Parse Cloudflare Logs JSON data

After downloading your Cloudflare Logs data, you can use different tools to parse and analyze your logs.

One of those tools used to parse your JSON log data is jq.

Refer to Download jq ↗ for more information on obtaining and installing jq.

Aggregate fields

To aggregate a field appearing in the log, such as by IP address, URI, or referrer, you can use several jq commands. This is useful to identify any patterns in traffic; for example, to identify your most popular pages or to block an attack.

The following examples match on a field name and provide a count of each field instance, sorted in ascending order by count.

jq -r .ClientRequestURI logs.json | sort -n | uniq -c | sort -n | tail

2 /nginx-logo.png
2 /poweredby.png
2 /testagain
3 /favicon.ico
3 /testing
3 /testing123
6 /test
7 /testing1234
10 /cdn-cgi/nexp/dok3v=1613a3a185/cloudflare/rocket.js
54 /

jq -r .ClientRequestUserAgent logs.json | sort -n | uniq -c | sort -n | tail

1 python-requests/2.9.1
2 Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.56 Safari/537.17
4 Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.36
5 curl/7.47.2-DEV
36 Mozilla/5.0 (X11; Linux x86_64; rv:44.0) Gecko/20100101 Firefox/44.0
51 curl/7.46.0-DEV

jq -r .ClientRequestReferer logs.json | sort -n | uniq -c | sort -n | tail

2 http://example.com/testagain
3 http://example.com/testing
5 http://example.com/
5 http://example.com/testing123
7 http://example.com/testing1234
77 null

Filter fields

Another common use case involves filtering data for a specific field value and then aggregating after that. This helps answer questions like Which URLs saw the most 502 errors? For example:

jq 'select(.OriginResponseStatus == 502) | .ClientRequestURI' logs.json | sort -n | uniq -c | sort -n | tail

1 "/favicon.ico"
1 "/testing"
3 "/testing123"
6 "/test"
6 "/testing1234"
18 "/"

To find out the top IP addresses blocked by the Cloudflare WAF, use the following query:

jq -r 'select(.SecurityAction == "block") | .ClientIP' logs.json | sort -n | uniq -c | sort -n

1 127.0.0.1

Show cached requests

To retrieve your cache ratios, try the following query:

jq -r '.CacheCacheStatus' logs.json | sort -n | uniq -c | sort -n

3 hit
3 null
3 stale
4 expired
6 miss
81 unknown

Show TLS versions

To find out which TLS versions your visitors are using — for example, to decide if you can disable TLS versions that are older than 1.2 — use the following query:

jq -r '.ClientSSLProtocol' logs.json | sort -n | uniq -c | sort -n

42 none
58 TLSv1.2