clear table

Remove one or more entries from a stick table.

Description Jump to heading #

With no arguments, clear table removes all records from a stick table.

You can also select specific records to remove. Specify either the key of the record to remove or an expression that matches a record’s counters.

Examples Jump to heading #

Consider this real-world example that uses a stick-table to track clients that exceed a rate limit and bans clients that exceed the limit three times:

haproxy
frontend fe_main
  bind :80
  # define stick table
  stick-table  type ip  size 100k  expire 24h  store http_req_rate(5s),gpc0,gpt0
  # begin tracking requests where the key in the table
  # is the client's source IP
  http-request track-sc0 src
  # has the client exceeded 20 requests in 5 seconds?
  acl exceeds_rate_limit sc_http_req_rate(0) gt 20
  # flag them if they exceeded the limit
  http-request sc-set-gpt0(0) 1 if exceeds_rate_limit
  # if they exceeded the limit 3 times, mark them as a known speeder
  acl known_speeder sc_get_gpc0(0) ge 3
  # deny all clients that exceed the limit or are known speeders
  http-request deny deny_status 429 if exceeds_rate_limit || known_speeder
  # count each time they exceed the limit if they were flagged
  acl issue_speeding_ticket sc_get_gpt0(0) eq 1
  http-request sc-inc-gpc0(0) if issue_speeding_ticket
  # reset the flag
  http-request sc-set-gpt0(0) 0
  default_backend be_servers

haproxy
frontend fe_main
  bind :80
  # define stick table
  stick-table  type ip  size 100k  expire 24h  store http_req_rate(5s),gpc0,gpt0
  # begin tracking requests where the key in the table
  # is the client's source IP
  http-request track-sc0 src
  # has the client exceeded 20 requests in 5 seconds?
  acl exceeds_rate_limit sc_http_req_rate(0) gt 20
  # flag them if they exceeded the limit
  http-request sc-set-gpt0(0) 1 if exceeds_rate_limit
  # if they exceeded the limit 3 times, mark them as a known speeder
  acl known_speeder sc_get_gpc0(0) ge 3
  # deny all clients that exceed the limit or are known speeders
  http-request deny deny_status 429 if exceeds_rate_limit || known_speeder
  # count each time they exceed the limit if they were flagged
  acl issue_speeding_ticket sc_get_gpt0(0) eq 1
  http-request sc-inc-gpc0(0) if issue_speeding_ticket
  # reset the flag
  http-request sc-set-gpt0(0) 0
  default_backend be_servers

First, use show table to lists records in the table fe_main:

nix
echo "show table fe_main" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

nix
echo "show table fe_main" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

output
text
# table: fe_main, type: ip, size:102400, used:1
0x5641b364f7e8: key=192.168.50.19 use=0 exp=86398242 gpt0=0 gpc0=3 http_req_rate(5000)=5
0x5641b364f7e8: key=192.168.50.24 use=0 exp=86398220 gpt0=0 gpc0=1 http_req_rate(5000)=5
0x5641b364f7e8: key=192.168.50.30 use=0 exp=86398250 gpt0=0 gpc0=1 http_req_rate(5000)=5 

output
text
# table: fe_main, type: ip, size:102400, used:1
0x5641b364f7e8: key=192.168.50.19 use=0 exp=86398242 gpt0=0 gpc0=3 http_req_rate(5000)=5
0x5641b364f7e8: key=192.168.50.24 use=0 exp=86398220 gpt0=0 gpc0=1 http_req_rate(5000)=5
0x5641b364f7e8: key=192.168.50.30 use=0 exp=86398250 gpt0=0 gpc0=1 http_req_rate(5000)=5 

The key is the client’s IP address, and there are three counters tracked: gpt0, gpc0, and http_req_rate(5000).

Use clear table with no arguments to remove all records:

nix
echo "clear table fe_main" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

nix
echo "clear table fe_main" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

Set the key parameter to remove only the record that has a key with the given value. Here, we remove the record with the key 192.168.50.19:

nix
echo "clear table fe_main key 192.168.50.19" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

nix
echo "clear table fe_main key 192.168.50.19" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

You can also select records to remove using a filter expression. Prefix the counter you want to filter on with data. Here, we remove records that have a gpc0 counter set to 1:

nix
echo "clear table fe_main data.gpc0 eq 1" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

nix
echo "clear table fe_main data.gpc0 eq 1" | \
  sudo socat stdio tcp4-connect:127.0.0.1:9999

Use any of the following comparison operators:

• eq : true if the counter equals the value
• ge : true if the counter is greater than or equal to the value
• gt : true if the counter is greater than the value
• le : true if the counter is less than or equal to the value
• lt : true if the counter is less than the value

See also Jump to heading #

• set table
• show table