target refresh failed: unexpected response status: 404 Not Found

[ToxicWar]

Hi,

I try to use stackdriver-prometheus-sidecar with my prometheus-server who installed used stable/prometheus helm chart.

I configure my stackdriver-prometheus-sidecar with --prometheus.api-address=http://127.0.0.1:9090/prometheus/, because in Prometheus deployment I use prefixURL.

Then when my pod with stackdriver-prometheus-sidecar I see errors like this and zero metrics in Stackdriver.

level=error ts=2018-12-31T07:41:16.764201212Z caller=cache.go:76 msg="refresh failed" err="unexpected response status: 404 Not Found"
level=warn ts=2018-12-31T07:42:13.044253069Z caller=manager.go:243 component="Prometheus reader" msg="Failed to build sample" err="get series information: retrieving target failed: target refresh failed: unexpected response status: 404 Not Found"

As I understand it's some problem with targetsURL, because service try get data from /api/v1/targets/metadata without using prefixURL specified in prometheus.api-address

targetsURL, err := cfg.prometheusURL.Parse(targets.DefaultAPIEndpoint)

[jkohen]

Thanks for the report. Release 0.3.1 includes the fix.