Messages are not published to PubSub when using the google_cloud_storage input plugin.

[binaryninja]

Problem: Messages are not published to PubSub properly when using the google_cloud_storage input plugin. Messages are published fine when using file{} as the input source.

Steps to reproduce:
The following config file will reproduce the condition:

input {
google_cloud_storage {
interval => 30
bucket_id => "redacted"
file_matches => "log.txt"
json_key_file => "/etc/logstash/service_account_key.json"
}
}

output {
google_pubsub {
project_id => "redacted"
topic => "record_processing"
json_key_file => "/etc/logstash/service_account_key.json"
}
stdout { codec => rubydebug }
}

I can tell the contents of log.txt are being processed and I can even see the following debug message:

[DEBUG] 2020-05-12 09:24:22.741 [[main]>worker15] googlepubsub - Sending message {"message":"{"timestamp":"1586767575","name":"zzz-XXX.domain.com","type":"a","value":"123.44.67.89"}\n","@Version":"1","@timestamp":"2020-05-12T13:24:22.491Z"}