Source File
	stackdriver.go

Belonging Package
	github.com/K-Phoen/grabana/target/stackdriver

package stackdriver

import "github.com/K-Phoen/sdk"

// Option represents an option that can be used to configure a stackdriver query.
type Option func(target *Stackdriver)

const AlignmentStackdriverAuto = "stackdriver-auto"
const AlignmentGrafanaAuto = "grafana-auto"

// PreprocessorMethod defines the available pre-processing options.
type PreprocessorMethod string

const PreprocessRate = "rate"
const PreprocessDelta = "delta"

// Aligner specifies the operation that will be applied to the data points in
// each alignment period in a time series.
// See https://cloud.google.com/monitoring/api/ref_v3/rest/v3/projects.alertPolicies#Aligner
type Aligner string

const AlignNone Aligner = "ALIGN_NONE"
const AlignDelta Aligner = "ALIGN_DELTA"
const AlignRate Aligner = "ALIGN_RATE"
const AlignInterpolate Aligner = "ALIGN_INTERPOLATE"
const AlignNextOlder Aligner = "ALIGN_NEXT_OLDER"
const AlignMin Aligner = "ALIGN_MIN"
const AlignMax Aligner = "ALIGN_MAX"
const AlignMean Aligner = "ALIGN_MEAN"
const AlignCount Aligner = "ALIGN_COUNT"
const AlignSum Aligner = "ALIGN_SUM"
const AlignStdDev Aligner = "ALIGN_STDDEV"
const AlignCountTrue Aligner = "ALIGN_COUNT_TRUE"
const AlignCountFalse Aligner = "ALIGN_COUNT_FALSE"
const AlignFractionTrue Aligner = "ALIGN_FRACTION_TRUE"
const AlignPercentile99 Aligner = "ALIGN_PERCENTILE_99"
const AlignPercentile95 Aligner = "ALIGN_PERCENTILE_95"
const AlignPercentile50 Aligner = "ALIGN_PERCENTILE_50"
const AlignPercentile05 Aligner = "ALIGN_PERCENTILE_05"
const AlignPercentChange Aligner = "ALIGN_PERCENT_CHANGE"

// Reducer operation describes how to aggregate data points from multiple time
// series into a single time series, where the value of each data point in the
// resulting series is a function of all the already aligned values in the
// input time series.
// See https://cloud.google.com/monitoring/api/ref_v3/rest/v3/projects.alertPolicies#reducer
type Reducer string

const ReduceNone Reducer = "REDUCE_NONE"
const ReduceMean Reducer = "REDUCE_MEAN"
const ReduceMin Reducer = "REDUCE_MIN"
const ReduceMax Reducer = "REDUCE_MAX"
const ReduceSum Reducer = "REDUCE_SUM"
const ReduceStdDev Reducer = "REDUCE_STDDEV"
const ReduceCount Reducer = "REDUCE_COUNT"
const ReduceCountTrue Reducer = "REDUCE_COUNT_TRUE"
const ReduceCountFalse Reducer = "REDUCE_COUNT_FALSE"
const ReduceCountFractionTrue Reducer = "REDUCE_FRACTION_TRUE"
const ReducePercentile99 Reducer = "REDUCE_PERCENTILE_99"
const ReducePercentile95 Reducer = "REDUCE_PERCENTILE_95"
const ReducePercentile50 Reducer = "REDUCE_PERCENTILE_50"
const ReducePercentile05 Reducer = "REDUCE_PERCENTILE_05"

// Stackdriver represents a stackdriver query.
type Stackdriver struct {
	Builder *sdk.Target
}

// Delta represents the change in a value during a time interval.
func Delta(metricType string, options ...Option) *Stackdriver {
	return newMetric("DELTA", metricType, options...)
}

// Gauge represents an instantaneous measurement of a value.
func Gauge(metricType string, options ...Option) *Stackdriver {
	return newMetric("GAUGE", metricType, options...)
}

// Cumulative represents a value accumulated over a time interval. Cumulative
// measurements in a time series should have the same start time and
// increasing end times, until an event resets the cumulative value to zero
// and sets a new start time for the following points.
func Cumulative(metricType string, options ...Option) *Stackdriver {
	return newMetric("CUMULATIVE", metricType, options...)
}

func newMetric(metricKind string, metricType string, options ...Option) *Stackdriver {
	stackdriver := &Stackdriver{
		Builder: &sdk.Target{
			MetricType:   metricType,
			MetricKind:   metricKind,
			AlignOptions: []sdk.StackdriverAlignOptions{defaultAlignmentOpts()},
			ValueType:    "INT64",
		},
	}

	for _, opt := range append(defaults(), options...) {
		opt(stackdriver)
	}

	return stackdriver
}

func defaults() []Option {
	return []Option{
		Aggregation(ReduceMean),
		Alignment(AlignDelta, AlignmentStackdriverAuto),
	}
}

// Ref sets the reference ID for this query.
func Ref(ref string) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.RefID = ref
	}
}

// Hide the query. Grafana does not send hidden queries to the data source,
// but they can still be referenced in alerts.
func Hide() Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.Hide = true
	}
}

// Legend sets the legend format.
// See https://grafana.com/docs/grafana/latest/features/datasources/stackdriver/#alias-patterns for more
// information on allowed patterns.
func Legend(legend string) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.AliasBy = legend
	}
}

// Project defines the GCP project to use for this target.
func Project(project string) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.ProjectName = project
	}
}

// Aggregation defines how the time series will be aggregated.
func Aggregation(reducer Reducer) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.CrossSeriesReducer = string(reducer)
	}
}

// Alignment defines how the time series will be aligned.
func Alignment(aligner Aligner, alignmentPeriod string) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.AlignmentPeriod = alignmentPeriod
		stackdriver.Builder.PerSeriesAligner = string(aligner)
	}
}

// Preprocessor defines how the time series should be pre-processed.
func Preprocessor(preprocessor PreprocessorMethod) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.Preprocessor = string(preprocessor)
	}
}

// Filter allows to specify which time series will be in the results.
func Filter(filters ...FilterOption) Option {
	return func(stackdriver *Stackdriver) {
		for i, filterOpt := range filters {
			f := &filter{}
			filterOpt(f)

			if i != 0 || len(stackdriver.Builder.Filters) != 0 {
				stackdriver.Builder.Filters = append(stackdriver.Builder.Filters, "AND")
			}

			stackdriver.Builder.Filters = append(stackdriver.Builder.Filters, f.leftOperand, f.operator, f.rightOperand)
		}
	}
}

// GroupBys defines a list of fields to group the query by.
func GroupBys(groupBys ...string) Option {
	return func(stackdriver *Stackdriver) {
		stackdriver.Builder.GroupBys = groupBys
	}
}

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