{"action":"closed","issue":{"url":"https://api.github.com/repos/go-kit/kit/issues/103","labels_url":"https://api.github.com/repos/go-kit/kit/issues/103/labels{/name}","comments_url":"https://api.github.com/repos/go-kit/kit/issues/103/comments","events_url":"https://api.github.com/repos/go-kit/kit/issues/103/events","html_url":"https://github.com/go-kit/kit/issues/103","id":102089665,"number":103,"title":"log.Caller results \"unsupported value kind\"","user":{"login":"tgulacsi","id":256074,"avatar_url":"https://avatars.githubusercontent.com/u/256074?v=3","gravatar_id":"","url":"https://api.github.com/users/tgulacsi","html_url":"https://github.com/tgulacsi","followers_url":"https://api.github.com/users/tgulacsi/followers","following_url":"https://api.github.com/users/tgulacsi/following{/other_user}","gists_url":"https://api.github.com/users/tgulacsi/gists{/gist_id}","starred_url":"https://api.github.com/users/tgulacsi/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/tgulacsi/subscriptions","organizations_url":"https://api.github.com/users/tgulacsi/orgs","repos_url":"https://api.github.com/users/tgulacsi/repos","events_url":"https://api.github.com/users/tgulacsi/events{/privacy}","received_events_url":"https://api.github.com/users/tgulacsi/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-08-20T08:31:18Z","updated_at":"2015-08-20T13:06:40Z","closed_at":"2015-08-20T13:06:40Z","body":"With the logger `Log` of\r\n\r\n```\r\n    logger = log.NewContext(log.NewLogfmtLogger(os.Stderr)).\r\n        With(\"ts\", log.DefaultTimestampUTC,\r\n        \"caller\", log.Caller(6))\r\n    Log = levels.New(logger)\r\n```\r\n\r\nI get \r\n```ts=2015-08-20T08:17:12Z caller=\"unsupported value type\" level=debug msg=\"reference date format in dataURL: 2006/1/2\"\r\n```\r\n\r\nIf I change the `log.Valuer` to `func() string`, then everything works.\r\nI think maybe a fmt.Stringer would be enough (or anything what gopkg.in/logfmt.v0 accepts)."}}