Allow loading config from environment variables

rchodava · May 5, 2016 · a29e9b7 · a29e9b7
1 parent bf47791
commit a29e9b7
Show file tree

Hide file tree

Showing 3 changed files with 121 additions and 14 deletions.
diff --git a/core/pom.xml b/core/pom.xml
@@ -115,6 +115,11 @@
             <version>1.10.19</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-rules</artifactId>
+            <version>1.16.0</version>
+        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-core</artifactId>

diff --git a/core/src/main/java/org/chodavarapu/datamill/configuration/ConfigurationBuilder.java b/core/src/main/java/org/chodavarapu/datamill/configuration/ConfigurationBuilder.java
@@ -9,6 +9,7 @@
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.Map;
 import java.util.function.Consumer;
 
 /**
@@ -45,6 +46,11 @@ public ConfigurationBuilder<T> ifSystemPropertyExists(String name,
                                                           Consumer<ConfigurationBuilder<T>> configuration,
                                                           Consumer<ConfigurationBuilder<T>> elseConfiguration) {
         String value = System.getProperty(name);
+
+        if (value == null) {
+            value = System.getenv(name);
+        }
+
         if (value != null) {
             if (configuration != null) {
                 configuration.accept(this);
@@ -60,6 +66,11 @@ public ConfigurationBuilder<T> ifSystemPropertyExists(String name,
 
     private String getSystemProperty(String name, boolean required) {
         String value = System.getProperty(name);
+
+        if (value == null) {
+            value = System.getenv(name);
+        }
+
         if (value == null && required) {
             throw new IllegalStateException("Expected " + name + " to be found in the system properties list!");
         }
@@ -206,4 +217,24 @@ public <P> ConfigurationBuilder<T> fromLocalAddress(Consumer<T> propertyInvoker,
         bean.set(propertyInvoker, derivation.call(localAddress));
         return this;
     }
+
+    public ConfigurationBuilder<T> printSystemProperties() {
+        StringBuilder properties = new StringBuilder();
+        for (Map.Entry<Object, Object> property : System.getProperties().entrySet()) {
+            properties.append(property.getKey() != null ? property.getKey().toString() : "<null>");
+            properties.append("=");
+            properties.append(property.getValue() != null ? property.getValue().toString() : "<null>");
+            properties.append("; ");
+        }
+
+        for (Map.Entry<String, String> property : System.getenv().entrySet()) {
+            properties.append(property.getKey() != null ? property.getKey() : "<null>");
+            properties.append("=");
+            properties.append(property.getValue() != null ? property.getValue() : "<null>");
+            properties.append("; ");
+        }
+
+        logger.debug("System Properties: { {} }", properties);
+        return this;
+    }
 }
diff --git a/core/src/test/java/org/chodavarapu/datamill/configuration/ConfigurationBuilderTest.java b/core/src/test/java/org/chodavarapu/datamill/configuration/ConfigurationBuilderTest.java
@@ -1,7 +1,9 @@
 package org.chodavarapu.datamill.configuration;
 
 import org.chodavarapu.datamill.reflection.OutlineBuilder;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.contrib.java.lang.system.EnvironmentVariables;
 
 import java.net.InetAddress;
 
@@ -23,13 +25,38 @@ public void setProperty(String property) {
         }
     }
 
+    @Rule public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
+
     @Test
-    public void build() throws Exception {
-        System.setProperty("test", "value");
-        System.setProperty("test2", "_value2");
-        System.setProperty("test3", "_value3");
-        System.setProperty("test4", "_value4");
-        System.setProperty("test5", "_value5");
+    public void buildFromMiscellaneous() throws Exception {
+        Configuration configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .configure(c -> c.setProperty("set"))
+                .get();
+        assertEquals("set", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .configure((b, c) -> c.setProperty("builder_set"))
+                .get();
+        assertEquals("builder_set", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromLocalAddress(c -> c.getProperty())
+                .get();
+        assertEquals(InetAddress.getLocalHost().getHostAddress(), configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromLocalAddress(c -> c.getProperty(), a -> a + "_derived")
+                .get();
+        assertEquals(InetAddress.getLocalHost().getHostAddress() + "_derived", configuration.getProperty());
+    }
+
+    @Test
+    public void buildFromEnvironmentVariables() throws Exception {
+        environmentVariables.set("test", "value");
+        environmentVariables.set("test2", "_value2");
+        environmentVariables.set("test3", "_value3");
+        environmentVariables.set("test4", "_value4");
+        environmentVariables.set("test5", "_value5");
 
         Configuration configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
                 .fromRequiredSystemProperty(c -> c.getProperty(), "test")
@@ -70,29 +97,68 @@ public void build() throws Exception {
         assertEquals("value_value2_value3_value4_value5_derived", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
-                .configure(c -> c.setProperty("set"))
+                .ifSystemPropertyExists("test", b -> b.configure(c -> c.setProperty("exists")))
                 .get();
-        assertEquals("set", configuration.getProperty());
+        assertEquals("exists", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
-                .configure((b, c) -> c.setProperty("builder_set"))
+                .ifSystemPropertyExists("test_non_existent",
+                        b -> b.configure(c -> c.setProperty("exists")),
+                        b -> b.configure(c -> c.setProperty("non_existent")))
                 .get();
-        assertEquals("builder_set", configuration.getProperty());
+        assertEquals("non_existent", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
                 .configure((b, c) -> c.setProperty(b.getRequiredSystemProperty("test").asString()))
                 .get();
         assertEquals("value", configuration.getProperty());
+    }
+
+    @Test
+    public void buildFromSystemProperties() throws Exception {
+        System.setProperty("test", "value");
+        System.setProperty("test2", "_value2");
+        System.setProperty("test3", "_value3");
+        System.setProperty("test4", "_value4");
+        System.setProperty("test5", "_value5");
+
+        Configuration configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromRequiredSystemProperty(c -> c.getProperty(), "test")
+                .get();
+        assertEquals("value", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
-                .fromLocalAddress(c -> c.getProperty())
+                .fromOptionalSystemProperty(c -> c.getProperty(), "test_unknown", "default")
                 .get();
-        assertEquals(InetAddress.getLocalHost().getHostAddress(), configuration.getProperty());
+        assertEquals("default", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
-                .fromLocalAddress(c -> c.getProperty(), a -> a + "_derived")
+                .fromRequiredSystemProperty(c -> c.getProperty(), "test", v -> v + "_derived")
                 .get();
-        assertEquals(InetAddress.getLocalHost().getHostAddress() + "_derived", configuration.getProperty());
+        assertEquals("value_derived", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromRequiredSystemProperties(c -> c.getProperty(), "test", "test2", (v1, v2) -> v1 + v2 + "_derived")
+                .get();
+        assertEquals("value_value2_derived", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromRequiredSystemProperties(c -> c.getProperty(), "test", "test2", "test3",
+                        (v1, v2, v3) -> v1 + v2 + v3 + "_derived")
+                .get();
+        assertEquals("value_value2_value3_derived", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromRequiredSystemProperties(c -> c.getProperty(), "test", "test2", "test3", "test4",
+                        (v1, v2, v3, v4) -> v1 + v2 + v3 + v4 + "_derived")
+                .get();
+        assertEquals("value_value2_value3_value4_derived", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .fromRequiredSystemProperties(c -> c.getProperty(), "test", "test2", "test3", "test4", "test5",
+                        (v1, v2, v3, v4, v5) -> v1 + v2 + v3 + v4 + v5 + "_derived")
+                .get();
+        assertEquals("value_value2_value3_value4_value5_derived", configuration.getProperty());
 
         configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
                 .ifSystemPropertyExists("test", b -> b.configure(c -> c.setProperty("exists")))
@@ -105,5 +171,10 @@ public void build() throws Exception {
                         b -> b.configure(c -> c.setProperty("non_existent")))
                 .get();
         assertEquals("non_existent", configuration.getProperty());
+
+        configuration = new ConfigurationBuilder<>(new OutlineBuilder().wrap(new Configuration()))
+                .configure((b, c) -> c.setProperty(b.getRequiredSystemProperty("test").asString()))
+                .get();
+        assertEquals("value", configuration.getProperty());
     }
 }