From 7ce9f727e74f37bdf955fb2c41cd4e2beaa8a082 Mon Sep 17 00:00:00 2001 From: Ling Huang Date: Mon, 15 Jun 2020 20:34:58 -0400 Subject: [PATCH] Initialize the labels map in the response. (#264) Fixes the following error when the `labels` is not initialized: ``` Container logs: level=info ts=2020-03-02T03:17:42.590Z caller=main.go:293 msg="Starting Stackdriver Prometheus sidecar" version="(version=0.7.3, branch=master, revision=2548e8a7b383adc9217afe8570247ea84e3ef2c0)" level=info ts=2020-03-02T03:17:42.591Z caller=main.go:294 build_context="(go=go1.12, user=kbuilder@kokoro-gcp-ubuntu-prod-40088225, date=20200206-15:24:17)" level=info ts=2020-03-02T03:17:42.591Z caller=main.go:295 host_details="(Linux 4.14.138+ #1 SMP Tue Sep 3 02:58:08 PDT 2019 x86_64 apigee-metrics-v111-fd6fj (none))" level=info ts=2020-03-02T03:17:42.592Z caller=main.go:296 fd_limits="(soft=1048576, hard=1048576)" panic: assignment to entry in nil map ``` Labels can be optionally extracted from OC_RESOURCE_TYPE and OC_RESOURCE_LABELS env vars (https://github.com/census-instrumentation/opencensus-go/blob/1901b56b9515b0c34f5d25a5bce982dfc543d64b/resource/resource.go#L30). In case those envs are not set, labels will not be initialized: https://github.com/census-instrumentation/opencensus-go/blob/1901b56b9515b0c34f5d25a5bce982dfc543d64b/resource/resource.go#L98 For the case here, we are in fact sending metrics to Stackdriver. So OC_RESOURCE_TYPE and OC_RESOURCE_LABELS may not be needed. But we should init the Labels field. --- stackdriver.go | 3 +++ 1 file changed, 3 insertions(+) diff --git a/stackdriver.go b/stackdriver.go index 7524b44..fc96955 100644 --- a/stackdriver.go +++ b/stackdriver.go @@ -346,6 +346,9 @@ func NewExporter(o Options) (*Exporter, error) { } // Populate internal resource labels for defaulting project_id, location, and // generic resource labels of applicable monitored resources. + if res.Labels == nil { + res.Labels = make(map[string]string) + } res.Labels[stackdriverProjectID] = o.ProjectID res.Labels[resourcekeys.CloudKeyZone] = o.Location res.Labels[stackdriverGenericTaskNamespace] = "default"