[Added] Support for json file loader

Signed-off-by: amannocci <[email protected]>

README.md

@@ -264,6 +264,36 @@ temply --dotenv /path/to/dotenv /path/to/template.yml.tpl
 foobar = foobar
 ```
 
+### How to render a configuration with a json file.
+
+* Create a file where you want `/path/to/template.yml.tpl` with the following content.
+
+```text
+foo="{{ FOO }}"
+bar="{{ BAR }}"
+```
+
+* Then create a json file named `file.json` with the following content.
+```json
+[
+  {"key": "FOO", "value": "foo"},
+  {"key": "BAR", "value": "bar"}
+]
+```  
+
+* Then launch the command below to render.
+
+```bash
+temply --json-file /path/to/file.json /path/to/template.yml.tpl
+```
+
+* It will output on stdout the following content.
+
+```yaml
+foo="foo"
+bar="bar"
+```
+
 ### How to render a configuration and keep template after rendering.
 
 * By default, temply will remove template file.

temply/loaders.py

@@ -1,3 +1,4 @@
+import json
 import os
 from abc import ABC, abstractmethod
 from typing import Dict, Optional
@@ -72,3 +73,29 @@ def load(self, ref: Optional[Dict] = None) -> Dict:
             raise click.FileError(dotfile_path.abspath(), err.__str__())
 
         return ctx
+
+
+class JsonFileLoader(Loader):
+    """Environment json file loader implementation"""
+
+    def __init__(self, path: str):
+        self.__path = path
+
+    def load(self, ref: Optional[Dict] = None) -> Dict:
+        ctx = ref if ref else dict()
+
+        # Check json file is a regular file
+        json_file_path = Path(self.__path)
+        if not json_file_path.isfile():
+            raise click.FileError(json_file_path.abspath(), 'Must be a regular file')
+
+        # Process
+        try:
+            values = json.loads(json_file_path.read_text())
+            for val in values:
+                if val.get('key'):
+                    ctx[val.get('key')] = val.get('value')
+        except OSError as err:
+            raise click.FileError(json_file_path.abspath(), err.__str__())
+
+        return ctx

temply/temply.py

@@ -6,18 +6,19 @@
 from path import Path
 
 from . import __version__
-from .loaders import EnvLoader, EnvdirLoader, DotenvLoader
+from .loaders import EnvLoader, EnvdirLoader, DotenvLoader, JsonFileLoader
 
 
 @click.command('temply')
 @click.option('--allow-missing', help='Allow missing variables.', is_flag=True)
 @click.option('--keep-template', help='Keep original template file.', is_flag=True)
 @click.option('--envdir', help='Load environment variables from directory', type=click.Path())
 @click.option('--dotenv', help='Load environment variables from dotenv file', type=click.Path())
+@click.option('--json-file', help='Load environment variables from json file', type=click.Path())
 @click.option('-o', '--output-file', help='Output file path.', type=click.Path())
 @click.version_option(f'{__version__}')
 @click.argument('input_file', required=False)
-def main(allow_missing, keep_template, envdir, dotenv, output_file, input_file):
+def main(allow_missing, keep_template, envdir, dotenv, json_file, output_file, input_file):
     """Render jinja2 templates on the command line with environment variables."""
 
     # Define undefine behaviour
@@ -58,10 +59,9 @@ def main(allow_missing, keep_template, envdir, dotenv, output_file, input_file):
 
     # Compute env
     envs = EnvLoader().load()
-    if envdir:
-        envs = EnvdirLoader(envdir).load(envs)
-    if dotenv:
-        envs = DotenvLoader(dotenv).load(envs)
+    envs = EnvdirLoader(envdir).load(envs) if envdir else envs
+    envs = DotenvLoader(dotenv).load(envs) if dotenv else envs
+    envs = JsonFileLoader(json_file).load(envs) if json_file else envs
     try:
         rendering = template.render(**envs)
     except jinja2.UndefinedError as e:

tests/e2e/temply_file_test.py

@@ -106,6 +106,13 @@ def test_dotenv_template():
     assert result.exit_code == 0
 
 
+def test_json_file_template():
+    runner = CliRunner()
+    result = runner.invoke(main, args=['--keep-template', '--json-file', 'tests/fixtures/envs.json', 'tests/fixtures/envs.tpl'])
+    assert result.output == "key.secret = value-of-secret\n\n"
+    assert result.exit_code == 0
+
+
 def test_wrong_dotenv_template():
     runner = CliRunner()
     result = runner.invoke(main, args=['--keep-template', '--dotenv', 'tests/fixtures/wrong_dotenv', 'tests/fixtures/envs.tpl'],

tests/fixtures/envs.json

@@ -0,0 +1,4 @@
+[{
+  "key": "MY_key.secret",
+  "value": "value-of-secret"
+}]