Web server log (Squid) monitoring with Netdata

Squid is a caching and forwarding HTTP web proxy.

This module parses Squid access logs.

Charts

Module produces following charts:

• Total Requests in requests/s
• Excluded Requests in requests/s
• Requests By Type in requests/s
• Responses By HTTP Status Code Class in responses/s
• Responses By HTTP Status Code in responses/s
• Bandwidth in kilobits/s
• Response Time in milliseconds/s
• Unique Clients in clients/s
• Requests By Cache Result Code in requests/s
• Requests By Cache Result Delivery Transport Tag in requests/s
• Requests By Cache Result Handling Tag in requests/s
• Requests By Cache Result Produced Object Tag in requests/s
• Requests By Cache Result Load Source Tag in requests/s
• Requests By Cache Result Errors Tag in requests/s
• Requests By HTTP Method in requests/s
• Requests By MIME Type in requests/s
• Requests By Hierarchy Code in requests/s
• Forwarded Requests By Server Address in requests/s

Log Parsers

Squidlog supports 3 log parsers:

• CSV
• LTSV
• RegExp

RegExp is the slowest among them but it is very likely you will need to use it if your log format is not default.

Known Fields

These are Squid log format codes.

Squidlog is aware how to parse and interpret following codes:

field	squid format code	description
resp_time	%tr	Response time (milliseconds).
client_address	%>a	Client source IP address.
client_address	%>A	Client FQDN.
cache_code	%Ss	Squid request status (TCP_MISS etc).
http_code	%>Hs	The HTTP response status code from Content Gateway to client.
resp_size	%<st	Total size of reply sent to client (after adaptation).
req_method	%rm	Request method (GET/POST etc).
hier_code	%Sh	Squid hierarchy status (DEFAULT_PARENT etc).
server_address	%<a	Server IP address of the last server or peer connection.
server_address	%<A	Server FQDN or peer name.
mime_type	%mt	MIME content type.

In addition, to make Squid native log format csv parsable, squidlog understands these groups of codes:

field	squid format code	description
result_code	%Ss/%>Hs	Cache code and http code.
hierarchy	%Sh/%<a	Hierarchy code and server address.

Custom Log Format

Custom log format is easy. Use known fields to construct your log format.

• If using CSV parser

Note: can be used only if all known squid format codes are separated by csv delimiter. For example, if you have %Ss:%Sh, csv parser cant extract %Ss and %Sh from it and you need to use RegExp parser.

Copy your current log format. Replace all known squid format codes with corresponding known fields. Replaces others with "-".

jobs:

- name: squid_log_custom_csv_exampla

path: /var/log/squid/access.log

log_type: csv

csv_config:

format: '- resp_time client_address result_code resp_size req_method - - hierarchy mime_type'

• If using LTSV parser

Provide fields mapping. You need to map your label names to known fields.

- name: squid_log_custom_ltsv_exampla

path: /var/log/squid/access.log

log_type: ltsv

ltsv_config:

mapping:

label1: resp_time

label2: client_address

...

• If using RegExp parser

Use pattern with subexpressions names. These names should be known by squidlog. We recommend to use https://regex101.com/ to test your regular expression.

jobs:

- name: squid_log_custom_regexp_exampla

path: /var/log/squid/access.log

log_type: regexp

regexp_config:

format: '^[0-9.]+\s+(?P<resp_time>[0-9]+) (?P<client_address>[\da-f.:]+) (?P<cache_code>[A-Z_]+)\/(?P<http_code>[0-9]+) (?P<resp_size>[0-9]+) (?P<req_method>[A-Z]+) [^ ]+ [^ ]+ (?P<hier_code>[A-Z_]+)\/[\da-z.:-]+ (?P<mime_type>[A-Za-z-]+)'

Configuration

Edit the go.d/squidlog.conf configuration file using edit-config from the Netdata config directory, which is typically at /etc/netdata.

cd /etc/netdata # Replace this path with your Netdata config directory

sudo ./edit-config go.d/squidlog.conf

This module needs only path to log file if you use native log format. If you use custom log format you need to set it manually.

jobs:

- name: squid

path: /var/log/squid/access.log

For all available options, please see the module configuration file.

Troubleshooting

To troubleshoot issues with the squid_log collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

First, navigate to your plugins directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the setting plugins directory. Once you're in the plugin's directory, switch to the netdata user.

cd /usr/libexec/netdata/plugins.d/

sudo -u netdata -s

You can now run the go.d.plugin to debug the collector:

./go.d.plugin -d -m squid_log