Remove a field that starts with an integer

Hi Magnus,

Here is my config

filter {
if [type] == "zabbix-alerts" {
json {
source => "message"
remove_field => "message"
}
csv {
source => "trigger_hostgroup_name"
columns => [ "group1", "group2", "group3", "group4", "group5", "group6", "group7", "group8", "group9", "group10", "group11", "group12", "group13", "group14", "group15" ]
}
mutate {
gsub => [
"group2", "^ ", "",
"group3", "^ ", "",
"group4", "^ ", "",
"group5", "^ ", "",
"group6", "^ ", "",
"group7", "^ ", "",
"group8", "^ ", "",
"group9", "^ ", "",
"group10", "^ ", "",
"group11", "^ ", "",
"group12", "^ ", "",
"group13", "^ ", "",
"group14", "^ ", "",
"group15", "^ ", ""
]
}
}
}

and here is the json message that I received:

What I want is to remove the field highlight in bold which gets created every hour

{
"_index": "logstash-ptc-zabbix-alerts-2015.07.28",
"_type": "zabbix-alerts",
"_id": "AU7V5kheXErN6gNFz_bs",
"_score": null,
"_source": {
"@version": "1",
"@timestamp": "2015-07-28T18:21:55.667Z",
"host": "10.250.26.108",
"type": "zabbix-alerts",
"event_status": "PROBLEM",
"event_ip1": "10.250.15.208",
"event_time": "14:16:37",
"event_value": "1",
"event_age": "5m",
"inventory_url_b1": "",
"trigger_hostgroup_name": [
"10.250.15.0/24, 10.250.15.0/24 Windows Agent, Discovered hosts, PTC, PTC PROD, PTC PROD Windows, Windows Servers"
],
"inventory_os1": "Microsoft(R) Windows(R) Server 2003, Standard Edition",
"event_ack_status": "No",
"item_lastvalue1": "3.85",
"trigger_events_unack": "1489",
"item_id1": "35917",
"event_recovery_status": "OK",
"inventory_poc_secondary_cell1": "1",
"event_dns1": "NYVM0428",
"inventory_poc_secondary_phone_a1": "example.com",
"trigger_template_name": "UN Template OS Windows",
"item_name1": "Processor load (1 min average)",
"trigger_expression": "{NYVM0428:system.cpu.load[percpu,avg1].avg(5m)}>5",
"inventory_model1": "VMware Virtual Platform",
"action_id": "14",
"inventory_poc_secondary_name1": "1",
"problem ended": "2015.07.28 14:21:37",
"item_name_orig1": "Processor load (1 min average)",
"inventory_serialno_a1": "VMware-42 1f cb f0 57 fc d9 44-ef e2 4e 0e cd 76 94 98",
"inventory_poc_secondary_phone_b1": "1023.39 MB",
"name": "zabbix_data",
"event_conn1": "10.250.15.208",
"inventory_vendor1": "Phoenix Technologies LTD",
"event_name1": "NYVM0428",
"trigger_value": "0",
"1. 2015.07.28 14": "16:41 message sent Logstash nysv0654 "Logstash User logstash (Logstash User)"",
"event_port1": "10050",
"trigger_severity": "Average",
"trigger_name_orig": "Processor load is too high on {HOST.NAME}",
"event_host1": "NYVM0428.",
"inventory_name1": "nyvm0428",
"trigger_status": "OK",
"item_key1": "system.cpu.load[percpu,avg1]",
"trigger_events_problem_unack": "744",
"item_value1": "3.85",
"trigger_events_ack": "0",
"event_recovery_time": "14:21:37",
"inventory_poc_primary_cell1": "",
"trigger_events_problem_ack": "0",
"event_recovery_value": "0",
"item_orgi1": "system.cpu.load[percpu,avg1]",
"event_id": "4663681",
"trigger_nseverity": "3",
"event_date": "2015.07.28",
"inventory_hw_arch1": "X86-based PC",
"action_name": "Logstash Notification",
"event_recovery_id": "4664691",
"trigger_id": "16318",
"date": "2015.07.28",
"trigger_name": "Processor load is too high on NYVM0428",
"event_recovery_date": "2015.07.28",
"time": "14:21:39",
"esc_history": "Problem started: 2015.07.28 14:16:37 Age: 5m",
"message_type": "recovery",
"group1": "10.250.15.0/24",
"group2": "10.250.15.0/24 Windows Agent",
"group3": "Discovered hosts",
"group4": "PTC",
"group5": "PTC PROD",
"group6": "PTC PROD Windows",
"group7": "Windows Servers"
},
"fields": {
"@timestamp": [
1438107715667
]
},
"sort": [
1438107715667
]
}