recorder

Documentation

Overview

Package recorder contains logic to record data into a database. The payload is guaranteed to be json marshallable. Any types that implements the DataRecorder interface can be used in this system.

Important Notes

When the context is cancelled, the recorder should finish its job and return.

Index

• Variables
• type DataRecorder
• type ErrEndpointNotAvailable
  • func (ErrEndpointNotAvailable) EndpointNotAvailable()
  • func (e ErrEndpointNotAvailable) Error() string
• type ErrInvalidEndpoint
  • func (e ErrInvalidEndpoint) Error() string
  • func (ErrInvalidEndpoint) InvalidEndpoint()
• type ErrInvalidIndexName
  • func (e ErrInvalidIndexName) Error() string
  • func (ErrInvalidIndexName) InvalidIndexName()
• type ErrLowBackoffValue
  • func (e ErrLowBackoffValue) Error() string
  • func (ErrLowBackoffValue) LowBackoffValue()
• type ErrParseInterval
  • func (e ErrParseInterval) Error() string
  • func (ErrParseInterval) ParseInterval()
• type ErrParseTimeOut
  • func (e ErrParseTimeOut) Error() string
  • func (ErrParseTimeOut) ParseTimeOut()
• type Job

Examples

• DataRecorder

Variables

var (
	// ErrEmptyName is the error when the package name is empty.
	ErrEmptyName = fmt.Errorf("name cannot be empty")

	// ErrEmptyEndpoint is the error when the given endpoint is empty.
	ErrEmptyEndpoint = fmt.Errorf("endpoint cannot be empty")

	// ErrEmptyIndexName is the error when the index_name is an empty string.
	ErrEmptyIndexName = fmt.Errorf("index_name cannot be empty")

	// ErrBackoffExceeded is the error when the endpoint's absence has exceeded the backoff value.
	// It is not strictly an error, it is however a pointer to an error in the past.
	ErrBackoffExceeded = fmt.Errorf("endpoint gone too long")

	// ErrPingNotCalled is the error if the caller calls the record without pinging.
	ErrPingNotCalled = fmt.Errorf("the caller forgot to ask me pinging")
)

Types

type DataRecorder

type DataRecorder interface {
	// Name should return the representation string for this recorder.
	// Choose a very simple and unique name.
	Name() string

	// Ping should ping the endpoint and return nil if was successful.
	// The Engine will not launch the reader if the ping result is an error.
	Ping() error

	// IndexName comes from the configuration, but the engine takes over.
	IndexName() string

	// Timeout is required by the Engine so it can read the time-outs.
	Timeout() time.Duration

	// The recorder should record the Job and report the errors.
	// When the context is timed-out or cancelled, the recorder should return
	// with the context's error.
	Record(context.Context, *Job) error
}

DataRecorder receives a payload for shipping data to a repository. The repository should have the concept of index/database and type/table abstractions. See ElasticSearch for more information.

Notes

Recorders should not change the index name coming in the payload unless they have a valid reason. The engine might add a date to this index name if the user has specified in the configuration file.

Example

This example shows when a record job is issued, the recorder hits the endpoint.

package main

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"time"

	"github.com/arsham/expvastic/internal/datatype"
	"github.com/arsham/expvastic/recorder"
	"github.com/arsham/expvastic/recorder/testing"
)

func main() {
	ctx := context.Background()
	receivedPayload := make(chan string)
	pinged := false
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if !pinged {
			pinged = true
			return
		}
		receivedPayload <- "I have received the payload!"
	}))
	defer ts.Close()

	rec := testing.GetRecorder(ctx, ts.URL)
	rec.Ping()
	fmt.Println("Pinging successful")
	payload := datatype.New([]datatype.DataType{
		datatype.StringType{Key: "key", Value: "value"},
	})
	job := &recorder.Job{
		Payload:   payload,
		IndexName: "my index",
		Time:      time.Now(),
	}

	go func() {
		err := rec.Record(ctx, job)
		if err != nil {
			panic("Wasn't expecting any errors")
		}
	}()
	fmt.Println(<-receivedPayload)
	fmt.Println("No errors reported")

	go rec.Record(ctx, job) // Issuing another job
	fmt.Println(<-receivedPayload)

}

Output:

Pinging successful
I have received the payload!
No errors reported
I have received the payload!

type ErrEndpointNotAvailable

type ErrEndpointNotAvailable struct {
	Endpoint string
	Err      error
}

ErrEndpointNotAvailable is the error when the endpoint is not available.

func (ErrEndpointNotAvailable) EndpointNotAvailable

func (ErrEndpointNotAvailable) EndpointNotAvailable()

EndpointNotAvailable defines the behaviour of the error

func (ErrEndpointNotAvailable) Error

func (e ErrEndpointNotAvailable) Error() string

type ErrInvalidEndpoint

type ErrInvalidEndpoint string

ErrInvalidEndpoint is the error when the endpoint is not a valid url

func (ErrInvalidEndpoint) Error

func (e ErrInvalidEndpoint) Error() string

func (ErrInvalidEndpoint) InvalidEndpoint

func (ErrInvalidEndpoint) InvalidEndpoint()

InvalidEndpoint defines the behaviour of the error

type ErrInvalidIndexName

type ErrInvalidIndexName string

ErrInvalidIndexName is the error when the index name is invalid.

func (ErrInvalidIndexName) Error

func (e ErrInvalidIndexName) Error() string

func (ErrInvalidIndexName) InvalidIndexName

func (ErrInvalidIndexName) InvalidIndexName()

InvalidIndexName defines the behaviour of the error

type ErrLowBackoffValue

type ErrLowBackoffValue int64

ErrLowBackoffValue is the error when the endpoint is not a valid url

func (ErrLowBackoffValue) Error

func (e ErrLowBackoffValue) Error() string

func (ErrLowBackoffValue) LowBackoffValue

func (ErrLowBackoffValue) LowBackoffValue()

LowBackoffValue defines the behaviour of the error

type ErrParseInterval

type ErrParseInterval struct {
	Interval string
	Err      error
}

ErrParseInterval is for when the timeout cannot be parsed

func (ErrParseInterval) Error

func (e ErrParseInterval) Error() string

func (ErrParseInterval) ParseInterval

func (ErrParseInterval) ParseInterval()

ParseInterval defines the behaviour of the error

type ErrParseTimeOut

type ErrParseTimeOut struct {
	Timeout string
	Err     error
}

ErrParseTimeOut is for when the timeout cannot be parsed

func (ErrParseTimeOut) Error

func (e ErrParseTimeOut) Error() string

func (ErrParseTimeOut) ParseTimeOut

func (ErrParseTimeOut) ParseTimeOut()

ParseTimeOut defines the behaviour of the error

type Job

type Job struct {
	// ID is the job ID generated at the time the payload was generated.
	ID token.ID

	// Payload has a Bytes() method for returning the data.
	// It is guaranteed to be json marshallable.
	Payload datatype.DataContainer

	// Time is the recorded time at the time of fetching data by the readers.
	// You should use this value to fetch the content of the payload
	Time time.Time

	// IndexName might be different than the one is set in the recorder.
	// Engine might decide to change it and you have to use the provided one.
	IndexName string

	// TypeName comes from the configuration of readers.
	TypeName string
}

Job is sent with a context and a payload to be recorded. If the TypeName and IndexName are different than the previous one, the recorder should use the ones engine provides. If any errors occurred, recorders should return the error on Read return value.