config

package
Version: v0.5.28 Latest Latest
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Published: Mar 4, 2021 License: Apache-2.0 Imports: 10 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func SetPrestoConfig

func SetPrestoConfig(cfg *Config) error

func URLMustParse

func URLMustParse(s string) config.URL

Types

type Config

type Config struct {
	Environment            config.URL           `json:"environment" pflag:",Environment endpoint for Presto to use"`
	DefaultRoutingGroup    string               `json:"defaultRoutingGroup" pflag:",Default Presto routing group"`
	DefaultUser            string               `json:"defaultUser" pflag:",Default Presto user"`
	UseNamespaceAsUser     bool                 `json:"useNamespaceAsUser" pflag:",Use the K8s namespace as the user"`
	RoutingGroupConfigs    []RoutingGroupConfig `json:"routingGroupConfigs" pflag:"-,A list of cluster configs. Each of the configs corresponds to a service cluster"`
	RefreshCacheConfig     RefreshCacheConfig   `json:"refreshCacheConfig" pflag:"Refresh cache config"`
	ReadRateLimiterConfig  RateLimiterConfig    `json:"readRateLimiterConfig" pflag:"Rate limiter config for read requests going to Presto"`
	WriteRateLimiterConfig RateLimiterConfig    `json:"writeRateLimiterConfig" pflag:"Rate limiter config for write requests going to Presto"`
}

Presto plugin configs

func GetPrestoConfig

func GetPrestoConfig() *Config

Retrieves the current config value or default.

func (Config) GetPFlagSet

func (cfg Config) GetPFlagSet(prefix string) *pflag.FlagSet

GetPFlagSet will return strongly types pflags for all fields in Config and its nested types. The format of the flags is json-name.json-sub-name... etc.

type RateLimiterConfig added in v0.3.18

type RateLimiterConfig struct {
	Rate  int64 `json:"rate" pflag:",Allowed rate of calls per second."`
	Burst int   `json:"burst" pflag:",Allowed burst rate of calls per second."`
}

To execute a single Presto query from a user's point of view, we actually need to send 5 different requests to Presto. Together these requests (i.e. queries) take care of retrieving the data, saving it to an external table, and performing cleanup.

The Presto plugin currently uses a single allocation token for each set of 5 requests which correspond to a single user query. These means that in total, Flyte is able to work on 'PrestoConfig.RoutingGroups[routing_group_name].Limit' user queries at a time as configured in the configurations for the Presto plugin. This means means that at most, Flyte will be working on this number of user Presto queries at a time for each of the configured Presto routing groups.

In addition, these 2 rate limiters control the rate at which requests are sent to Presto for read and write requests coming from this client. This includes requests to execute queries (write), requests to get the status of a query through the auto-refresh cache (read), and requests to cancel queries (write). Together with allocation tokens, these rate limiters will ensure that the rate of requests and the number of concurrent requests going to Presto don't overload the cluster.

There is also another important aspect to consider in terms of how the resource manager (where allocation tokens get created from) interplays with the rate limiters. From the write side of things (e.g. executing a query), if the write rate limiter is low then it will block executing queries until the rate falls below the limit. Even if the rate is below the limit, if queries take a long time to execute, then you will be blocked at the resource manager level which only allows a certain number of concurrent queries to execute at any given time. Similarly, in more extreme cases, if both the resource manager and the write limiter are configured to support a large number of queries but the auto refresh cache size is small, then the cache will fill up and items will gets evicted due to the cache's LRU nature before the Flyte propeller workers get a chance to update the status of these items.

type RefreshCacheConfig

type RefreshCacheConfig struct {
	Name         string          `json:"name" pflag:",The name of the rate limiter"`
	SyncPeriod   config.Duration `json:"syncPeriod" pflag:",The duration to wait before the cache is refreshed again"`
	Workers      int             `json:"workers" pflag:",Number of parallel workers to refresh the cache"`
	LruCacheSize int             `json:"lruCacheSize" pflag:",Size of the cache"`
}

type RoutingGroupConfig

type RoutingGroupConfig struct {
	Name                             string  `json:"name" pflag:",The name of a given Presto routing group"`
	Limit                            int     `json:"limit" pflag:",Resource quota (in the number of outstanding requests) of the routing group"`
	ProjectScopeQuotaProportionCap   float64 `` /* 185-byte string literal not displayed */
	NamespaceScopeQuotaProportionCap float64 `` /* 189-byte string literal not displayed */
}

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