Vector does not reload vrl file

[alexeynl]

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Problem

I found in release notes that starting from v0.47.0 support for reload vrl files added.

But this does not work when config reloaded using SIGHUP (systemctl reload vector.service). In this case in vector logs i see message that config was reloaded but changes from vrl do not actually applied. I check changes by vector tap.
If i embedded this changes to yaml transform after reload i see changes using vector tap.

Configuration

sources.yaml

sources:
  test-source:
    type: vector
    address: 0.0.0.0:12345

transforms.yaml

transforms:
  test-embedded-vrl:
    type: "remap"
    source: |-
      .debug = "embedded_01"
    inputs:
      - test-source
  test-external-vrl:
    type: "remap"
    file: "/etc/vector/test/vrl/test.vrl"
    inputs:
      - test-source

/etc/vector/test/vrl/test.vrl

.debug = "external_01"

Version

0.49

Debug Output

Example Data

No response

Additional Context

No response

References

No response

[alexeynl]

It looks like external vrl file reload completely does not work as reported in release notes. Not only with sighup but using --watch-config i have the same behaviour. If i change external vrl (in file) i do not see the changes using vector tap. If i change embedded to yaml vrl i see expected changes usin vector tap.

Although vector reporting in its logs

INFO vector::topology::running: New configuration loaded successfully. 
INFO vector: Vector has reloaded. path=...

in all cases: embedded or external, manual (sighup) or automatic (--watch-config) reload method.

[pront]

Hi @alexeynl, thank you for reporting this issue.

cc-ing @nekorro who contributed #23010, in case they have thoughts.

[nekorro]

Hi,

I was unable to reproduce the problem with the provided configuration.
I tested the behavior with the --watch-config flag enabled (since #23010 was related specifically to --watch-config).
The configurations of components are successfully reloaded for both embedded and external VRL scripts.

Configuration directory

test
├── sinks.yaml
├── sources.yaml
└── transforms.yaml

sources.yaml

sources:
  test-source:
    type: demo_logs
    interval: 1
    format: json

transforms.yaml

transforms:
  test-embedded-vrl:
    type: "remap"
    source: |-
      .debug = "embedded_01"
    inputs:
      - test-source
  test-external-vrl:
    type: "remap"
    file: "/Users/vector/test/vrl/test.vrl"
    inputs:
      - test-source

/Users/vector/test/vrl/test.vrl

.debug = "external_01"

sinks.yaml

sinks:
  console:
    inputs:
      - test-embedded-vrl
      - test-external-vrl
    target: stdout
    type: console
    encoding:
      codec: json

• Run vector vector -C test -w

• Modify /Users/vector/test/vrl/test.vrl

.debug = "external_01-modified"

• test-external-vrl remap component reloaded:

• Modify test/transforms.yaml

transforms:
  test-embedded-vrl:
    type: "remap"
    source: |-
      .debug = "embedded_01-modified"
    inputs:
      - test-source
  test-external-vrl:
    type: "remap"
    file: "/Users/a.shibalov/vector/test/vrl/test.vrl"
    inputs:
      - test-source

• test-embedded-vrl remap component reloaded:

Please note that the fix in #23010 only concerns reloading when the --watch-config flag is enabled.
In that case, reload is handled via the SignalTo::ReloadComponents method, which explicitly obtains the list of components to be reloaded.
In contrast, reloads triggered by sending SIGHUP use the SignalTo::ReloadFromDisk method, which reloads from disk the configuration files (that were passed at application startup via -c or -C arguments) and does not take into account external VRL files.

[alexeynl]

I have expected that config reload works same with manual triggering using SIGHUP and automatic using --watch-config command. There is no info in docs that SIGHUP reload still has limitation and doesn't reload vrl files.
Vector logs in this case are also not clear.

Full configs set:

/opt/vector/config/issues/sources.yaml:

api:
  enabled: true
  graphql: true
  playground: false

sources:
  test-source:
    type: demo_logs
    format: json
    lines:
      - line1

transforms:
  test-embedded-vrl:
    type: "remap"
    source: |-
      .debug = "embedded_01"
    inputs:
      - test-source
  test-external-vrl:
    type: "remap"
    file: "/opt/vector/config/issue/test.vrl"
    inputs:
      - test-source

/opt/vector/config/issue/test.vrl:

.debug = "external_01"

/opt/vector/config/issue/sinks.yaml:

sinks:
  test-sink:
   type: blackhole
   inputs:
     - test-embedded-vrl
     - test-external-vrl

And steps to reproduce:

vector -C /opt/vector/config/issue/
2025-09-22T18:25:53.008057Z  INFO vector::app: Log level is enabled. level="info"
2025-09-22T18:25:53.008777Z  INFO vector::app: Loading configs. paths=["/opt/vector/config/issue"]
2025-09-22T18:25:53.211819Z  INFO vector::topology::running: Running healthchecks.
2025-09-22T18:25:53.211904Z  INFO vector: Vector has started. debug="false" version="0.49.0" arch="aarch64" revision="dc7e792 2025-08-12 13:47:08.632326804"
2025-09-22T18:25:53.211929Z  INFO vector::topology::builder: Healthcheck passed.
2025-09-22T18:25:53.212520Z  INFO vector::internal_events::api: API server running. address=127.0.0.1:8686 playground=off graphql=http://127.0.0.1:8686/graphql

vector tap output, "debug":"external_01":

vector tap test-external-vrl
2025-09-22T18:28:29.459718Z  INFO vector::app: Log level is enabled. level="info"
[tap] Pattern 'test-external-vrl' successfully matched.
{"debug":"external_01","host":"localhost","message":"{\"host\":\"34.18.179.14\",\"user-identifier\":\"BryanHorsey\",\"datetime\":\"22/Sep/2025:21:28:30\",\"method\":\"GET\",\"request\":\"/this/endpoint/prints/money\",\"protocol\":\"HTTP/1.1\",\"status\":\"401\",\"bytes\":30945,\"referer\":\"https://for.lplfinancial/wp-admin\"}","service":"vector","source_type":"demo_logs","timestamp":"2025-09-22T18:28:30.212779Z"}
{"debug":"external_01","host":"localhost","message":"{\"host\":\"72.114.110.240\",\"user-identifier\":\"jesseddy\",\"datetime\":\"22/Sep/2025:21:28:31\",\"method\":\"HEAD\",\"request\":\"/observability/metrics/production\",\"protocol\":\"HTTP/1.0\",\"status\":\"400\",\"bytes\":16933,\"referer\":\"https://make.cat/apps/deploy\"}","service":"vector","source_type":"demo_logs","timestamp":"2025-09-22T18:28:31.212003Z"}
{"debug":"external_01","host":"localhost","message":"{\"host\":\"123.240.136.60\",\"user-identifier\":\"CrucifiX\",\"datetime\":\"22/Sep/2025:21:28:32\",\"method\":\"OPTION\",\"request\":\"/wp-admin\",\"protocol\":\"HTTP/1.0\",\"status\":\"500\",\"bytes\":11671,\"referer\":\"https://some.autos/user/booperbot124\"}","service":"vector","source_type":"demo_logs","timestamp":"2025-09-22T18:28:32.212979Z"}

changing vrl:

echo '.debug = "external_02"' > /opt/vector/config/issue/test.vrl

trigger manually config reload

ps aux | grep vector                  
root 10669   0,0  0,0 410735680   1792 s003  S+    9:26     0:00.01 grep vector
root 6873   0,0  0,1 410874288  20768 s006  S+    9:25     0:00.28 vector -C /opt/vector/config/issue/

kill -SIGHUP 6873

vector outputs:

2025-09-22T18:30:25.240332Z  INFO vector::signal: Signal received. signal="SIGHUP"
2025-09-22T18:30:25.264380Z  INFO vector::topology::running: Reloading running topology with new configuration.
2025-09-22T18:30:25.268287Z  INFO vector::topology::running: Running healthchecks.
2025-09-22T18:30:25.268531Z  INFO vector::topology::running: New configuration loaded successfully.
2025-09-22T18:30:25.268960Z  INFO vector: Vector has reloaded. path=[Dir("/opt/vector/config/issue")]

vector tap shows that debug field has not changed to "debug":"external_02"

vector tap test-external-vrl
2025-09-22T18:37:50.223609Z  INFO vector::app: Log level is enabled. level="info"
[tap] Pattern 'test-external-vrl' successfully matched.
{"debug":"external_01","host":"localhost","message":"{\"host\":\"25.106.254.251\",\"user-identifier\":\"benefritz\",\"datetime\":\"22/Sep/2025:21:37:51\",\"method\":\"POST\",\"request\":\"/wp-admin\",\"protocol\":\"HTTP/1.1\",\"status\":\"304\",\"bytes\":18841,\"referer\":\"https://we.xn--qxa6a/observability/metrics/production\"}","service":"vector","source_type":"demo_logs","timestamp":"2025-09-22T18:37:51.225382Z"}
{"debug":"external_01","host":"localhost","message":"{\"host\":\"126.161.197.25\",\"user-identifier\":\"KarimMove\",\"datetime\":\"22/Sep/2025:21:37:52\",\"method\":\"OPTION\",\"request\":\"/do-not-access/needs-work\",\"protocol\":\"HTTP/2.0\",\"status\":\"404\",\"bytes\":12957,\"referer\":\"https://names.xxx/booper/bopper/mooper/mopper\"}","service":"vector","source_type":"demo_logs","timestamp":"2025-09-22T18:37:52.225613Z"}

[alexeynl]

In that case, reload is handled via the SignalTo::ReloadComponents method, which explicitly obtains the list of components to be reloaded.
In contrast, reloads triggered by sending SIGHUP use the SignalTo::ReloadFromDisk method, which reloads from disk the configuration files (that were passed at application startup via -c or -C arguments) and does not take into account external VRL files.

Is this possible to make config reload result consistent both for manual and automatic method?

[alexeynl]

Not only SIGHUP doesn't reload vrl. Here is steps how to reproduce problem when vrl is not reloaded using --watch-config

1. Make a copy of config folder from my previous comment:

cp -r /opt/vector/config/issue ./issue-orig

2. Run vector to watch /opt/vector/config/issue directory:

vector -C /opt/vector/config/issue -w

4. Change external vrl file inside issue-orig:

vi issue-orig/test.vrl

4. Replace /opt/vector/config/issue with issue-orig content:

cp -r issue-orig issue-copy;rm -rf /opt/vector/config/issue;mv issue-copy /opt/vector/config/issue

5. Check is changes applied using vector tap:

vector tap test-external-vrl

You will see that changes has actually not applied.
6. Change vrl embedded to yaml:

vi issue-orig/transforms.yaml

7. Replace /opt/vector/config/issue with issue-orig content:

cp -r issue-orig issue-copy;rm -rf /opt/vector/config/issue;mv issue-copy /opt/vector/config/issue

8. Check is changes applied using vector tap:

vector tap test-embedded-vrl

You will see that changes has applied