integer divide by zero

[christophefromparis]

I'm using the tricksterio/trickster:0.0.11 image with Prometheus and I receive several times the same error: integer divide by zero

10/04/2018 16:55:142018/04/10 14:55:14 http: panic serving 10.42.90.128:37778: runtime error: integer divide by zero
10/04/2018 16:55:14goroutine 3022 [running]:
10/04/2018 16:55:14net/http.(*conn).serve.func1(0xc42387a8c0)
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:1697 +0xd0
10/04/2018 16:55:14panic(0x772e60, 0x9fe640)
10/04/2018 16:55:14 /usr/local/go/src/runtime/panic.go:491 +0x283
10/04/2018 16:55:14main.alignStepBoundaries(...)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/handlers.go:763
10/04/2018 16:55:14main.(*TricksterHandler).buildRequestContext(0xc42013e000, 0x9d2960, 0xc42012dae0, 0xc4212da200, 0xc420ae3b90)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/handlers.go:393 +0x2b85
10/04/2018 16:55:14main.(*TricksterHandler).promQueryRangeHandler(0xc42013e000, 0x9d2960, 0xc42012dae0, 0xc4212da200)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/handlers.go:120 +0x4d
10/04/2018 16:55:14main.(*TricksterHandler).(main.promQueryRangeHandler)-fm(0x9d2960, 0xc42012dae0, 0xc4212da200)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/main.go:58 +0x48
10/04/2018 16:55:14net/http.HandlerFunc.ServeHTTP(0xc4201568f0, 0x9d2960, 0xc42012dae0, 0xc4212da200)
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:1918 +0x44
10/04/2018 16:55:14github.com/comcast/trickster/vendor/github.com/gorilla/mux.(*Router).ServeHTTP(0xc420130690, 0x9d2960, 0xc42012dae0, 0xc4212da200)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/vendor/github.com/gorilla/mux/mux.go:159 +0xed
10/04/2018 16:55:14github.com/comcast/trickster/vendor/github.com/gorilla/handlers.CompressHandlerLevel.func1(0x9d2ea0, 0xc427795a40, 0xc42015b800)
10/04/2018 16:55:14 /go/src/github.com/comcast/trickster/vendor/github.com/gorilla/handlers/compress.go:146 +0x462
10/04/2018 16:55:14net/http.HandlerFunc.ServeHTTP(0xc420115080, 0x9d2ea0, 0xc427795a40, 0xc42015b800)
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:1918 +0x44
10/04/2018 16:55:14net/http.serverHandler.ServeHTTP(0xc420120680, 0x9d2ea0, 0xc427795a40, 0xc42015b800)
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:2619 +0xb4
10/04/2018 16:55:14net/http.(*conn).serve(0xc42387a8c0, 0x9d36e0, 0xc4236f9280)
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:1801 +0x71d
10/04/2018 16:55:14created by net/http.(*Server).Serve
10/04/2018 16:55:14 /usr/local/go/src/net/http/server.go:2720 +0x288

[jranson]

@christophefromparis Will take a look today and root cause. Thank you for the report!

[jranson]

@christophefromparis it looks like somehow the Step size is not being picked up so the math is failing. That's a curious condition because it shouldn't happen! I'll add in a sanity check to see if that will fix it up while we figure out how it's happening in the first place.

[jranson]

Fixed in #31