fix broken file loading

* Base path was not set causing an NPR
* improve env var and command line handling
* Add sections to docs

Fig.Core/EnvironmentVarsSettingsSource.cs

@@ -7,22 +7,24 @@ namespace Fig.Core
 {
     public class EnvironmentVarsSettingsSource : SettingsSource
     {
-        private string _prefix;
-        private char _separator;
+        private readonly string _prefix;
+
+        private const char Separator = '_';
 
-        private IDictionary _vars;
+        private readonly bool _dropPrefix;
+        private readonly IDictionary _vars;
 
 
-        public EnvironmentVarsSettingsSource(string prefix = "", char separator = '_')
-            :this(Environment.GetEnvironmentVariables(), prefix, separator)
+        public EnvironmentVarsSettingsSource(string prefix, bool dropPrefix)
+            :this(Environment.GetEnvironmentVariables(), prefix, dropPrefix)
         {
         }
 
-        internal EnvironmentVarsSettingsSource(IDictionary vars, string prefix = "", char separator = '_')
+        internal EnvironmentVarsSettingsSource(IDictionary vars, string prefix, bool dropPrefix)
         {
             _vars = vars;
             _prefix = prefix;
-            _separator = separator;
+            _dropPrefix = dropPrefix;
         }
 
         /// <summary>
@@ -38,9 +40,9 @@ internal EnvironmentVarsSettingsSource(IDictionary vars, string prefix = "", cha
 
             foreach (var key in filteredKeys)
             {
-                var transformedKey = key
-                    .Remove(0, _prefix.Length)
-                    .Replace('_', '.');
+                var transformedKey = key;
+                if (_dropPrefix) transformedKey = key.Remove(0, _prefix.Length);
+                transformedKey = transformedKey.Replace(Separator, '.');
 
                 yield return (transformedKey, (string) _vars[key]);
             }

Fig.Core/SettingsBuilder.cs

@@ -12,9 +12,9 @@ private readonly CompositeSettingsDictionary _compositeDictionary
         private string _environment = "";
 
         /// <summary>
-        /// Where to look for files
+        /// Where to look for files, default is current working directory
         /// </summary>
-        private string _basePath;
+        private string _basePath = "";
 
         public Settings Build()
         {
@@ -46,9 +46,17 @@ public SettingsBuilder UseCommandLine(string[] args, string prefix = "--fig:", c
             return this;
         }
 
-        public SettingsBuilder UseEnvironmentVariables(string prefix)
+        /// <summary>
+        /// Add all the current environment variables that start with a given prefix
+        /// <remarks>The path separator (default is _) will be translated to a dot</remarks>
+        /// </summary>
+        /// <param name="prefix">For example FIG_, default is no prefix. </param>
+        /// <param name="separator">Default is _</param>
+        /// <param name="dropPrefix">When true, the prefix will not be included in the key</param>
+        /// <returns></returns>
+        public SettingsBuilder UseEnvironmentVariables(string prefix = "", bool dropPrefix = true)
         {
-            Add(new EnvironmentVarsSettingsSource(prefix).ToSettingsDictionary());
+            Add(new EnvironmentVarsSettingsSource(prefix, dropPrefix).ToSettingsDictionary());
             return this;
         }
 
@@ -66,7 +74,7 @@ protected internal void AddFileBasedSource(Func<string, SettingsSource> sourceFa
                 var source = sourceFactory.Invoke(fullPath);
                 Add(source.ToSettingsDictionary());
             }
-            else if (required) throw new FileNotFoundException("No such file", fullPath);
+            else if (required) throw new FileNotFoundException("No such file: " + fullPath, fullPath);
 
         }
 

Fig.Core/StringArraySource.cs

@@ -8,11 +8,9 @@ public class StringArraySource : SettingsSource
     {
         private readonly Regex _parser;
         private readonly string[] _args;
-        private readonly string _prefix;
 
         public StringArraySource(string[] args, string prefix, char delimiter)
         {
-            _prefix = prefix;
             _args = args;
             var pattern = 
                 "^" + 

Fig.Tests/BuilderTests.cs

@@ -0,0 +1,50 @@
+using System;
+using NUnit.Framework;
+
+namespace Fig.Test
+{
+    public class BuilderTests
+    {
+        [Test]
+        public void CanLoadRequiredFile()
+        {
+            var settings = new SettingsBuilder()
+                .UseAppSettingsJson("appsettings.json", required: true)
+                .Build();
+            Assert.DoesNotThrow(() => settings.Get("AllowedHosts"));
+        }
+
+        [Test]
+        public void CanLoadRequiredFileWithVariableExpansion()
+        {
+            Environment.SetEnvironmentVariable("ENV", "TEST");
+            var settings = new SettingsBuilder()
+                .UseEnvironmentVariables()
+                .UseAppSettingsJson("appsettings.${ENV}.json", required: true)
+                .Build();
+            Assert.DoesNotThrow(() => settings.Get("AllowedHosts"));
+        }
+
+        [Test]
+        public void CanReferenceOptionalNonExistentFile()
+        {
+            Assert.DoesNotThrow(() =>
+            {
+                var settings = new SettingsBuilder()
+                    .UseAppSettingsJson("nonexistent.json", required: false)
+                    .Build();            
+            });
+        }
+
+        [Test]
+        public void CanReferenceOptionalNonExistentFileWithVariableExpansion()
+        {
+            Assert.DoesNotThrow(() =>
+            {
+                var settings = new SettingsBuilder()
+                    .UseAppSettingsJson("nonexistent.${ENV}.json", required: false)
+                    .Build();
+            });
+        }
+    }
+}

Fig.Tests/CommandLineArgsTests.cs

@@ -0,0 +1,35 @@
+using NUnit.Framework;
+
+namespace Fig.Test
+{
+    public class CommandLineArgsTests
+    {
+        [Test]
+        public void WithPrefix()
+        {
+            var args = new[] {"--fig:Color=red", "--fig:Size=4", "other=20"};
+            var settings = new SettingsBuilder().UseCommandLine(args).Build();
+            var colorExists = settings.SettingsDictionary.TryGetValue("Color", "", out _);
+            var sizeExists = settings.SettingsDictionary.TryGetValue("Size", "", out _);
+            var prefixlessNotPresent = settings.SettingsDictionary.TryGetValue("Other", "", out _);
+
+            Assert.True(colorExists);
+            Assert.True(sizeExists);
+            Assert.False(prefixlessNotPresent);
+        }
+
+        [Test]
+        public void WithoutPrefix()
+        {
+            var args = new[] {"myApp.Color=red", "Size=4", "--other=20"};
+            var settings = new SettingsBuilder().UseCommandLine(args, prefix:"").Build();
+            var colorExists = settings.SettingsDictionary.TryGetValue("myApp.Color", "", out _);
+            var sizeExists = settings.SettingsDictionary.TryGetValue("Size", "", out _);
+            var nonMatchingKey = settings.SettingsDictionary.TryGetValue("--Other", "", out _);
+
+            Assert.True(colorExists);
+            Assert.True(sizeExists);
+            Assert.False(nonMatchingKey);
+        }
+    }
+}

Fig.Tests/EnvironmentVarsSourceTests.cs

@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using Fig.Core;
+using NUnit.Framework;
+
+namespace Fig.Test
+{
+    public class EnvironmentVarsSourceTests
+    {
+        [Test]
+        public void WithDroppedPrefix()
+        {
+            var dictionary = new Dictionary<string, string>()
+            {
+                ["FIG_A"] = "fig.a",
+
+            };
+            var source = new EnvironmentVarsSettingsSource(dictionary, "FIG_", dropPrefix: true);
+            var settings = source.ToSettingsDictionary();
+            Assert.True(settings.ContainsKey("a"));
+        }
+
+        [Test]
+        public void WithRetainedPrefix()
+        {
+            var dictionary = new Dictionary<string, string>()
+            {
+                ["FIG_A"] = "fig.a",
+
+            };
+            var source = new EnvironmentVarsSettingsSource(dictionary, "FIG_", dropPrefix: false);
+            var settings = source.ToSettingsDictionary();
+            Assert.True(settings.ContainsKey("fig.a"));
+        }
+    }
+}

Fig.Tests/Fig.Tests.csproj

@@ -24,6 +24,9 @@
     <None Include="appsettings.json">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </None>
+    <None Update="appsettings.TEST.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <None Update="appsettings.json">

Fig.Tests/appsettings.TEST.json

@@ -0,0 +1,26 @@
+{
+  "Timeout" :  42,
+  "ConnectionStrings": {
+    "DefaultConnection": "DataSource=app.db"
+  },
+  "Servers" :  ["10.0.0.1", "10.0.0.2"],
+  "Logging": {
+    "LogLevel": {
+      "Default": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "Simpsons" :  [
+      { "Name" :  "Bart", "Age" :  12},
+      { "Name" :  "Homer", "Age" :  35}
+  ],
+
+  "EnvQualified:PROD" : {
+    "a" : 1,
+    "b" : 1
+  },
+  "EnvQualified:TEST" : {
+     "a" : 2,
+    "b" : 2
+  }
+}

README.md

@@ -188,6 +188,58 @@ Datasource.A.name
 Datasource.A.connectionstring
 ```
 
+## Environment variables
+Given these environment variables:
+```bash
+export ENV=TEST
+export FIG_TIMEOUT=30
+export FIG_LOGGING_LOGLEVEL_DEFAULT=Warning
+export MYAPP_COLOR=Red
+export MYAPP_ENDPOINT=10.0.0.1:3001
+```
+`builder.UseEnvironmentVariables(prefix: "FIG_", dropPrefix:true)` yields:
+```
+TIMEOUT
+LOGGING.LOGLEVEL.DEFAULT
+```
+`builder.UseEnvironmentVariables(prefix: "MYAPP_", dropPrefix:false)` yields:
+```
+MYAPP.COLOR
+MYAPP.ENDPOINT
+```
+
+`builder.UseEnvironmentVariables()` yields:
+```
+ENV
+FIG.TIMEOUT
+FIG.LOGGING.LOGLEVEL.DEFAULT
+MYAPP.COLOR
+MYAPP.ENDPOINT
+```
+
+
+## Command line
+Fig can take key/value paires passed on the command line. The default prefix is "--fig:" and default separator is "="
+```c#
+//Given
+string[] args = new []{
+   "--fig:ENV=Test",
+   "--fig:Timeout=30",
+   "retries=3"};
+```
+
+`settingsBuilder.UseCommandLine(args)` yields:
+
+```
+ENV
+Timeout
+```
+
+and `settingsBuilder.UseCommandLine(args, prefix: "")` yields:
+```
+retries
+``` 
+
 # Combining sources
 Use the `SettingsBuilder` to add sources in order of precedence. 
 Settings in above layers override settings with the same key in
@@ -196,7 +248,7 @@ lower layers. Note that this is the opposite order of `Microsoft.Extensions.Conf
 ```c#
    var settings = new SettingsBuilder()
     .UseCommandLine(args)
-    .UseEnvironmentVariables()
+    .UseEnvironmentVariables(prefix: "FIG_", dropPrefix:false)
     .UseAppSettingsJson("appSettings.${ENV}.json", optional:true)
     .UseAppSettingsJson("appSettings.json")
     .Build<Settings>();

appveyor.yml

@@ -1,4 +1,4 @@
-version: 1.7.{build}
+version: 1.8.{build}
 image: Ubuntu1804
 assembly_info:
   patch: true