Method AddUserRegistry

pkg/util/metrics_helper.go:590–615

AddUserRegistry adds an user registry. If user already has a registry, previous registry is removed, but latest metric values are preserved in order to avoid counter resets.

(user string, reg *prometheus.Registry)

// previous registry is removed, but latest metric values are preserved
// in order to avoid counter resets.
func (r *UserRegistries) AddUserRegistry(user string, reg *prometheus.Registry) {
	r.regsMu.Lock()
	defer r.regsMu.Unlock()

	// Soft-remove user registry, if user has one already.
	for idx := 0; idx < len(r.regs); {
		if r.regs[idx].user != user {
			idx++
			continue
		}

		if r.softRemoveUserRegistry(&r.regs[idx]) {
			// Keep it.
			idx++
		} else {
			// Remove it.
			r.regs = append(r.regs[:idx], r.regs[idx+1:]...)
		}
	}

	// New registries must be added to the end of the list, to guarantee stability.
	r.regs = append(r.regs, UserRegistry{
		user: user,
		reg:  reg,
	})
}

// RemoveUserRegistry removes all Prometheus registries for a given user.
// If hard is true, registry is removed completely.