middlewares

README

Middlewares

Some common middlewares I use in multiple projects

Contains:

• Gzip: gzips responses
• Audit: go-metric capturing with yammer metrics compatible output
• Healthchecks: go-metrics healthchecks with yammer metrics compatible output
• Profiling: use pprof
• Recovery: handle panics

Documentation

Index

• Constants
• func DefaultStack(appInfo AppInfo, lgr Logger, orig http.Handler) http.Handler
• func Gzip(level int, next http.Handler) http.Handler
• func GzipMW(level int) alice.Constructor
• func NewAuditMW(info AppInfo, logger Logger) alice.Constructor
• func NewHealthChecksMW(basePath string) alice.Constructor
• func NewProfiler(next http.Handler) http.Handler
• func NewRecoveryMW(appName string, lgr Logger) alice.Constructor
• type AppInfo
• type Audit
  • func NewAudit(info AppInfo, logger Logger, next http.Handler) *Audit
  • func (l *Audit) ServeHTTP(rw http.ResponseWriter, r *http.Request)
• type CounterMetric
• type GaugeFloat64Metric
• type GaugeMetric
• type HealtCheckData
• type HealthChecks
  • func NewHealthChecks(basePath string, next http.Handler) *HealthChecks
  • func (h *HealthChecks) ServeHTTP(rw http.ResponseWriter, r *http.Request)
• type HistogramMetric
• type Logger
• type MeterMetric
• type Profiler
  • func (p *Profiler) ServeHTTP(rw http.ResponseWriter, r *http.Request)
• type Recovery
  • func NewRecovery(appName string, lgr Logger, next http.Handler) *Recovery
  • func (rec *Recovery) ServeHTTP(rw http.ResponseWriter, r *http.Request)
• type TimerMetric

Constants

const (
	BestCompression    = gzip.BestCompression
	BestSpeed          = gzip.BestSpeed
	DefaultCompression = gzip.DefaultCompression
	NoCompression      = gzip.NoCompression
)

These compression constants are copied from the compress/gzip package.

Functions

func DefaultStack

func DefaultStack(appInfo AppInfo, lgr Logger, orig http.Handler) http.Handler

DefaultStack sets up the default middlewares

func Gzip

func Gzip(level int, next http.Handler) http.Handler

Gzip returns a handler which will handle the Gzip compression in ServeHTTP. Valid values for level are identical to those in the compress/gzip package.

func GzipMW

func GzipMW(level int) alice.Constructor

GzipMW returns a middleware which will handle the Gzip compression in ServeHTTP. Valid values for level are identical to those in the compress/gzip package.

func NewAuditMW

func NewAuditMW(info AppInfo, logger Logger) alice.Constructor

NewAuditMW returns a new Audit middleware

func NewHealthChecksMW

func NewHealthChecksMW(basePath string) alice.Constructor

NewHealthChecksMW creates a new health check middleware at the specified path

func NewProfiler

func NewProfiler(next http.Handler) http.Handler

NewProfiler creates a middleware for profiling

func NewRecoveryMW

func NewRecoveryMW(appName string, lgr Logger) alice.Constructor

NewRecoveryMW returns a new instance of Recovery middleware which traps panics

Types

type AppInfo

type AppInfo struct {
	Name     string `json:"name"`
	Version  string `json:"version"`
	Commit   string `json:"commit"`
	BasePath string `json:"basePath"`
	Pid      int    `json:"pid"`
}

AppInfo the information describing the component for this API

type Audit

type Audit struct {
	// logger is the Logger instance used to log messages with the Audit middleware
	Logger Logger
	// contains filtered or unexported fields
}

Audit is a middleware handler that logs the request as it goes in and the response as it goes out.

func NewAudit

func NewAudit(info AppInfo, logger Logger, next http.Handler) *Audit

NewAudit returns a new Audit instance

func (*Audit) ServeHTTP

func (l *Audit) ServeHTTP(rw http.ResponseWriter, r *http.Request)

type CounterMetric

type CounterMetric struct {
	Count int64 `json:"count"`
}

CounterMetric represents a value that increases or decreases

type GaugeFloat64Metric

type GaugeFloat64Metric struct {
	Value float64 `json:"value"`
}

GaugeFloat64Metric represents a float64 measurement

type GaugeMetric

type GaugeMetric struct {
	Value int64 `json:"value"`
}

GaugeMetric represents measurements.

type HealtCheckData

type HealtCheckData struct {
	Error string `json:"error"`
}

HealtCheckData shows error status if any for a health check

type HealthChecks

type HealthChecks struct {
	// contains filtered or unexported fields
}

HealthChecks is a middleware that serves healthcheck information

func NewHealthChecks

func NewHealthChecks(basePath string, next http.Handler) *HealthChecks

NewHealthChecks creates a new health check middleware at the specified path

func (*HealthChecks) ServeHTTP

func (h *HealthChecks) ServeHTTP(rw http.ResponseWriter, r *http.Request)

ServeHTTP is the middleware interface implementation

type HistogramMetric

type HistogramMetric struct {
	Count  int64   `json:"count"`
	Min    int64   `json:"min"`
	Max    int64   `json:"max"`
	Mean   float64 `json:"mean"`
	StdDev float64 `json:"stdDev"`
	Median float64 `json:"median"`
	P75    float64 `json:"p75"`
	P95    float64 `json:"p95"`
	P99    float64 `json:"p99"`
	P999   float64 `json:"p999"`
	Unit   string  `json:"unit,omitempty"`
}

HistogramMetric shows a histogram metric

type Logger

type Logger interface {
	Debugf(string, ...interface{})
	Infof(string, ...interface{})
	Errorf(string, ...interface{})
}

Logger interface to allow different logging libaries to be used with this middleware

type MeterMetric

type MeterMetric struct {
	Count int64   `json:"count"`
	M1    float64 `json:"m1"`
	M5    float64 `json:"m5"`
	M15   float64 `json:"m15"`
	Mean  float64 `json:"mean"`
}

MeterMetric represents a metered value with 1-minute, 5-minute and 15 minute averages as well as a mean

type Profiler

type Profiler struct {
	// contains filtered or unexported fields
}

Profiler exposes net/http/pprof as a middleware

func (*Profiler) ServeHTTP

func (p *Profiler) ServeHTTP(rw http.ResponseWriter, r *http.Request)

type Recovery

type Recovery struct {
	Logger     Logger
	PrintStack bool
	// contains filtered or unexported fields
}

Recovery is a middleware that recovers from any panics and writes a 500 if there was one.

func NewRecovery

func NewRecovery(appName string, lgr Logger, next http.Handler) *Recovery

NewRecovery returns a new instance of Recovery

func (*Recovery) ServeHTTP

func (rec *Recovery) ServeHTTP(rw http.ResponseWriter, r *http.Request)

type TimerMetric

type TimerMetric struct {
	Rate     MeterMetric     `json:"rate"`
	Duration HistogramMetric `json:"duration"`
}

TimerMetric is a combination of a meter metric and a histogram metric, typically used for tracing time spent and call counts for example