Changes are not synced to disk when modifying entries in regex map files.

[jmdelafe]

Using ?force_sync=yes when updating an entry in a map file loaded as a regex (map_reg), won't update the file on disk and it returns a 404. In-memory version (runtime) will be updated.

1. State before running the update:

$ cat maps/paths.map
^/api      apiservers
^/cart     cartservers%

$ echo "show map maps/paths.map" | socat stdio /tmp/admin.sock
0x104414cb0 ^/api apiservers
0x104414d10 ^/cart cartservers

2. Running update via Data Plane API. Notice the HTTP/1.1 404 Not Found

$ curl -v --request PUT \
  --url 'http://127.0.0.1:5555/v3/services/haproxy/runtime/maps/paths.map/entries/%5E%2Fapi?force_sync=true' \
  --header 'authorization: Basic YWRtaW46YWRtaW4=' \
  --header 'content-type: application/json' \
  --data '{
  "value": "newapiservers"
}'
*   Trying 127.0.0.1:5555...
* Connected to 127.0.0.1 (127.0.0.1) port 5555
> PUT /v3/services/haproxy/runtime/maps/paths.map/entries/%5E%2Fapi?force_sync=true HTTP/1.1
> Host: 127.0.0.1:5555
> User-Agent: curl/8.7.1
> Accept: */*
> authorization: Basic YWRtaW46YWRtaW4=
> content-type: application/json
> Content-Length: 30
>
* upload completely sent off: 30 bytes
< HTTP/1.1 404 Not Found
< Configuration-Version: 1
< Content-Type: application/json
< Vary: Origin
< Date: Fri, 19 Dec 2025 16:01:06 GMT
< Content-Length: 0
<
* Connection #0 to host 127.0.0.1 left intact

3. State after the update. notice how runtime shows the new (expected value)

$ echo "show map maps/paths.map" | socat stdio /tmp/admin.sock
0x104414cb0 ^/api newapiservers
0x104414d10 ^/cart cartservers

$ cat maps/paths.map
^/api      apiservers
^/cart     cartservers%

haproxy.cfg

global
  stats socket /tmp/admin.sock mode 777 level admin

defaults defaults
  mode http

frontend www from defaults
  bind :8888
   
  # Choose which backend depending on the URL path
  use_backend %[path,map_reg(maps/paths.map,webservers)]

  default_backend webservers

backend webservers from defaults
  http-request return status 200 content-type "text/plain" lf-string "200 OK" hdr "X-Backend" "webservers"

backend apiservers from defaults
  http-request return status 200 content-type "text/plain" lf-string "200 OK" hdr "X-Backend" "apiservers"

backend cartservers from defaults
  http-request return status 200 content-type "text/plain" lf-string "200 OK" hdr "X-Backend" "cartservers"

dataplaneapi.yml

dataplaneapi:
  socket_path: ./data-plane.sock
  host: 127.0.0.1
  port: 5555
  pid_file: ./dataplaneapi.pid
  scheme:
  - http
  - unix
  transaction:
    transaction_dir: ./storage/transactions
    backups_number: 10
    backups_dir: ./storage/backups
  resources:
    maps_dir: ./maps
    ssl_certs_dir: ./storage/ssl
    general_storage_dir: ./storage/general
    dataplane_storage_dir: ./storage/dataplane
    spoe_dir: ./storage/spoe
    spoe_transaction_dir: ./storage/transactions/spoe
  user:
  - name: admin
    insecure: true
    password: admin
haproxy:
  config_file: ./haproxy.cfg
  haproxy_bin: /opt/homebrew/bin/haproxy
  reload:
    reload_strategy: systemd
log_targets:
- log_to: stdout
  log_level: debug
  log_format: text
  log_types:
  - app
  - access

I didn't experience this when updating "regular" (or "literal) map files loaded with map directive.

[jmdelafe]

Took a closer look and I believe the issue is when getting the entry after it's updated in runtime.

$ curl --request GET \
  --url http://127.0.0.1:5555/v3/services/haproxy/runtime/maps/paths.map/entries/%5E%2Fapi \
  --header 'authorization: Basic YWRtaW46YWRtaW4='
{"code":404,"message":"/tmp/admin.sock ^/api not found"}

I don't believe the sync to disk has anything to do with the issue. It is just failing early.