--- title: Reader weight: 2 menu: docs: parent: "vmanomaly-components" weight: 2 aliases: - /anomaly-detection/components/reader.html --- VictoriaMetrics Anomaly Detection (`vmanomaly`) primarily uses [VmReader](#vm-reader) to ingest data. This reader focuses on fetching time-series data directly from VictoriaMetrics with the help of powerful [MetricsQL](https://docs.victoriametrics.com/metricsql/) expressions for aggregating, filtering and grouping your data, ensuring seamless integration and efficient data handling. Future updates will introduce additional readers, expanding the range of data sources `vmanomaly` can work with. ## VM reader > **Note**: Starting from [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130) there is backward-compatible change of [`queries`](https://docs.victoriametrics.com/anomaly-detection/components/reader?highlight=queries#vm-reader) arg of [VmReader](#vm-reader). New format allows to specify per-query parameters, like `step` to reduce amount of data read from VictoriaMetrics TSDB and to allow config flexibility. Please see [per-query parameters](#per-query-parameters) section for the details. Old format like ```yaml # other config sections ... reader: class: 'vm' datasource_url: 'http://localhost:8428' # source victoriametrics/prometheus sampling_period: "10s" # set it <= min(infer_every) in schedulers section queries: # old format {query_alias: query_expr}, prior to 1.13, will be converted to a new format automatically vmb: 'avg(vm_blocks)' ``` will be converted to a new one with a warning raised in logs: ```yaml # other config sections ... reader: class: 'vm' datasource_url: 'http://localhost:8428' # source victoriametrics/prometheus sampling_period: '10s' queries: # old format {query_alias: query_expr}, prior to 1.13, will be converted to a new format automatically vmb: expr: 'avg(vm_blocks)' # initial MetricsQL expression step: '10s' # individual step for this query, will be filled with `sampling_period` from the root level data_range: ['-inf', 'inf'] # by default, no constraints applied on data range # new query-level arguments will be added in backward-compatible way in future releases ``` ### Per-query parameters Starting from [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130) there is change of [`queries`](https://docs.victoriametrics.com/anomaly-detection/components/reader?highlight=queries#vm-reader) arg format. Now each query alias supports the next (sub)fields: - `expr` (string): MetricsQL/PromQL expression that defines an input for VmReader. As accepted by `/query_range?query=%s`. i.e. `avg(vm_blocks)` - `step` (string): query-level frequency of the points returned, i.e. `30s`. Will be converted to `/query_range?step=%s` param (in seconds). Useful to optimize total amount of data read from VictoriaMetrics, where different queries may have **different frequencies for different [machine learning models](https://docs.victoriametrics.com/anomaly-detection/components/models)** to run on. > **Note**: if not set explicitly (or if older config style prior to [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130)) is used, then it is set to reader-level `sampling_period` arg. > **Note**: having **different** individual `step` args for queries (i.e. `30s` for `q1` and `2m` for `q2`) is not yet supported for [multivariate model](https://docs.victoriametrics.com/anomaly-detection/components/models/#multivariate-models) if you want to run it on several queries simultaneously (i.e. setting [`queries`](https://docs.victoriametrics.com/anomaly-detection/components/models/#queries) arg of a model to [`q1`, `q2`]). - `data_range` (list[float | string]): Introduced in [v1.15.1](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1151), it allows defining **valid** data ranges for input per individual query in `queries`, resulting in: - **High anomaly scores** (>1) when the *data falls outside the expected range*, indicating a data constraint violation. - **Lowest anomaly scores** (=0) when the *model's predictions (`yhat`) fall outside the expected range*, meaning uncertain predictions. ### Per-query config example ```yaml reader: class: 'vm' sampling_period: '1m' # other reader params ... queries: ingestion_rate: expr: 'sum(rate(vm_rows_inserted_total[5m])) by (type) > 0' step: '2m' # overrides global `sampling_period` of 1m data_range: [10, 'inf'] # meaning only positive values > 10 are expected, i.e. a value `y` < 10 will trigger anomaly score > 1 ``` ### Config parameters
Parameter Example Description
`class` `reader.vm.VmReader` (or `vm` starting from [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130)) Name of the class needed to enable reading from VictoriaMetrics or Prometheus. VmReader is the default option, if not specified.
`queries` See [per-query config example](#per-query-config-example) above See [per-query config section](#per-query-parameters) above
`datasource_url` `http://localhost:8481/` Datasource URL address
`tenant_id` `0:0` For VictoriaMetrics Cluster version only, tenants are identified by accountID or accountID:projectID. See VictoriaMetrics Cluster [multitenancy docs](https://docs.victoriametrics.com/cluster-victoriametrics/#multitenancy)
`sampling_period` `1h` Frequency of the points returned. Will be converted to `/query_range?step=%s` param (in seconds). **Required** since [v1.9.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v190).
`query_range_path` `/api/v1/query_range` Performs PromQL/MetricsQL range query
`health_path` `health` Absolute or relative URL address where to check availability of the datasource.
`user` `USERNAME` BasicAuth username
`password` `PASSWORD` BasicAuth password
`timeout` `30s` Timeout for the requests, passed as a string
`verify_tls` `false` Allows disabling TLS verification of the remote certificate.
`bearer_token` `token` Token is passed in the standard format with header: `Authorization: bearer {token}`
`extra_filters` `[]` List of strings with series selector. See: [Prometheus querying API enhancements](https://docs.victoriametrics.com/##prometheus-querying-api-enhancements)
`query_from_last_seen_timestamp` `False` If True, then query will be performed from the last seen timestamp for a given series. If False, then query will be performed from the start timestamp, based on a schedule period. Defaults to `False`. Useful for `infer` stages in case there were skipped `infer` calls prior to given.
`latency_offset` `1ms` Introduced in [v1.15.1](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1151), it allows overriding the default `-search.latencyOffset` [flag of VictoriaMetrics](https://docs.victoriametrics.com/?highlight=search.latencyOffset#list-of-command-line-flags) (30s). The default value is set to 1ms, which should help in cases where `sampling_frequency` is low (10-60s) and `sampling_frequency` equals `infer_every` in the [PeriodicScheduler](https://docs.victoriametrics.com/anomaly-detection/components/scheduler/?highlight=infer_every#periodic-scheduler). This prevents users from receiving `service - WARNING - [Scheduler [scheduler_alias]] No data available for inference.` warnings in logs and allows for consecutive `infer` calls without gaps. To restore the old behavior, set it equal to your `-search.latencyOffset` [flag value]((https://docs.victoriametrics.com/?highlight=search.latencyOffset#list-of-command-line-flags)).
Config file example: ```yaml reader: class: "vm" # or "reader.vm.VmReader" until v1.13.0 datasource_url: "https://play.victoriametrics.com/" tenant_id: "0:0" queries: ingestion_rate: expr: 'sum(rate(vm_rows_inserted_total[5m])) by (type) > 0' step: '1m' # can override global `sampling_period` on per-query level data_range: [0, 'inf'] sampling_period: '1m' query_from_last_seen_timestamp: True # false by default latency_offset: '1ms' ``` ### Healthcheck metrics `VmReader` exposes [several healthchecks metrics](https://docs.victoriametrics.com/anomaly-detection/components/monitoring/#reader-behaviour-metrics).