java - Micronaut 和 Java Mail API

Question

我们正在尝试将单体应用的一部分迁移到微服务，因此我们决定使用 micronaut。我们现在正在提取一个电子邮件服务，该服务提供一些输入将呈现电子邮件并与 SMTP 服务器交谈以发送它们。

为此，我们使用 Java Mail，当我们尝试创建 GraalVM docker 镜像时，它似乎有一些问题。有没有人设法做到这一点，或者根本不可能让它发挥作用？

一些附加信息:

Docker 文件:

FROM oracle/graalvm-ce:19.2.0 as graalvm
COPY . /home/app/email-service
WORKDIR /home/app/email-service
RUN gu install native-image
RUN native-image --no-server -cp build/libs/email-service-*.jar

FROM frolvlad/alpine-glibc
EXPOSE 8080
COPY --from=graalvm /home/app/email-service .
ENTRYPOINT ["./email-service"]

原生图像.properties:

JDBC 驱动程序、redis、kafka 和 thymeleaf 有一些其他“惰性”初始化。

Args = --initialize-at-run-time=io.micronaut.views.thymeleaf.ThymeleafFactory \
       --initialize-at-run-time=io.micronaut.views.thymeleaf.ThymeleafViewsRenderer \
       --initialize-at-run-time=io.micronaut.views.velocity.VelocityViewsRenderer \
       --initialize-at-run-time=io.micronaut.configuration.lettuce.session.$RedisHttpSessionConfigurationDefinition \
       --initialize-at-run-time=io.micronaut.configuration.kafka.embedded.KafkaEmbedded \
       --initialize-at-run-time=oracle.jdbc.driver.OracleDriver \
       --initialize-at-run-time=java.sql.DriverManager \
       --initialize-at-run-time=org.hibernate.jpa.HibernatePersistenceProvider \
       --initialize-at-run-time=com.sun.mail.util.MailLogger \
       -H:IncludeResources=logback.xml|application.yml \
       -H:Name=email-service \
       -H:Class=com.acme.MySuperDuperApplication

Micronaut 版本:1.2.0
Java 邮件版本:1.6.2 (com.sun.mail:javax.mail:1.6.2)

原生图像编译错误:

Warning: Aborting stand-alone image build. com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: No instances of com.sun.mail.util.MailLogger are allowed in the image heap as this class should be initialized at image runtime. To see how this object got instantiated use -H:+TraceClassInitialization.
Detailed message:
Trace: 
    at parsing javax.mail.internet.MailDateFormat.access$000(MailDateFormat.java:149)
Call path from entry point to javax.mail.internet.MailDateFormat.access$000(): 
    at javax.mail.internet.MailDateFormat.access$000(MailDateFormat.java:149)
    at javax.mail.internet.MailDateFormat$AbstractDateParser.parse(MailDateFormat.java:426)
    at javax.mail.internet.MailDateFormat.parse(MailDateFormat.java:251)
    at java.text.DateFormat.parse(DateFormat.java:364)
    at freemarker.core.JavaTemplateDateFormat.parse(JavaTemplateDateFormat.java:49)
    at freemarker.core.JavaTemplateDateFormat.parse(JavaTemplateDateFormat.java:33)
    at freemarker.core.BuiltInsForMultipleTypes$dateBI$DateParser.parse(BuiltInsForMultipleTypes.java:204)
    at freemarker.core.BuiltInsForMultipleTypes$dateBI$DateParser.get(BuiltInsForMultipleTypes.java:167)
    at freemarker.ext.beans.HashAdapter.get(HashAdapter.java:73)
    at freemarker.ext.beans.HashAdapter$1$1$1.getValue(HashAdapter.java:124)
    at sun.security.ssl.SSLSocketImpl$NotifyHandshakeThread.run(SSLSocketImpl.java:2687)
    at com.oracle.svm.core.thread.JavaThreads.threadStartRoutine(JavaThreads.java:460)
    at com.oracle.svm.core.posix.thread.PosixJavaThreads.pthreadStartRoutine(PosixJavaThreads.java:193)
    at com.oracle.svm.core.code.IsolateEnterStub.PosixJavaThreads_pthreadStartRoutine_e1f4a8c0039f8337338252cd8734f63a79b5e3df(generated:0)

Answer 1

不确定它是否足够，但您可以尝试在构建时初始化 com.sun.mail.util.MailLogger 传递额外的--initialize-at-build-time=com.sun.mail.util.MailLogger 作为参数

这将在运行前预加载类，这可能解决或不解决编译问题

附带说明一下，我想您可以将运行时初始化参数链接到一个逗号分隔的列表中，即

--initialize-at-runtime=io.micronaut.views.thymeleaf.ThymeleafFactory,io.micronaut.views.thymeleaf.ThumeleafViewsRenderer, ...