README
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Cuirass (in development)
Cuirass is a latency and fault tolerance library inspired by hystrix written in Go. It provides isolation when accessing remote systems with support for fallback when things go wrong. Remote execution is protected with timeouts and circuit breakers to fail fast and let the system recover.
Run example
Get and run the example:
$ https://github.com/arjantop/cuirass.git
$ cd cuirass
$ go run examples/main.go
Sample output:
2014/11/12 12:15:54 context deadline exceeded
2014/11/12 12:15:54 Request => GetUserAccountCommand[FAILURE, FALLBACK_SUCCESS][4ms], GetPaymentInformationCommand[SUCCESS][6ms], GetUserAccountCommand[RESPONSE_FROM_CACHE][0ms]x2, GetOrderCommand[SUCCESS][64ms], CreditCardCommand[TIMEOUT][1000ms]
2014/11/12 12:15:59 Request => GetUserAccountCommand[SUCCESS][6ms], GetPaymentInformationCommand[SUCCESS][4ms], GetUserAccountCommand[SUCCESS, RESPONSE_FROM_CACHE][0ms]x2, GetOrderCommand[SUCCESS][172ms], CreditCardCommand[SUCCESS][965ms]
2014/11/12 12:16:00 Request => GetUserAccountCommand[SUCCESS][6ms], GetPaymentInformationCommand[SUCCESS][3ms], GetUserAccountCommand[SUCCESS, RESPONSE_FROM_CACHE][0ms]x2, GetOrderCommand[SUCCESS][136ms], CreditCardCommand[SUCCESS][929ms]
2014/11/12 12:16:01 context deadline exceeded
2014/11/12 12:16:01 Request => GetUserAccountCommand[SUCCESS][11ms], GetPaymentInformationCommand[SUCCESS][85ms], GetUserAccountCommand[SUCCESS, RESPONSE_FROM_CACHE][0ms]x2, GetOrderCommand[SUCCESS][149ms], CreditCardCommand[TIMEOUT][1000ms]
TODO
- Request Collapsing/Batching
Hystrix Dashboard
Cuirass metrics can be monitored using the hystrix-dashboard.
Documentation
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Index ¶
- Constants
- Variables
- type Command
- func (c *Command) CacheKey() string
- func (c *Command) Fallback(ctx context.Context) (interface{}, error)
- func (c *Command) Group() string
- func (c *Command) IsCacheable() bool
- func (c *Command) Name() string
- func (c *Command) Properties(cfg vaquita.DynamicConfig) *CommandProperties
- func (c *Command) Run(ctx context.Context) (interface{}, error)
- type CommandBuilder
- type CommandExecutor
- type CommandFunc
- type CommandProperties
- type Executor
- type SemaphoreFactory
Constants ¶
const ( ExecutionTimeoutDefault = 0 ExecutionMaxConcurrentRequestsDefault = 100 FallbackEnabledDefault = true RequestCacheEnabledDefault = true RequestLogEnabledDefault = true CircuitBreakerEnabledDefault = true CircuitBreakerRequestVolumeThresholdDefault = 20 CircuitBreakerSleepWindowDefault = 5000 * time.Millisecond CircuitBreakerErrorThresholdPercentageDefault = 50 CircuitBreakerForceOpenDefault = false CircuitBreakerForceClosedDefault = false )
Variables ¶
var ( UnknownPanic = errors.New("unknown panic") SemaphoreRejected = errors.New("semaphore rejected") )
var FallbackNotImplemented = errors.New("Fallback not implemented")
FallbackNotImplemented is the error returned by Cimmand.Fallback when no fallback function is configured.
Functions ¶
This section is empty.
Types ¶
type Command ¶
type Command struct {
// contains filtered or unexported fields
}
Command is a wrapper for a code that requires latency and fault tolerance (typically service call over the network).
func (*Command) IsCacheable ¶
IsCacheable returns true id the response of the command execution can be cached.
func (*Command) Properties ¶
func (c *Command) Properties(cfg vaquita.DynamicConfig) *CommandProperties
type CommandBuilder ¶
type CommandBuilder struct {
// contains filtered or unexported fields
}
CommandBuilder is a helper used for constructing new Commands.
func NewCommand ¶
func NewCommand(name string, run CommandFunc) *CommandBuilder
NewCommand constructs a new CommandBuilder with minimal required command implementation (name and primary function).
func (*CommandBuilder) Build ¶
func (b *CommandBuilder) Build() *Command
Build builds a command with all configured parameters.
func (*CommandBuilder) CacheKey ¶
func (b *CommandBuilder) CacheKey(cacheKey string) *CommandBuilder
CacheKey sets a cache key to the command being build. This means that the command response can be cached and reused for the execution of the same command with the same key.
func (*CommandBuilder) Fallback ¶
func (b *CommandBuilder) Fallback(fallback CommandFunc) *CommandBuilder
Fallback adds a fallback function to the command being built.
func (*CommandBuilder) Group ¶
func (b *CommandBuilder) Group(name string) *CommandBuilder
Group sets a group name for a command. The default group name is the name of the command. Group name is used for limiting the concurrent execution of the command for the entire group.
type CommandExecutor ¶
type CommandExecutor struct {
// contains filtered or unexported fields
}
CommandExecutor is an implementation of an Executor interface.
func NewExecutor ¶
func NewExecutor(cfg vaquita.DynamicConfig) *CommandExecutor
NewExecutor constructs a new empty executor.
func NewExecutorWithClock ¶
func NewExecutorWithClock(cfg vaquita.DynamicConfig, clock util.Clock) *CommandExecutor
func (*CommandExecutor) Exec ¶
func (e *CommandExecutor) Exec(ctx context.Context, cmd *Command) (result interface{}, err error)
Exec executes a command and handles command execution errors. If command fails with an error or panics Fallback function with fallback logic is executed. Every command execution is guarded by an internal circuit-breaker. Panics are recovered and returned as errors.
func (*CommandExecutor) IsCircuitBreakerOpen ¶
func (e *CommandExecutor) IsCircuitBreakerOpen(cmdName string) bool
func (*CommandExecutor) Metrics ¶
func (e *CommandExecutor) Metrics() *metrics.ExecutionMetrics
type CommandFunc ¶
A CommandFunc is a function that contains the primary or fallback logic for the command.
type CommandProperties ¶
type CommandProperties struct {
ExecutionTimeout vaquita.DurationProperty
ExecutionMaxConcurrentRequests vaquita.IntProperty
FallbackEnabled vaquita.BoolProperty
RequestCacheEnabled vaquita.BoolProperty
RequestLogEnabled vaquita.BoolProperty
CircuitBreaker *circuitbreaker.CircuitBreakerProperties
}
func GetProperties ¶
func GetProperties(cfg vaquita.DynamicConfig, commandName, commandGroup string) *CommandProperties
type Executor ¶
Executor is a main service that knows how to execute commands and handle their errors. Executor must be safe to be accessed by multiple goroutines.
type SemaphoreFactory ¶
type SemaphoreFactory struct {
// contains filtered or unexported fields
}
func NewSemaphoreFactory ¶
func NewSemaphoreFactory() *SemaphoreFactory
Source Files
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Directories
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| Path | Synopsis |
|---|---|
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Port of Hystrix usage example from: https://github.com/Netflix/Hystrix/blob/master/hystrix-examples/src/main/java/com/netflix/hystrix/examples/demo/HystrixCommandDemo.java
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Port of Hystrix usage example from: https://github.com/Netflix/Hystrix/blob/master/hystrix-examples/src/main/java/com/netflix/hystrix/examples/demo/HystrixCommandDemo.java |