com.sap.cloud.yaas.servicesdk.apiconsole.utils.AppInfoReader Maven / Gradle / Ivy

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/*
 * © 2016 SAP SE or an SAP affiliate company.
 * All rights reserved.
 * Please see http://www.sap.com/corporate-en/legal/copyright/index.epx for additional trademark information and
 * notices.
 */
package com.sap.cloud.yaas.servicesdk.apiconsole.utils;

import com.sap.cloud.yaas.servicesdk.apiconsole.model.AppInfo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Locale;
import java.util.Properties;
import java.util.Set;
import java.util.jar.Manifest;

import javax.servlet.ServletContext;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * This class provide functionality to read application info from pom.properties file.
 */
public class AppInfoReader
{
	/**
	 * Environment variable key identifying the deployed application name.
	 */
	private static final String APPLICATION_NAME = "APP_NAME";
	/**
	 * Environment variable key identifying the deployed application version.
	 */
	private static final String APPLICATION_VERSION = "APP_VERSION";
	/**
	 * Environment variable key identifying the deployed application build time.
	 */
	private static final String BUILD_TIME = "BUILD_TIME";

	private static final Logger LOG = LoggerFactory.getLogger(AppInfoReader.class);

	/**
	 * Line number for line from pom.properties containing built time.
	 */
	private static final int BUILD_TIME_LINE_NUMBER = 2;

	/**
	 * Read and return information about application from pom.properties files.
	 *
	 * @param context - context.
	 * @return Information about application from pom.properties files
	 */
	public AppInfo getAppVersion(final ServletContext context)
	{
		if (context == null)
		{
			return null; // no context - probably test environment
		}

		AppInfo result = resolveInfoFromEnvVariables();
		if (result == null)
		{
			result = resolveInfoFromManifest(context);
		}
		if (result == null)
		{
			result = resolveInfoFromPomProperties(context);
		}
		return result;
	}

	private AppInfo resolveInfoFromEnvVariables()
	{
		final String appName = getEnvVariable(APPLICATION_NAME);
		final String appVersion = getEnvVariable(APPLICATION_VERSION);
		final String buildTime = getEnvVariable(BUILD_TIME);
		if (appName == null || appVersion == null)
		{
			return null;
		}
		final AppInfo result = new AppInfo();
		result.setArtifactId(appName);
		result.setVersion(appVersion);
		result.setBuildTime(buildTime);
		return result;
	}

	private AppInfo resolveInfoFromManifest(final ServletContext context)
	{
		try (final InputStream manifestStream = context.getResourceAsStream("/META-INF/MANIFEST.MF");)
		{
			if (manifestStream != null)
			{
				final AppInfo appVersion = new AppInfo();
				final Manifest manifest = new Manifest(manifestStream);
				appVersion.setArtifactId(manifest.getMainAttributes().getValue("Implementation-Title"));
				appVersion.setGroupId(manifest.getMainAttributes().getValue("Implementation-Vendor-Id"));
				appVersion.setVersion(manifest.getMainAttributes().getValue("Implementation-Version"));
				appVersion.setBuildTime(manifest.getMainAttributes().getValue("Build-Time"));
				return appVersion;
			}
			else
			{
				LOG.warn("Manifest file not found at /META-INF/MANIFEST.MF");
			}
		}
		catch (final IOException e)
		{
			LOG.warn("Error reading manifest file", e);
		}
		return null;
	}

	private AppInfo resolveInfoFromPomProperties(final ServletContext context)
	{
		final String pomFilePath = findPomProperties(context, "/META-INF/maven");

		if (pomFilePath == null)
		{
			return null;
		}

		final AppInfo appVersion = new AppInfo();

		try (final InputStream is = context.getResourceAsStream(pomFilePath))
		{
			if (is == null)
			{
				throw new IOException("File not found.");
			}
			final Properties properties = new Properties();
			properties.load(is);
			appVersion.setArtifactId(properties.getProperty("artifactId"));
			appVersion.setGroupId(properties.getProperty("groupId"));
			appVersion.setVersion(properties.getProperty("version"));
		}
		catch (final IOException ex)
		{
			LOG.error("Error reading pom.properties file", ex);
			return null;
		}

		try (BufferedReader in = new BufferedReader(new InputStreamReader(context.getResourceAsStream(pomFilePath),
				StandardCharsets.UTF_8)))
		{
			String line;
			int lineNumber = 0;
			while ((line = in.readLine()) != null)
			{
				lineNumber = lineNumber + 1;
				if (lineNumber == BUILD_TIME_LINE_NUMBER)
				{
					appVersion.setBuildTime(line.substring("#".length()));
					break;
				}
			}
		}
		catch (final IOException ex)
		{
			LOG.error("Error reading pom.properties file", ex);
		}
		return appVersion;
	}

	private String findPomProperties(final ServletContext context, final String root)
	{
		if (root.toLowerCase(Locale.getDefault()).endsWith("pom.properties"))
		{
			return root;
		}
		final Set paths = context.getResourcePaths(root);
		if (paths != null)
		{
			for (final String path : paths)
			{
				final String pomPath = findPomProperties(context, path);
				if (pomPath != null)
				{
					return pomPath;
				}
			}
		}
		return null;
	}

	/**
	 * Returns environment variable with given name. If a system property with same name
	 * is set, it will return the system property.
	 *
	 * @param varName the name of system property or environment variable to retrieve
	 * @return the value of the system property or environment variable
	 */
	private String getEnvVariable(final String varName)
	{
		final String systemProperty = System.getProperty(varName);
		if (systemProperty == null)
		{
			return System.getenv(varName);
		}
		else
		{
			return systemProperty;
		}
	}
}