/
filter.go
378 lines (352 loc) · 10.9 KB
/
filter.go
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package alerts
import (
"path/filepath"
"sort"
"strconv"
"strings"
"time"
"github.com/libopenstorage/openstorage/api"
)
// Filters is a list of Filters that can be sorted
type Filters []Filter
func (fs Filters) Len() int {
return len(fs)
}
func (fs Filters) Less(i, j int) bool {
return (fs)[i].GetFilterType() < (fs)[j].GetFilterType()
}
func (fs Filters) Swap(i, j int) {
(fs)[i], (fs)[j] = (fs)[j], (fs)[i]
}
// Filter is something that matches an alert.
type Filter interface {
GetFilterType() FilterType
GetValue() interface{}
Match(alert *api.Alert) (bool, error)
}
// FilterType contains a filter type.
type FilterType int
// FilterType constants.
// Please note that the ordering of these filter type constants is very important
// since filters are sorted based on this ordering and such sorting is done to
// properly query kvdb tree structure.
//
// kvdb tree struct is defined as alerts/<resourceType>/<alertType>/<resourceID>/data
//
// Input filters are sorted based
const (
// This group of filters, when used to fetch directly from kvdb, target all entries in kvdb.
// Therefore, these filters are considered inefficient in fetching. They fetch _all_ entries
// and then filter out the fetched entries. Due to this reason these filters need to be handled
// individually in the Delete method implementation.
// CustomFilter is based on a user defined function (UDF). All alert entries are fetched from kvdb
// and then passed through UDF. Entries that match are returned. Therefore, this filter does not query
// kvdb efficiently.
CustomFilter FilterType = iota
// timeSpanFilter is based on a start and end timestamp. All alert entries are fetched from kvdb
// and then parsed to see if the timestamp for each entry falls within the start and end timestamp
// of this filter. Matching entries are returned.
// This filter is not an efficient filter.
timeSpanFilter
// countSpanFilter parses on the count value of alert entries. This filter requires pulling all entries
// and is, therefore, not an efficient filter.
countSpanFilter
// minSeverityFilter matches on the alert severity if it is more than or equal to severity set in this filter.
// This filter can be used for fetching alerts directly but it not an efficient filter. Therefore, the
// recommended approach is to fetch alerts from kvdb using one of the efficient filters, then
// filter the fetched alerts using this filter.
minSeverityFilter
// flagCheckFilter matches on the clear alert flag. This filter should be used for filtering the fetched
// alerts and not directly for fetching alerts from kvdb since this is not an efficient filter.
flagCheckFilter
// matchResourceIDFilter takes only one argument, i.e., resource id. It fetches all entries from kvdb
// then parses them to see resource id's are matching. Matching entries are returned.
// This filter is not an efficient filter since it requires pulling all entries.
// Recommend to use resourceIDFilter if resource type and alert type info is also known for
// efficient querying.
matchResourceIDFilter
// matchAlertTypeFilter takes only one argume, i.e., an alert type. It fetches all entries from kvdb
// then parses them to see alert type is matching. Matching entries are returned.
// This filter is not an efficient filter since it requires pulling all entries.
// Recommend to use alertTypeFilter if resource type info is also known for
// efficient querying.
matchAlertTypeFilter
// Filter types listed below provide more efficient querying into kvdb by directly querying kvdb sub tree.
// These filters reach a sub tree in kvdb and only fetch some alerts, therefore, these are called efficient
// filters.
// resourceTypeFilter takes resource type and fetches all alert entries under that resource type prefix.
// Since resource type is a top level indexing of data, it always performs querying efficiently without
// requiring any further filtering.
resourceTypeFilter
// alertTypeFilter draws alert entries under a prefix based on resourceType/alertType.
// In other words, to use this filter you would need to provide both inputs.
// This filter also fetches only the required contents which do not require further filtering.
alertTypeFilter
// resourceIDFilter, similarly, requires three inputs, i.e., resourceID, alert type and
// resource type. This filter also fetches efficiently based on prefix defined by these three
// inputs and requires no further filtering on the fetched contents.
resourceIDFilter
)
// filter implements Filter interface.
type filter struct {
filterType FilterType
value interface{}
options []Option
}
// timeZone contains information about time window.
type timeZone struct {
start time.Time
stop time.Time
}
type alertInfo struct {
alertType int64
resourceType api.ResourceType
resourceID string
}
func (f *filter) GetFilterType() FilterType {
return f.filterType
}
func (f *filter) GetValue() interface{} {
return f.value
}
func (f *filter) Match(alert *api.Alert) (bool, error) {
switch f.filterType {
case CustomFilter:
v, ok := f.value.(func(alert *api.Alert) (bool, error))
if !ok {
return false, typeAssertionError.
Tag("custom filter").
Tag("func Match")
}
return v(alert)
case timeSpanFilter:
v, ok := f.value.(timeZone)
if !ok {
return false, typeAssertionError.
Tag("timeSpanFilter").
Tag("func Match")
}
if alert.Timestamp.Seconds >= v.start.Unix() &&
alert.Timestamp.Seconds <= v.stop.Unix() {
return true, nil
}
return false, nil
case matchResourceIDFilter:
v, ok := f.value.(string)
if !ok {
return false, typeAssertionError.
Tag("matchResourceIDFilter").
Tag("func Match")
}
if alert.ResourceId == v {
return true, nil
}
return false, nil
case matchAlertTypeFilter:
v, ok := f.value.(int64)
if !ok {
return false, typeAssertionError.
Tag("matchAlertTypeFilter").
Tag("func Match")
}
if alert.AlertType == v {
return true, nil
}
return false, nil
case countSpanFilter:
v, ok := f.value.([]int64)
if !ok {
return false, typeAssertionError.
Tag("countSpanFilter").
Tag("func Match")
}
if len(v) != 2 {
return false, incorrectFilterValue.
Tag("countSpanFilter").
Tag("func Match")
}
if alert.Count >= v[0] && alert.Count <= v[1] {
return true, nil
}
return false, nil
case minSeverityFilter:
v, ok := f.value.(api.SeverityType)
if !ok {
return false, typeAssertionError.
Tag("minSeverityFilter").
Tag("func Match")
}
switch v {
case api.SeverityType_SEVERITY_TYPE_NONE:
return true, nil
case api.SeverityType_SEVERITY_TYPE_NOTIFY,
api.SeverityType_SEVERITY_TYPE_WARNING,
api.SeverityType_SEVERITY_TYPE_ALARM:
if alert.Severity <= v &&
alert.Severity != api.SeverityType_SEVERITY_TYPE_NONE {
return true, nil
}
}
return false, nil
case flagCheckFilter:
v, ok := f.value.(bool)
if !ok {
return false, typeAssertionError.
Tag("flagCheckFilter").
Tag("func Match")
}
if alert.Cleared == v {
return true, nil
}
return false, nil
// Cases below are for efficient filters
// -------------------------------------
case resourceTypeFilter:
v, ok := f.value.(api.ResourceType)
if !ok {
return false, typeAssertionError.
Tag("resourceTypeFilter").
Tag("func Match")
}
if alert.Resource == v {
// iterate through options and match alert
for _, opt := range f.options {
if w, ok := opt.GetValue().(Filter); !ok {
return false, typeAssertionError.
Tag("invalid option").
Tag("resourceTypeFilter").
Tag("func Match")
} else {
if matched, err := w.Match(alert); err != nil {
return false, err
} else {
if !matched {
return false, nil
}
}
}
}
return true, nil
}
return false, nil
case alertTypeFilter:
v, ok := f.value.(alertInfo)
if !ok {
return false, typeAssertionError.
Tag("alertTypeFilter").
Tag("func Match")
}
if alert.AlertType == v.alertType &&
alert.Resource == v.resourceType {
// iterate through options and match alert
for _, opt := range f.options {
if w, ok := opt.GetValue().(Filter); !ok {
return false, typeAssertionError.
Tag("alertTypeFilter").
Tag("func Match")
} else {
if matched, err := w.Match(alert); err != nil {
return false, err
} else {
if !matched {
return false, nil
}
}
}
}
return true, nil
}
return false, nil
case resourceIDFilter:
v, ok := f.value.(alertInfo)
if !ok {
return false, typeAssertionError.
Tag("resourceIDFilter").
Tag("func Match")
}
if alert.AlertType == v.alertType &&
alert.Resource == v.resourceType &&
alert.ResourceId == v.resourceID {
// iterate through options and match alert
for _, opt := range f.options {
if w, ok := opt.GetValue().(Filter); !ok {
return false, typeAssertionError.
Tag("resourceIDFilter").
Tag("func Match")
} else {
if matched, err := w.Match(alert); err != nil {
return false, err
} else {
if !matched {
return false, nil
}
}
}
}
return true, nil
}
return false, nil
default:
return false, invalidFilterType.Tag("func Match")
}
}
// getUniqueKeysFromFilters analyzes filters and outputs a map of unique keys such that
// these keys do not point to sub trees of one another.
func getUniqueKeysFromFilters(filters ...Filter) (map[string]bool, error) {
keys := make(map[string]bool)
// sort filters so we know how to query
if len(filters) > 0 {
sort.Sort(Filters(filters))
for _, filter := range filters {
key := kvdbKey
switch filter.GetFilterType() {
// only these filter types benefit from efficient kvdb querying.
// for everything else we enumerate and then filter.
case resourceTypeFilter:
v, ok := filter.GetValue().(api.ResourceType)
if !ok {
return nil, typeAssertionError
}
key = filepath.Join(key, v.String())
case alertTypeFilter:
v, ok := filter.GetValue().(alertInfo)
if !ok {
return nil, typeAssertionError
}
key = filepath.Join(key,
v.resourceType.String(), strconv.FormatInt(v.alertType, 16))
case resourceIDFilter:
v, ok := filter.GetValue().(alertInfo)
if !ok {
return nil, typeAssertionError
}
key = filepath.Join(key,
v.resourceType.String(), strconv.FormatInt(v.alertType, 16), v.resourceID)
}
keyPath, _ := filepath.Split(key)
keyPath = strings.Trim(keyPath, "/")
if !keys[keyPath] {
keys[key] = true
}
}
} else {
keys[kvdbKey] = true
}
// remove all keys that access sub tree of another key
var keysToDelete []string
for key := range keys {
keyPath := key
for len(keyPath) > 0 {
keyPath, _ = filepath.Split(keyPath)
keyPath = strings.Trim(keyPath, "/")
if keys[keyPath] {
keysToDelete = append(keysToDelete, key)
break
}
}
}
for _, key := range keysToDelete {
delete(keys, key)
}
return keys, nil
}