Improve startup failures user experience

- Be clear about config errors instead of difficult stack traces
- Fix default values which should not cause startup failures

src/main/groovy/io/kamax/mxisd/config/ForwardConfig.groovy

@@ -27,7 +27,7 @@ import org.springframework.context.annotation.Configuration
 @ConfigurationProperties(prefix = "forward")
 class ForwardConfig {
 
-    private List<String> servers
+    private List<String> servers = new ArrayList<>()
 
     List<String> getServers() {
         return servers

src/main/groovy/io/kamax/mxisd/config/KeyConfig.groovy

@@ -20,6 +20,7 @@
 
 package io.kamax.mxisd.config
 
+import io.kamax.mxisd.exception.ConfigurationException
 import org.apache.commons.lang.StringUtils
 import org.springframework.beans.factory.InitializingBean
 import org.springframework.boot.context.properties.ConfigurationProperties
@@ -42,7 +43,7 @@ class KeyConfig implements InitializingBean {
     @Override
     void afterPropertiesSet() throws Exception {
         if (StringUtils.isBlank(getPath())) {
-            throw new RuntimeException("Key path must be configured!")
+            throw new ConfigurationException("key.path")
         }
     }
 

src/main/groovy/io/kamax/mxisd/config/RecursiveLookupBridgeConfig.groovy

@@ -15,7 +15,7 @@ class RecursiveLookupBridgeConfig implements InitializingBean {
     private boolean enabled
     private boolean recursiveOnly
     private String server
-    private Map<String, String> mappings
+    private Map<String, String> mappings = new HashMap<>()
 
     boolean getEnabled() {
         return enabled
@@ -51,10 +51,13 @@ class RecursiveLookupBridgeConfig implements InitializingBean {
 
     @Override
     void afterPropertiesSet() throws Exception {
+        log.info("--- Bridge integration lookups config ---")
         log.info("Enabled: {}", getEnabled())
+        if (getEnabled()) {
             log.info("Recursive only: {}", getRecursiveOnly())
-        log.info("Server: {}", getServer())
+            log.info("Fallback Server: {}", getServer())
             log.info("Mappings: {}", mappings.size())
         }
+    }
 
 }

src/main/groovy/io/kamax/mxisd/config/ServerConfig.groovy

@@ -20,6 +20,7 @@
 
 package io.kamax.mxisd.config
 
+import io.kamax.mxisd.exception.ConfigurationException
 import org.apache.commons.lang.StringUtils
 import org.springframework.beans.factory.InitializingBean
 import org.springframework.boot.context.properties.ConfigurationProperties
@@ -42,7 +43,7 @@ class ServerConfig implements InitializingBean {
     @Override
     void afterPropertiesSet() throws Exception {
         if (StringUtils.isBlank(getName())) {
-            throw new RuntimeException("Server name must be configured. Use the same realm as your Homeserver")
+            throw new ConfigurationException("server.name")
         }
     }
 

src/main/groovy/io/kamax/mxisd/exception/ConfigurationException.java

@@ -0,0 +1,11 @@
+package io.kamax.mxisd.exception;
+
+public class ConfigurationException extends RuntimeException {
+
+    private String key;
+
+    public ConfigurationException(String key) {
+        super("Invalid or empty value for configuration key " + key);
+    }
+
+}

src/main/groovy/io/kamax/mxisd/spring/ConfigurationFailureAnalyzer.java

@@ -0,0 +1,14 @@
+package io.kamax.mxisd.spring;
+
+import io.kamax.mxisd.exception.ConfigurationException;
+import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
+import org.springframework.boot.diagnostics.FailureAnalysis;
+
+public class ConfigurationFailureAnalyzer extends AbstractFailureAnalyzer<ConfigurationException> {
+
+    @Override
+    protected FailureAnalysis analyze(Throwable rootFailure, ConfigurationException cause) {
+        return new FailureAnalysis(cause.getMessage(), "Double check the key value", cause);
+    }
+
+}

src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.diagnostics.FailureAnalyzer=\
+io.kamax.mxisd.spring.ConfigurationFailureAnalyzer