Loki Helm chart can't be naturally used as a dependency

[okashansky-mdsol]

Describe the bug If you create a parent chart that includes the loki chart as a dependency, its processing with 'helm template' fails. To fix the error, please remove '$' symbol from here: https://github.com/grafana/loki/blob/f06eabbf0e2c3db3ec899c224d6c947c5edd7d6a/production/helm/loki/templates/_helpers.tpl#L228

To Reproduce Steps to reproduce the behavior: Create a chart like

apiVersion: v2
name: my-loki
description: A Helm chart for loki

appVersion: "1.0.0"
version: "6.6.3"

dependencies:
  - name: loki
    version: 6.6.3
    repository: https://grafana.github.io/helm-charts

and try to 'helm template' it.

Temporary workaround Put the storage.bucketNames.* to the parent chart's parameters, using a values file like

loki:
  storage:
    bucketNames:
      chunks: loki-migration
      ruler: loki-migration
      admin: loki-migration
  loki:
    # other parameters here
...

Expected behavior Compilation does not fail.

Environment: Sonoma, Ubuntu, WSL2

[razvanphp]

Maybe related, but those config values are also not properly validated, if one omits the storage/bucketNames gets this ugly error:

Helm install failed for release ix-grafana/ix-grafana-loki with chart loki@6.6.3: template: loki/templates/write/statefulset-write.yaml:50:28: executing "loki/templates/write/statefulset-write.yaml" at <include (print .Template.BasePath "/config.yaml") .>: error calling include: template: loki/templates/config.yaml:19:7: executing "loki/templates/config.yaml" at <include "loki.calculatedConfig" .>: error calling include: template: loki/templates/_helpers.tpl:537:24: executing "loki.calculatedConfig" at <tpl .Values.loki.config .>: error calling tpl: error during tpl function execution for "{{- if .Values.enterprise.enabled}}\n{{- tpl .Values.enterprise.config . }}\n{{- else }}\nauth_enabled: {{ .Values.loki.auth_enabled }}\n{{- end }}\n\n{{- with .Values.loki.server }}\nserver:\n {{- toYaml . | nindent 2}}\n{{- end}}\n\npattern_ingester:\n enabled: {{ .Values.loki.pattern_ingester.enabled }}\n\nmemberlist:\n{{- if .Values.loki.memberlistConfig }}\n {{- toYaml .Values.loki.memberlistConfig | nindent 2 }}\n{{- else }}\n{{- if .Values.loki.extraMemberlistConfig}}\n{{- toYaml .Values.loki.extraMemberlistConfig | nindent 2}}\n{{- end }}\n join_members:\n - {{ include \"loki.memberlist\" . }}\n {{- with .Values.migrate.fromDistributed }}\n {{- if .enabled }}\n - {{ .memberlistService }}\n {{- end }}\n {{- end }}\n{{- end }}\n\n{{- with .Values.loki.ingester }}\ningester:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- if .Values.loki.commonConfig}}\ncommon:\n{{- toYaml .Values.loki.commonConfig | nindent 2}}\n storage:\n {{- include \"loki.commonStorageConfig\" . | nindent 4}}\n{{- end}}\n\n{{- with .Values.loki.limits_config }}\nlimits_config:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\nruntime_config:\n file: /etc/loki/runtime-config/runtime-config.yaml\n\n{{- with .Values.chunksCache }}\n{{- if .enabled }}\nchunk_store_config:\n chunk_cache_config:\n default_validity: {{ .defaultValidity }}\n background:\n writeback_goroutines: {{ .writebackParallelism }}\n writeback_buffer: {{ .writebackBuffer }}\n writeback_size_limit: {{ .writebackSizeLimit }}\n memcached:\n batch_size: {{ .batchSize }}\n parallelism: {{ .parallelism }}\n memcached_client:\n addresses: dnssrvnoa+_memcached-client._tcp.{{ template \"loki.fullname\" $ }}-chunks-cache.{{ $.Release.Namespace }}.svc\n consistent_hash: true\n timeout: {{ .timeout }}\n max_idle_conns: 72\n{{- end }}\n{{- end }}\n\n{{- if .Values.loki.schemaConfig }}\nschema_config:\n{{- toYaml .Values.loki.schemaConfig | nindent 2}}\n{{- end }}\n\n{{- if .Values.loki.useTestSchema }}\nschema_config:\n{{- toYaml .Values.loki.testSchemaConfig | nindent 2}}\n{{- end }}\n\n{{ include \"loki.rulerConfig\" . }}\n\n{{- if or .Values.tableManager.retention_deletes_enabled .Values.tableManager.retention_period }}\ntable_manager:\n retention_deletes_enabled: {{ .Values.tableManager.retention_deletes_enabled }}\n retention_period: {{ .Values.tableManager.retention_period }}\n{{- end }}\n\nquery_range:\n align_queries_with_step: true\n {{- with .Values.loki.query_range }}\n {{- tpl (. | toYaml) $ | nindent 2 }}\n {{- end }}\n {{- if .Values.resultsCache.enabled }}\n {{- with .Values.resultsCache }}\n cache_results: true\n results_cache:\n cache:\n default_validity: {{ .defaultValidity }}\n background:\n writeback_goroutines: {{ .writebackParallelism }}\n writeback_buffer: {{ .writebackBuffer }}\n writeback_size_limit: {{ .writebackSizeLimit }}\n memcached_client:\n consistent_hash: true\n addresses: dnssrvnoa+_memcached-client._tcp.{{ template \"loki.fullname\" $ }}-results-cache.{{ $.Release.Namespace }}.svc\n timeout: {{ .timeout }}\n update_interval: 1m\n {{- end }}\n {{- end }}\n\n{{- with .Values.loki.storage_config }}\nstorage_config:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.query_scheduler }}\nquery_scheduler:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.compactor }}\ncompactor:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.analytics }}\nanalytics:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.querier }}\nquerier:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.index_gateway }}\nindex_gateway:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.frontend }}\nfrontend:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.frontend_worker }}\nfrontend_worker:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\n{{- with .Values.loki.distributor }}\ndistributor:\n {{- tpl (. | toYaml) $ | nindent 4 }}\n{{- end }}\n\ntracing:\n enabled: {{ .Values.loki.tracing.enabled }}\n": template: loki/templates/write/statefulset-write.yaml:40:6: executing "loki/templates/write/statefulset-write.yaml" at <include "loki.commonStorageConfig" .>: error calling include: template: loki/templates/_helpers.tpl:228:19: executing "loki.commonStorageConfig" at <$.Values.loki.storage.bucketNames.chunks>: nil pointer evaluating interface {}.chunks

instead of something like:

Helm install failed for release ix-grafana/ix-grafana-loki with chart loki@6.6.3: execution error at (loki/templates/validate.yaml:40:4): You must provide a schema_config for Loki, one is not provided as this will be individual for every Loki cluster. See https://grafana.com/docs/loki/latest/operations/storage/schema/ for schema information. For quick testing (with no persistence) add --set loki.useTestSchema=true

[horihel]

There's an interesting interaction here. I can make my loki chart render easily by specifying the values for the subchart

assuming i have loki in my Chart.yaml as a dependency "loki", config would be

loki:
  loki:
    storage:
      type: s3
      bucketNames:
        chunks: "bla"
    schemaConfig: <add schemaconfig here>

this does render with "helm template", but interestingly, it still fails when calling "helm lint --with-subcharts", also with

error calling include: template: loki/templates/_helpers.tpl:228:19: executing "loki.commonStorageConfig" at <$.Values.loki.storage.bucketNames.chunks>: nil pointer evaluating interface {}.chunks

which is interesting, because (AFAIK), lint should use the same variables, but finds a nil pointer instead.

additionally, lint even falls over this same error if you specify loki.loki.storage.type=filesystem, which should completely ignore the codepath... but it doesn't.

i'm close to suspecting there's a bug in helm...

Update: Please ignore this comment - helm lint failure is indeed a helm bug and my comment is only related as in the error message is the same.