Cannot scrape URI on a different port

[milesbxf]

Hi there, thanks for a very useful project. I noticed an issue running this alongside NGINX with VTS.

We expose the VTS status reports on a virtual server running on port 8080, with IP whitelisting to ensure they can only be accessed from localhost, for security. This is using the following NGINX config (vhost_traffic_status_zone is specified elsewhere):

    server {
        listen      8080;
        server_name localhost;

        # Allow localhost (for health checks)
        allow 127.0.0.1;
        deny all;

        # Expose VTS metrics (only on localhost for security)

        location = /vts/format/html {
            # Exposes vhost traffic status as a HTML report
            vhost_traffic_status_display;
            vhost_traffic_status_display_format html;
        }
        location = /vts/format/json {
            # Exposes vhost traffic status as a JSON report (the HTML format
            # relies on this URL to retrieve data)
            # vts exporter also scrapes from this URL
            vhost_traffic_status_display;
            vhost_traffic_status_display_format json;
        }
    }

We then run the VTS exporter via the Docker Hub image (digest 8d14166508a5b19ccfd8d75b8933c52f327c7ba5fe728267cd6dc2eb869fd049), specifying NGINX_STATUS=http://localhost:8080/vts/format/json. This URL works fine with curl, but when trying to retrieve metrics, the exporter logs fetchHTTP failed parse "http://localhost:8080/vts/format/json": first path segment in URL cannot contain colon.

This is potentially to do with a change to URL parsing in Go 1.8, although I've not investigated fully: golang/go#19297

Our workaround for now is just to move the vts endpoints to a virtual server listening on port 80, but it'd be really useful to be able to use a different port. Thanks!

[sysulq]

I am sorry but it seems ok in my mac.

• download and run

  docker pull sophos/nginx-vts-exporter
  docker run  -ti -p 9913:9913 --rm --env NGINX_STATUS=http://localhost:9090/vts/format/json sophos/nginx-vts-exporter

• nginx configuration

  server {
      listen      9090;
      server_name localhost;
  
      location = /vts/format/html {
          # Exposes vhost traffic status as a HTML report
          vhost_traffic_status_display;
          vhost_traffic_status_display_format html;
      }
      location = /vts/format/json {
          # Exposes vhost traffic status as a JSON report (the HTML format
          # relies on this URL to retrieve data)
          # vts exporter also scrapes from this URL
          vhost_traffic_status_display;
          vhost_traffic_status_display_format json;
      }
  }

• logs

  
  Using default tag: latest
  latest: Pulling from sophos/nginx-vts-exporter
  88286f41530e: Already exists
  356cc8ae0daf: Pull complete
  6d7f6aaa8b5f: Pull complete
  fbdfa9725ab4: Pull complete
  Digest: sha256:8d14166508a5b19ccfd8d75b8933c52f327c7ba5fe728267cd6dc2eb869fd049
  Status: Downloaded newer image for sophos/nginx-vts-exporter:latest

2017/08/08 02:03:19 Starting nginx_vts_exporter (version=0.4, branch=fix-docker-error, revision=0f3dbb44a86340d65bf3d6abbcc0ee88663cb419) 2017/08/08 02:03:19 Build context (go=go1.8, user=Administrator@LS--20151110SAS, date=20170316-03:16:26) 2017/08/08 02:03:19 Starting Server at : :9913 2017/08/08 02:03:19 Metrics endpoint: /metrics 2017/08/08 02:03:19 Metrics namespace: nginx 2017/08/08 02:03:19 Scraping information from : http://localhost:9090/vts/format/json