chore(core): rework PDF-AS-Web configuration integration with Spring Boot context

2 files changed, 90 insertions, 41 deletions

diff --git a/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/PdfAsWeb.java b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/PdfAsWeb.java
index 75042176..85d94a7f 100644
--- a/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/PdfAsWeb.java
+++ b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/PdfAsWeb.java
@@ -1,57 +1,35 @@
 package at.gv.egiz.pdfas.web;
 
-import lombok.val;
-import org.jetbrains.annotations.NotNull;
-import org.springframework.boot.EnvironmentPostProcessor;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
-import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.MapPropertySource;
 
-import java.util.HashMap;
+import at.gv.egiz.pdfas.web.config.PdfAsSpringBootApplicationContextInitializer;
+import lombok.extern.slf4j.Slf4j;
 
+@Slf4j
 @SpringBootApplication
 public class PdfAsWeb extends SpringBootServletInitializer {
 
-  // registered in resources/META-INF/spring.factories
-  public static class DefaultProperties implements EnvironmentPostProcessor {
-    @Override
-    public void postProcessEnvironment(
-        @NotNull ConfigurableEnvironment environment, @NotNull SpringApplication application)
-    {
-      /*
-        == DEFAULT PROPERTIES ==
-          these are properties with the lowest precedence
-          so anything else (pdf-as-web.properties, system params, etc) can override them
-      */
-      val defaultProperties = new HashMap<String, Object>();
-      // set the default application name
-      defaultProperties.put("spring.application.name", "PDF-AS Web");
-      // disable spring boot admin client by default
-      defaultProperties.put("spring.boot.admin.client.enabled", "false");
-      // compatibility layer: map the old logback.configurationFile to the new logging.config
-      val legacyLogProperty = System.getProperty("logback.configurationFile");
-      if (legacyLogProperty != null) {
-        defaultProperties.put("logging.config", legacyLogProperty);
-      }
-
-      /*
-        == END DEFAULT PROPERTIES ==
-      */
-
-
-      environment.getPropertySources().addLast(new MapPropertySource("pdf-as-web-defaults", defaultProperties));
-    }
-  }
-
   @Override
-  protected @NotNull SpringApplicationBuilder configure(@NotNull SpringApplicationBuilder application) {
-    return application.sources(PdfAsWeb.class);
+  protected SpringApplicationBuilder createSpringApplicationBuilder() {      
+    SpringApplicationBuilder builder = new SpringApplicationBuilder();
+    builder.initializers(new PdfAsSpringBootApplicationContextInitializer());    
+    builder.sources(PdfAsWeb.class);
+    return builder;
+    
   }
-
+  
   public static void main(String[] args) {
-    SpringApplication.run(PdfAsWeb.class, args);
+    log.info("=============== Initializing Spring-Boot context! ===============");
+    final SpringApplication springApp = new SpringApplication(PdfAsWeb.class);
+    springApp.addInitializers(new PdfAsSpringBootApplicationContextInitializer());
+    
+    log.debug("Run SpringBoot initialization process ... ");
+    springApp.run(args);
+    
+    log.info("Initialization of PDF-AS-Web finished.");
+
   }
 }
diff --git a/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/config/PdfAsSpringBootApplicationContextInitializer.java b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/config/PdfAsSpringBootApplicationContextInitializer.java
new file mode 100644
index 00000000..184030d2
--- /dev/null
+++ b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/config/PdfAsSpringBootApplicationContextInitializer.java
@@ -0,0 +1,71 @@
+package at.gv.egiz.pdfas.web.config;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Properties;
+
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.PropertiesPropertySource;
+
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class PdfAsSpringBootApplicationContextInitializer
+    implements ApplicationContextInitializer<ConfigurableApplicationContext> {
+
+  private static final String SYSTEMD_PROP_NAME = "pdf-as-web.conf";
+  private static final String FILE_PREFIX = "file:";
+
+  @Override
+  public void initialize(ConfigurableApplicationContext applicationContext) {
+    final String rawConfigPath = System.getProperty(SYSTEMD_PROP_NAME);
+
+    if (StringUtils.isBlank(rawConfigPath)) {
+      log.info("No SystemD property '{}' found. No external configuration loaded.", SYSTEMD_PROP_NAME);
+      return;
+    }
+
+    log.debug("Found configuration source from SystemD property '{}'.", SYSTEMD_PROP_NAME);
+
+    final String configPath = stripFilePrefix(rawConfigPath);
+    injectConfiguration(Path.of(configPath), applicationContext);
+  }
+
+  private static String stripFilePrefix(String configPath) {
+    return configPath.startsWith(FILE_PREFIX)
+        ? configPath.substring(FILE_PREFIX.length())
+        : configPath;
+  }
+
+  private void injectConfiguration(
+      Path configPath,
+      ConfigurableApplicationContext applicationContext) {
+
+    if (!Files.isRegularFile(configPath)) {
+      log.error("Configuration from SystemD property '{}' does not exist or is not a file: {}",
+          SYSTEMD_PROP_NAME, configPath);
+      return;
+    }
+
+    try (InputStream inputStream = Files.newInputStream(configPath)) {
+      final Properties properties = new Properties();
+      properties.load(inputStream);
+
+      applicationContext
+          .getEnvironment()
+          .getPropertySources()
+          .addFirst(new PropertiesPropertySource(SYSTEMD_PROP_NAME, properties));
+
+      log.info("Loaded configuration source from SystemD property '{}': {}",
+          SYSTEMD_PROP_NAME, configPath);
+
+    } catch (IOException e) {
+      log.error("Configuration from SystemD property '{}' at location '{}' cannot be loaded.",
+          SYSTEMD_PROP_NAME, configPath, e);
+    }
+  }
+}
\ No newline at end of file