search

j256 / cloudwatch-logback-appender

Appender that publishes logback log entries to AWS CloudWatch
ISC License
56 stars 37 forks source link

Check if EC2 Metadata service lookup is enabled #47

Open borisbsu opened 2 years ago

borisbsu commented 2 years ago

AWS SDK allows to disable EC2 Metadata service lookup.

When it's disabled, we will see such exception stacktrace in the logs:

com.amazonaws.AmazonClientException: EC2 Instance Metadata Service is disabled
    at com.amazonaws.internal.InstanceMetadataServiceResourceFetcher.readResource(InstanceMetadataServiceResourceFetcher.java:65)
    at com.amazonaws.internal.EC2ResourceFetcher.readResource(EC2ResourceFetcher.java:66)
    at com.amazonaws.util.EC2MetadataUtils.getItems(EC2MetadataUtils.java:407)
    at com.amazonaws.util.EC2MetadataUtils.getData(EC2MetadataUtils.java:376)
    at com.amazonaws.util.EC2MetadataUtils.getData(EC2MetadataUtils.java:372)
    at com.amazonaws.util.EC2MetadataUtils.fetchData(EC2MetadataUtils.java:426)
    at com.amazonaws.util.EC2MetadataUtils.fetchData(EC2MetadataUtils.java:420)
    at com.amazonaws.util.EC2MetadataUtils.getInstanceId(EC2MetadataUtils.java:140)
    at com.j256.cloudwatchlogbackappender.CloudWatchAppender$CloudWatchWriter.lookupInstanceName(CloudWatchAppender.java:729)
    at com.j256.cloudwatchlogbackappender.CloudWatchAppender$CloudWatchWriter.createLogsClient(CloudWatchAppender.java:639)
    at com.j256.cloudwatchlogbackappender.CloudWatchAppender$CloudWatchWriter.writeEvents(CloudWatchAppender.java:551)
    at com.j256.cloudwatchlogbackappender.CloudWatchAppender$CloudWatchWriter.run(CloudWatchAppender.java:537)
    at java.base/java.lang.Thread.run(Thread.java:834)

We can add a simple check inside our Appender to verify this case and avoid useless error in logs.