// Code generated by qtc from "expand-with-exprs.qtpl". DO NOT EDIT. // See https://github.com/valyala/quicktemplate for details. //line app/vmselect/prometheus/expand-with-exprs.qtpl:1 package prometheus //line app/vmselect/prometheus/expand-with-exprs.qtpl:1 import ( "fmt" "github.com/VictoriaMetrics/metricsql" ) // ExpandWithExprsResponse returns a webpage, which expands with templates in q MetricsQL. //line app/vmselect/prometheus/expand-with-exprs.qtpl:9 import ( qtio422016 "io" qt422016 "github.com/valyala/quicktemplate" ) //line app/vmselect/prometheus/expand-with-exprs.qtpl:9 var ( _ = qtio422016.Copy _ = qt422016.AcquireByteBuffer ) //line app/vmselect/prometheus/expand-with-exprs.qtpl:9 func StreamExpandWithExprsResponse(qw422016 *qt422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:9 qw422016.N().S(`Expand WITH expressions

MetricsQL query with optional WITH expressions:


MetricsQL query after expanding WITH expressions and applying other optimizations:

`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:37 streamwithExprsTutorial(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:37 qw422016.N().S(`
`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 func WriteExpandWithExprsResponse(qq422016 qtio422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 qw422016 := qt422016.AcquireWriter(qq422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 StreamExpandWithExprsResponse(qw422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 qt422016.ReleaseWriter(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 func ExpandWithExprsResponse(q string) string { //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 qb422016 := qt422016.AcquireByteBuffer() //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 WriteExpandWithExprsResponse(qb422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 qs422016 := string(qb422016.B) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 qt422016.ReleaseByteBuffer(qb422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 return qs422016 //line app/vmselect/prometheus/expand-with-exprs.qtpl:41 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:43 func streamexpandWithExprs(qw422016 *qt422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:44 if len(q) == 0 { //line app/vmselect/prometheus/expand-with-exprs.qtpl:45 return //line app/vmselect/prometheus/expand-with-exprs.qtpl:46 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:48 expr, err := metricsql.Parse(q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:49 if err != nil { //line app/vmselect/prometheus/expand-with-exprs.qtpl:49 qw422016.N().S(`Cannot parse query:`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:50 qw422016.E().V(err) //line app/vmselect/prometheus/expand-with-exprs.qtpl:51 } else { //line app/vmselect/prometheus/expand-with-exprs.qtpl:52 expr = metricsql.Optimize(expr) //line app/vmselect/prometheus/expand-with-exprs.qtpl:53 qw422016.E().Z(expr.AppendString(nil)) //line app/vmselect/prometheus/expand-with-exprs.qtpl:54 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 func writeexpandWithExprs(qq422016 qtio422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 qw422016 := qt422016.AcquireWriter(qq422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 streamexpandWithExprs(qw422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 qt422016.ReleaseWriter(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 func expandWithExprs(q string) string { //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 qb422016 := qt422016.AcquireByteBuffer() //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 writeexpandWithExprs(qb422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 qs422016 := string(qb422016.B) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 qt422016.ReleaseByteBuffer(qb422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 return qs422016 //line app/vmselect/prometheus/expand-with-exprs.qtpl:55 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:57 func StreamExpandWithExprsJSONResponse(qw422016 *qt422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:58 if len(q) == 0 { //line app/vmselect/prometheus/expand-with-exprs.qtpl:58 qw422016.N().S(`{"status": "error","error": "query string cannot be empty"}`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:63 return //line app/vmselect/prometheus/expand-with-exprs.qtpl:64 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:64 qw422016.N().S(`{`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:67 expr, err := metricsql.Parse(q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:68 if err != nil { //line app/vmselect/prometheus/expand-with-exprs.qtpl:68 qw422016.N().S(`"status": "error","error":`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:70 qw422016.E().Q(fmt.Sprintf("Cannot parse query: %s", err)) //line app/vmselect/prometheus/expand-with-exprs.qtpl:71 } else { //line app/vmselect/prometheus/expand-with-exprs.qtpl:72 expr = metricsql.Optimize(expr) //line app/vmselect/prometheus/expand-with-exprs.qtpl:72 qw422016.N().S(`"status": "success","expr":`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:74 qw422016.E().QZ(expr.AppendString(nil)) //line app/vmselect/prometheus/expand-with-exprs.qtpl:75 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:75 qw422016.N().S(`}`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 func WriteExpandWithExprsJSONResponse(qq422016 qtio422016.Writer, q string) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 qw422016 := qt422016.AcquireWriter(qq422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 StreamExpandWithExprsJSONResponse(qw422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 qt422016.ReleaseWriter(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 func ExpandWithExprsJSONResponse(q string) string { //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 qb422016 := qt422016.AcquireByteBuffer() //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 WriteExpandWithExprsJSONResponse(qb422016, q) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 qs422016 := string(qb422016.B) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 qt422016.ReleaseByteBuffer(qb422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 return qs422016 //line app/vmselect/prometheus/expand-with-exprs.qtpl:77 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:81 func streamwithExprsTutorial(qw422016 *qt422016.Writer) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:81 qw422016.N().S(`

Tutorial for WITH expressions in MetricsQL

Let's look at the following real query from Node Exporter Full dashboard: 

(
  (
    node_memory_MemTotal_bytes{instance=~"$node:$port", job=~"$job"}
      -
    node_memory_MemFree_bytes{instance=~"$node:$port", job=~"$job"}
  )
    /
  node_memory_MemTotal_bytes{instance=~"$node:$port", job=~"$job"}
)
  *
100

It is clear the query calculates the percentage of used memory for the given $node, $port and $job. Isn't it? :)

What's wrong with this query? Copy-pasted label filters for distinct timeseries which makes it easy to mistype these filters during modification. Let's simplify the query with WITH expressions: 

WITH (
    commonFilters = {instance=~"$node:$port",job=~"$job"}
)
(
  node_memory_MemTotal_bytes{commonFilters}
    -
  node_memory_MemFree_bytes{commonFilters}
)
  /
node_memory_MemTotal_bytes{commonFilters} * 100

Now label filters are located in a single place instead of three distinct places. The query mentions node_memory_MemTotal_bytes metric twice and {commonFilters} three times. WITH expressions may improve this: 

WITH (
    my_resource_utilization(free, limit, filters) = (limit{filters} - free{filters}) / limit{filters} * 100
)
my_resource_utilization(
  node_memory_MemFree_bytes,
  node_memory_MemTotal_bytes,
  {instance=~"$node:$port",job=~"$job"},
)

Now the template function my_resource_utilization() may be used for monitoring arbitrary resources - memory, CPU, network, storage, you name it.

Let's take another nice query from Node Exporter Full dashboard: 

(
  (
    (
      count(
        count(node_cpu_seconds_total{instance=~"$node:$port",job=~"$job"}) by (cpu)
      )
    )
      -
    avg(
      sum by (mode) (rate(node_cpu_seconds_total{mode='idle',instance=~"$node:$port",job=~"$job"}[5m]))
    )
  )
    *
  100
)
  /
count(
  count(node_cpu_seconds_total{instance=~"$node:$port",job=~"$job"}) by (cpu)
)

Do you understand what does this mess do? Is it manageable? :) WITH expressions are happy to help in a few iterations.

1. Extract common filters used in multiple places into a commonFilters variable: 

WITH (
    commonFilters = {instance=~"$node:$port",job=~"$job"}
)
(
  (
    (
      count(
        count(node_cpu_seconds_total{commonFilters}) by (cpu)
      )
    )
      -
    avg(
      sum by (mode) (rate(node_cpu_seconds_total{mode='idle',commonFilters}[5m]))
    )
  )
    *
  100
)
  /
count(
  count(node_cpu_seconds_total{commonFilters}) by (cpu)
)

2. Extract "count(count(...) by (cpu))" into cpuCount variable: 

WITH (
    commonFilters = {instance=~"$node:$port",job=~"$job"},
    cpuCount = count(count(node_cpu_seconds_total{commonFilters}) by (cpu))
)
(
  (
    cpuCount
      -
    avg(
      sum by (mode) (rate(node_cpu_seconds_total{mode='idle',commonFilters}[5m]))
    )
  )
    *
  100
) / cpuCount

3. Extract rate(...) part into cpuIdle variable, since it is clear now that this part calculates the number of idle CPUs: 

WITH (
    commonFilters = {instance=~"$node:$port",job=~"$job"},
    cpuCount = count(count(node_cpu_seconds_total{commonFilters}) by (cpu)),
    cpuIdle = sum(rate(node_cpu_seconds_total{mode='idle',commonFilters}[5m]))
)
((cpuCount - cpuIdle) * 100) / cpuCount

4. Put node_cpu_seconds_total{commonFilters} into its own varialbe with the name cpuSeconds: 

WITH (
    cpuSeconds = node_cpu_seconds_total{instance=~"$node:$port",job=~"$job"},
    cpuCount = count(count(cpuSeconds) by (cpu)),
    cpuIdle = sum(rate(cpuSeconds{mode='idle'}[5m]))
)
((cpuCount - cpuIdle) * 100) / cpuCount

Now the query became more clear comparing to the initial query.

WITH expressions may be nested and may be put anywhere. Try expanding the following query: 

WITH (
    f(a, b) = WITH (
        f1(x) = b-x,
        f2(x) = x+x
    ) f1(a)*f2(b)
) f(foo, with(x=bar) x)
`) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 func writewithExprsTutorial(qq422016 qtio422016.Writer) { //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 qw422016 := qt422016.AcquireWriter(qq422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 streamwithExprsTutorial(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 qt422016.ReleaseWriter(qw422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 } //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 func withExprsTutorial() string { //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 qb422016 := qt422016.AcquireByteBuffer() //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 writewithExprsTutorial(qb422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 qs422016 := string(qb422016.B) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 qt422016.ReleaseByteBuffer(qb422016) //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 return qs422016 //line app/vmselect/prometheus/expand-with-exprs.qtpl:268 }