In OSGi + H2 environment java service HpackFieldPreEncoder can't load from org.eclipse.jetty.http

[jmcc0nn3ll]

migrated from Bugzilla #483324
status NEW severity blocker in component http2 for 9.3.x
Reported in version 9.3.6 on platform PC
Assigned to: Simone Bordet

On 2015-11-30 12:51:47 -0500, hiep lq wrote:

I setup to use http2 in OSGi project. when i run it, non error message in console.
alpn selected correct h2 as protocol, but webpage is blank.
after debug i see:
line ServiceLoader.load(HttpFieldPreEncoder.class,PreEncodedHttpField.class.getClassLoader())
class org.eclipse.jetty.http.PreEncodedHttpField
only load Http1FieldPreEncoder, can't load HpackFieldPreEncoder

so it make NPE in next step and after that java.nio.channels.ClosedChannelException

detail log at:
http://0bin.net/paste/pXcVNVcvc1-52MbS#

i don't see any error log because this log just a warning, and visible when set log level to debug.

my work-around: i merged code of org.eclipse.jetty.http and org.eclipse.jetty.http2.hpack and i get http2 in my server.

[cffan]

I had the same issue and after some digging, I found out that it is because HpackFieldPreEncoder is not included in META-INF/services. And the solution is to add
<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>

to maven-shade-plugin's config.

[hieplq]

hi @janbartel, can you help me at this issue?
i believe ServiceLoader Mediator can resolve this issue.

i try to add Capability header by osgi syntax direct to MANIFEST.MF file of org.eclipse.jetty.http and org.eclipse.jetty.http2.hpack
but not yet success, service isn't registry (i guess i do some wrong about space, case, or coma).

spi fly syntax is more easy, so i try to use it, i got success.
add below head to org.eclipse.jetty.http2.hpack
SPI-Provider: org.eclipse.jetty.http.HttpFieldPreEncoder

add bellow header to org.eclipse.jetty.http
SPI-Provider: org.eclipse.jetty.http.HttpFieldPreEncoder SPI-Consumer: java.util.ServiceLoader#load(java.lang.Class[org.eclipse.jetty.http.HttpFieldPreEncoder])

class PreEncodedHttpField change bellow line
Iterator<HttpFieldPreEncoder> iter = ServiceLoader.load(HttpFieldPreEncoder.class,PreEncodedHttpField.class.getClassLoader()).iterator();

to

Iterator<HttpFieldPreEncoder> iter = ServiceLoader.load(HttpFieldPreEncoder.class).iterator();

[joakime]

Changing the ServiceLoader to use the Thread local classloader isn't correct, it would need to use the same classloader that that interface (PreEncodedHttpField) was created from.

[joakime]

Some background on OSGi + ServiceLoader + 2 param version of .load() method

http://blog.osgi.org/2013/02/javautilserviceloader-in-osgi.html

[hieplq]

seem spi fly just work with ServiceLoader.load (Class)
i don't see any document or sample about ServiceLoader.load (Class, ClassLoad)

so we can change this line to

ClassLoader saveCl = Thread.currentThread().getContextClassLoader(); Iterator<HttpFieldPreEncoder> iter = null; try { Thread.currentThread().setContextClassLoader (PreEncodedHttpField.class.getClassLoader()); iter = ServiceLoader.load(HttpFieldPreEncoder.class).iterator(); }finally{ Thread.currentThread().setContextClassLoader(saveCl); }

[joakime]

See Issue #705 for the general solution to this class of issue.

[hieplq]

resolved on #1290