expvar

Documentation

Overview

Package expvar contains logic to read from an expvar provide. The data comes in JSON format. The GC and memory related information will be changed to better presented to the data recorders. Bytes will be turned into megabytes, gc lists will be truncated to remove zero values.

Index

• type Conf
  • func WithLogger(log tools.FieldLogger) Conf
  • func WithMapFile(mapFile string) Conf
  • func WithViper(v unmarshaller, name, key string) Conf
• type Config
  • func NewConfig(conf ...Conf) (*Config, error)
  • func (c *Config) Backoff() int
  • func (c *Config) Endpoint() string
  • func (c *Config) Interval() time.Duration
  • func (c *Config) Logger() tools.FieldLogger
  • func (c *Config) Mapper() datatype.Mapper
  • func (c *Config) Name() string
  • func (c *Config) Reader() (reader.DataReader, error)
  • func (c *Config) Timeout() time.Duration
  • func (c *Config) TypeName() string
• type Reader
  • func New(options ...func(reader.Constructor) error) (*Reader, error)
  • func (r *Reader) Backoff() int
  • func (r *Reader) Endpoint() string
  • func (r *Reader) Interval() time.Duration
  • func (r *Reader) Mapper() datatype.Mapper
  • func (r *Reader) Name() string
  • func (r *Reader) Ping() error
  • func (r *Reader) Read(job *token.Context) (*reader.Result, error)
  • func (r *Reader) SetBackoff(backoff int)
  • func (r *Reader) SetEndpoint(endpoint string)
  • func (r *Reader) SetInterval(interval time.Duration)
  • func (r *Reader) SetLogger(log tools.FieldLogger)
  • func (r *Reader) SetMapper(mapper datatype.Mapper)
  • func (r *Reader) SetName(name string)
  • func (r *Reader) SetTimeout(timeout time.Duration)
  • func (r *Reader) SetTypeName(typeName string)
  • func (r *Reader) Timeout() time.Duration
  • func (r *Reader) TypeName() string

Types

type Conf

type Conf func(*Config) error

Conf func is used for initializing a Config object.

func WithLogger

func WithLogger(log tools.FieldLogger) Conf

WithLogger produces an error if the log is nil.

func WithMapFile

func WithMapFile(mapFile string) Conf

WithMapFile returns any errors on reading the file. If the mapFile is empty, it does nothing and returns nil.

func WithViper

func WithViper(v unmarshaller, name, key string) Conf

WithViper produces an error any of the inputs are empty.

type Config

type Config struct {
	EXPTypeName  string `mapstructure:"type_name"`
	EXPEndpoint  string `mapstructure:"endpoint"`
	EXPInterval  string `mapstructure:"interval"`
	EXPTimeout   string `mapstructure:"timeout"`
	EXPBackoff   int    `mapstructure:"backoff"`
	MapFile      string `mapstructure:"map_file"`
	EXPName      string
	ConfInterval time.Duration
	ConfTimeout  time.Duration
	// contains filtered or unexported fields
}

Config holds the necessary configuration for setting up an expvar reader endpoint. If MapFile is provided, the data will be mapped, otherwise it uses the DefaultMapper.

func NewConfig

func NewConfig(conf ...Conf) (*Config, error)

NewConfig returns an instance of the expvar reader.

func (*Config) Backoff

func (c *Config) Backoff() int

Backoff returns backoff from the config file.

func (*Config) Endpoint

func (c *Config) Endpoint() string

Endpoint returns endpoint from the config file.

func (*Config) Interval

func (c *Config) Interval() time.Duration

Interval returns interval after reading from the config file.

func (*Config) Logger

func (c *Config) Logger() tools.FieldLogger

Logger returns logger.

func (*Config) Mapper

func (c *Config) Mapper() datatype.Mapper

Mapper returns the mapper assigned to this object.

func (*Config) Name

func (c *Config) Name() string

Name returns name from the config file.

func (*Config) Reader

func (c *Config) Reader() (reader.DataReader, error)

Reader implements the ReaderConf interface.

func (*Config) Timeout

func (c *Config) Timeout() time.Duration

Timeout returns timeout after reading from the config file.

func (*Config) TypeName

func (c *Config) TypeName() string

TypeName returns type name from the config file.

type Reader

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

Reader can read from any application that exposes expvar information. It implements DataReader interface.

func New

func New(options ...func(reader.Constructor) error) (*Reader, error)

New generates the Reader based on the provided options. It returns and error on the following occasions:

+------------------+----------------------+
|    Condition     |        Error         |
+------------------+----------------------+
| name == ""       | ErrEmptyName         |
| endpoint == ""   | ErrEmptyEndpoint     |
| Invalid endpoint | InvalidEndpointError |
| typeName == ""   | ErrEmptyTypeName     |
| backoff < 5      | LowBackoffValueError |
+------------------+----------------------+

func (*Reader) Backoff

func (r *Reader) Backoff() int

Backoff returns the backoff.

func (*Reader) Endpoint

func (r *Reader) Endpoint() string

Endpoint returns the endpoint.

func (*Reader) Interval

func (r *Reader) Interval() time.Duration

Interval returns the interval.

func (*Reader) Mapper

func (r *Reader) Mapper() datatype.Mapper

Mapper returns the mapper object.

func (*Reader) Name

func (r *Reader) Name() string

Name shows the name identifier for this reader.

func (*Reader) Ping

func (r *Reader) Ping() error

Ping pings the endpoint and return nil if was successful. It returns an EndpointNotAvailableError if the endpoint id unavailable.

func (*Reader) Read

func (r *Reader) Read(job *token.Context) (*reader.Result, error)

Read begins reading from the target. It returns an error back to the engine if it can't read from metrics provider, Ping() is not called or the endpoint has been unresponsive too many times.

func (*Reader) SetBackoff

func (r *Reader) SetBackoff(backoff int)

SetBackoff sets the backoff of the reader.

func (*Reader) SetEndpoint

func (r *Reader) SetEndpoint(endpoint string)

SetEndpoint sets the endpoint of the reader.

func (*Reader) SetInterval

func (r *Reader) SetInterval(interval time.Duration)

SetInterval sets the interval of the reader.

func (*Reader) SetLogger

func (r *Reader) SetLogger(log tools.FieldLogger)

SetLogger sets the log of the reader.

func (*Reader) SetMapper

func (r *Reader) SetMapper(mapper datatype.Mapper)

SetMapper sets the mapper of the reader.

func (*Reader) SetName

func (r *Reader) SetName(name string)

SetName sets the name of the reader.

func (*Reader) SetTimeout

func (r *Reader) SetTimeout(timeout time.Duration)

SetTimeout sets the timeout of the reader.

func (*Reader) SetTypeName

func (r *Reader) SetTypeName(typeName string)

SetTypeName sets the type name of the reader.

func (*Reader) Timeout

func (r *Reader) Timeout() time.Duration

Timeout returns the time-out.

func (*Reader) TypeName

func (r *Reader) TypeName() string

TypeName shows the typeName the recorder should record as.