I want to write a handler that responds to S3 put events to convert any avi files that are uploaded to mp4. I doing it in Java, in Eclipse, with the AWS toolkit plugin. For video conversion, I am using ffmpeg with ffmpeg-cli-wrapper, and I have provided a static (linux) binary of ffmpeg in the source tree.
I have found that when I upload the function, the binary gets put in /var/task
, but when I try to use the test function I’ve written, I get a “permission denied” error.
import net.bramp.ffmpeg.FFmpeg; public class LambdaFunctionHandler implements RequestHandler<S3Event, String> { private static final String FFMPEG = "/var/task/ffmpeg"; public String handleRequest(S3Event event, Context context) { try { FFmpeg ff = new FFmpeg(FFMPEG); System.out.println(ff.version()); } catch (Exception e) { e.printStackTrace(); } return "foo"; } }
And the first line of the stacktrace: java.io.IOException: Cannot run program "/var/task/ffmpeg": error=13, Permission denied
.
How do I execute this binary? I have done as others have suggested and chmod 755
the binary before uploading, but it hasn’t made a difference.
Advertisement
Answer
AWS Lambda runs on Amazon Linux. It is a known issue. Try building (with static enabled) and check if it works on Amazon Linux and upload that binary. You do not have the privileges to chmod
the files in /var/task/
. Or try this solution that works:
- Move
ffmpeg
to/tmp
chmod 755 /tmp/ffmpeg
- Call
/tmp/ffmpeg
See this discussion for more info.