metric_aggregation_enabled and metric_aggregation settings do not work in Loki 3.1.2

[hoonyworld]

Describe the bug

In Loki 3.1.2, the metric_aggregation_enabled and metric_aggregation configuration options are not working as expected. When these settings are included in the cmd/loki/loki-local-config.yaml file and Loki is started using docker-compose, the following error occurs:

failed parsing config: /etc/loki/local-config.yaml: yaml: unmarshal errors:
  line 32: field metric_aggregation_enabled not found in type validation.plain
  line 48: field metric_aggregation not found in type pattern.Config. Use `-config.expand-env=true` flag if you want to expand environment variables in your config file

To Reproduce
Steps to reproduce the behavior:

1. Use Loki 3.1.2(latest) version.
2. Include the following configuration in loki-local-config.yaml

limits_config:
  metric_aggregation_enabled: true

pattern_ingester:
  enabled: true
  metric_aggregation:
    loki_address: localhost:3100

3. Start Loki with docker-compose.
4. Observe the following error message

failed parsing config: /etc/loki/local-config.yaml: yaml: unmarshal errors:
  line 32: field metric_aggregation_enabled not found in type validation.plain
  line 48: field metric_aggregation not found in type pattern.Config. Use `-config.expand-env=true` flag if you want to expand environment variables in your config file

Expected behavior
I expected that enabling metric_aggregation_enabled: true would activate metric aggregation functionality in Loki. Additionally, the metric_aggregation configuration under pattern_ingester should work as intended for log aggregation.

Environment:

• Infrastructure: Ubuntu 24, Docker
• Deployment tool: Docker Compose

Screenshots, Promtail config, or terminal output

• Here is the relevant section of the loki-local-config.yaml file:

auth_enabled: false

server:
  http_listen_port: 3100
  log_level: info

common:
  instance_addr: 127.0.0.1
  path_prefix: /var/loki
  storage:
    filesystem:
      chunks_directory: /var/loki/chunks
      rules_directory: /var/loki/rules
  replication_factor: 1
  ring:
    kvstore:
      store: inmemory

query_range:
  results_cache:
    cache:
      embedded_cache:
        enabled: true
        max_size_mb: 100

limits_config:
  metric_aggregation_enabled: true

schema_config:
  configs:
    - from: 2020-10-24
      store: tsdb
      object_store: filesystem
      schema: v13
      index:
        prefix: index_
        period: 24h

pattern_ingester:
  enabled: true
  metric_aggregation:
    loki_address: localhost:3100

ruler:
  alertmanager_url: http://localhost:9093

frontend:
  encoding: protobuf

• The following error appears when Loki attempts to start

[chaudum]

@hoonyworld You are using the example config for a wrong Loki version. You can find the loki-local-config.yaml for 3.1.x here: https://github.com/grafana/loki/blob/release-3.1.x/cmd/loki/loki-local-config.yaml

[danielo515]

This same problem happens with loki 3.3.0, but in the opposite direction.

This is what the default example file here has:

pattern_ingester:
  enabled: true
  metric_aggregation:
    enabled: true
    loki_address: localhost:3100

And this is the output from loki 3.3.0:

loki, version 3.3.0 (branch: , revision: unknown)
  build user:       buildozer@build-edge-x86_64
  build date:       2024-12-01T16:51:48Z
  go version:       go1.23.3
  platform:         linux/amd64
  tags:             netgo
grafana:~# loki -config.file=/etc/loki/loki-local-config.yaml -config.expand-env=true
failed parsing config: /etc/loki/loki-local-config.yaml: yaml: unmarshal errors:
  line 41: field enabled not found in type aggregation.Config