// alertmanagersFromGroup extracts a list of alertmanagers from a target group and an associcated
// AlertmanagerConfig.
func alertmanagerFromGroup(tg *config.TargetGroup, cfg *config.AlertmanagerConfig) ([]alertmanager, error) {
var res []alertmanager
for _, lset := range tg.Targets {
// Set configured scheme as the initial scheme label for overwrite.
lset[model.SchemeLabel] = model.LabelValue(cfg.Scheme)
lset[pathLabel] = model.LabelValue(postPath(cfg.PathPrefix))
// Combine target labels with target group labels.
for ln, lv := range tg.Labels {
if _, ok := lset[ln]; !ok {
lset[ln] = lv
}
}
lset := relabel.Process(lset, cfg.RelabelConfigs...)
if lset == nil {
continue
}
// addPort checks whether we should add a default port to the address.
// If the address is not valid, we don't append a port either.
addPort := func(s string) bool {
// If we can split, a port exists and we don't have to add one.
if _, _, err := net.SplitHostPort(s); err == nil {
return false
}
// If adding a port makes it valid, the previous error
// was not due to an invalid address and we can append a port.
_, _, err := net.SplitHostPort(s + ":1234")
return err == nil
}
// If it's an address with no trailing port, infer it based on the used scheme.
if addr := string(lset[model.AddressLabel]); addPort(addr) {
// Addresses reaching this point are already wrapped in [] if necessary.
switch lset[model.SchemeLabel] {
case "http", "":
addr = addr + ":80"
case "https":
addr = addr + ":443"
default:
return nil, fmt.Errorf("invalid scheme: %q", cfg.Scheme)
}
lset[model.AddressLabel] = model.LabelValue(addr)
}
if err := config.CheckTargetAddress(lset[model.AddressLabel]); err != nil {
return nil, err
}
// Meta labels are deleted after relabelling. Other internal labels propagate to
// the target which decides whether they will be part of their label set.
for ln := range lset {
if strings.HasPrefix(string(ln), model.MetaLabelPrefix) {
delete(lset, ln)
}
}
res = append(res, alertmanagerLabels(lset))
}
return res, nil
}
// populateLabels builds a label set from the given label set and scrape configuration.
// It returns a label set before relabeling was applied as the second return value.
// Returns a nil label set if the target is dropped during relabeling.
func populateLabels(lset model.LabelSet, cfg *config.ScrapeConfig) (res, orig model.LabelSet, err error) {
if _, ok := lset[model.AddressLabel]; !ok {
return nil, nil, fmt.Errorf("no address")
}
// Copy labels into the labelset for the target if they are not
// set already. Apply the labelsets in order of decreasing precedence.
scrapeLabels := model.LabelSet{
model.SchemeLabel: model.LabelValue(cfg.Scheme),
model.MetricsPathLabel: model.LabelValue(cfg.MetricsPath),
model.JobLabel: model.LabelValue(cfg.JobName),
}
for ln, lv := range scrapeLabels {
if _, ok := lset[ln]; !ok {
lset[ln] = lv
}
}
// Encode scrape query parameters as labels.
for k, v := range cfg.Params {
if len(v) > 0 {
lset[model.LabelName(model.ParamLabelPrefix+k)] = model.LabelValue(v[0])
}
}
preRelabelLabels := lset
lset = relabel.Process(lset, cfg.RelabelConfigs...)
// Check if the target was dropped.
if lset == nil {
return nil, nil, nil
}
// addPort checks whether we should add a default port to the address.
// If the address is not valid, we don't append a port either.
addPort := func(s string) bool {
// If we can split, a port exists and we don't have to add one.
if _, _, err := net.SplitHostPort(s); err == nil {
return false
}
// If adding a port makes it valid, the previous error
// was not due to an invalid address and we can append a port.
_, _, err := net.SplitHostPort(s + ":1234")
return err == nil
}
// If it's an address with no trailing port, infer it based on the used scheme.
if addr := string(lset[model.AddressLabel]); addPort(addr) {
// Addresses reaching this point are already wrapped in [] if necessary.
switch lset[model.SchemeLabel] {
case "http", "":
addr = addr + ":80"
case "https":
addr = addr + ":443"
default:
return nil, nil, fmt.Errorf("invalid scheme: %q", cfg.Scheme)
}
lset[model.AddressLabel] = model.LabelValue(addr)
}
if err := config.CheckTargetAddress(lset[model.AddressLabel]); err != nil {
return nil, nil, err
}
// Meta labels are deleted after relabelling. Other internal labels propagate to
// the target which decides whether they will be part of their label set.
for ln := range lset {
if strings.HasPrefix(string(ln), model.MetaLabelPrefix) {
delete(lset, ln)
}
}
// Default the instance label to the target address.
if _, ok := lset[model.InstanceLabel]; !ok {
lset[model.InstanceLabel] = lset[model.AddressLabel]
}
return lset, preRelabelLabels, nil
}
// targetsFromGroup builds targets based on the given TargetGroup and config.
func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) ([]*Target, error) {
tm.mtx.RLock()
defer tm.mtx.RUnlock()
targets := make([]*Target, 0, len(tg.Targets))
for i, labels := range tg.Targets {
for k, v := range cfg.Params {
if len(v) > 0 {
labels[model.LabelName(model.ParamLabelPrefix+k)] = model.LabelValue(v[0])
}
}
// Copy labels into the labelset for the target if they are not
// set already. Apply the labelsets in order of decreasing precedence.
labelsets := []model.LabelSet{
tg.Labels,
{
model.SchemeLabel: model.LabelValue(cfg.Scheme),
model.MetricsPathLabel: model.LabelValue(cfg.MetricsPath),
model.JobLabel: model.LabelValue(cfg.JobName),
},
}
for _, lset := range labelsets {
for ln, lv := range lset {
if _, ok := labels[ln]; !ok {
labels[ln] = lv
}
}
}
if _, ok := labels[model.AddressLabel]; !ok {
return nil, fmt.Errorf("instance %d in target group %s has no address", i, tg)
}
preRelabelLabels := labels
labels, err := Relabel(labels, cfg.RelabelConfigs...)
if err != nil {
return nil, fmt.Errorf("error while relabeling instance %d in target group %s: %s", i, tg, err)
}
// Check if the target was dropped.
if labels == nil {
continue
}
// If no port was provided, infer it based on the used scheme.
addr := string(labels[model.AddressLabel])
if !strings.Contains(addr, ":") {
switch labels[model.SchemeLabel] {
case "http", "":
addr = fmt.Sprintf("%s:80", addr)
case "https":
addr = fmt.Sprintf("%s:443", addr)
default:
panic(fmt.Errorf("targetsFromGroup: invalid scheme %q", cfg.Scheme))
}
labels[model.AddressLabel] = model.LabelValue(addr)
}
if err = config.CheckTargetAddress(labels[model.AddressLabel]); err != nil {
return nil, err
}
for ln := range labels {
// Meta labels are deleted after relabelling. Other internal labels propagate to
// the target which decides whether they will be part of their label set.
if strings.HasPrefix(string(ln), model.MetaLabelPrefix) {
delete(labels, ln)
}
}
tr := NewTarget(cfg, labels, preRelabelLabels)
targets = append(targets, tr)
}
return targets, nil
}