_bitcoind")
 
@@ -35,3 +42,33 @@ def test_blockchain_sources():
         else:
             get_blockchain_interface_instance(jm_single().config)
     load_test_config()
+
+
+def test_override_from_environment():
+    config = ConfigParser()
+    config.add_section("BLOCKCHAIN")
+    config.add_section("POLICY")
+
+    overrides = {
+        "JM_BLOCKCHAIN_NETWORK": "testnet",
+        "JM_POLICY_TX_FEES": "1000",
+        "JM_MESSAGING_ONION_TYPE": "onion",
+        "JM_DAEMON_DAEMON_PORT": "27184",
+    }
+    for key, value in overrides.items():
+        os.environ[key] = value
+
+    try:
+        # Override config from environment
+        override_from_environment(config)
+
+        # Verify overrides were applied
+        assert config.get("BLOCKCHAIN", "network") == "testnet"
+        assert config.get("POLICY", "tx_fees") == "1000"
+        assert config.get("MESSAGING:onion", "type") == "onion"
+        assert config.get("DAEMON", "daemon_port") == "27184"
+    finally:
+        # Clean up environment variables
+        for key in overrides.keys():
+            if key in os.environ:
+                del os.environ[key]