lib/promscrape/discovery/dockerswarm: fix query encoding of filters (#3586)

Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>

docs/CHANGELOG.md

@@ -29,6 +29,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * BUGFIX: properly parse floating-point numbers without integer or fractional parts such as `.123` and `20.` during [data import](https://docs.victoriametrics.com/#how-to-import-time-series-data). See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3544).
 * BUGFIX: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): properly parse durations with uppercase suffixes such as `10S`, `5MS`, `1W`, etc. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3589).
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): fix a panic during target discovery when `vmagent` runs with `-promscrape.dropOriginalLabels` command-line flag. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3580). The bug has been introduced in [v1.85.0](https://docs.victoriametrics.com/CHANGELOG.html#v1850).
+* BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): [dockerswarm_sd_configs](https://docs.victoriametrics.com/sd_configs.html#dockerswarm_sd_configs): properly encode `filters` field. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3579)
 
 
 ## [v1.85.3](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.85.3)

lib/promscrape/discovery/dockerswarm/api.go

@@ -63,20 +63,16 @@ func (cfg *apiConfig) getAPIResponse(path string) ([]byte, error) {
 	return cfg.client.GetAPIResponse(path)
 }
 
+// Encodes filters as `map[string][]string` and then marshals it to JSON.
+// Reference: https://docs.docker.com/engine/api/v1.41/#tag/Task
 func getFiltersQueryArg(filters []Filter) string {
 	if len(filters) == 0 {
 		return ""
 	}
-	m := make(map[string]map[string]bool)
+
+	m := make(map[string][]string)
 	for _, f := range filters {
-		x := m[f.Name]
+		m[f.Name] = f.Values
-		if x == nil {
-			x = make(map[string]bool)
-			m[f.Name] = x
-		}
-		for _, value := range f.Values {
-			x[value] = true
-		}
 	}
 	buf, err := json.Marshal(m)
 	if err != nil {

lib/promscrape/discovery/dockerswarm/api_test.go

@@ -22,5 +22,11 @@ func TestGetFiltersQueryArg(t *testing.T) {
 			Name:   "xxx",
 			Values: []string{"aa"},
 		},
-	}, "%7B%22name%22%3A%7B%22bar%22%3Atrue%2C%22foo%22%3Atrue%7D%2C%22xxx%22%3A%7B%22aa%22%3Atrue%7D%7D")
+	}, "%7B%22name%22%3A%5B%22foo%22%2C%22bar%22%5D%2C%22xxx%22%3A%5B%22aa%22%5D%7D")
+	f([]Filter{
+		{
+			Name:   "desired-state",
+			Values: []string{"running", "shutdown"},
+		},
+	}, "%7B%22desired-state%22%3A%5B%22running%22%2C%22shutdown%22%5D%7D")
 }