interfaces

Code generation tools for Go’s interfaces.

Tools available in this repository:

• cmd/interfacer
• cmd/structer

cmd/interfacer

Generates an interface for a named type.

Installation

~ $ go install github.com/rjeczalik/interfaces/cmd/interfacer@latest

Usage

~ $ interfacer -help

Usage of interfacer:
  -all
        Include also unexported methods.
  -as string
        Generated interface name. (default "main.Interface")
  -for string
        Type to generate an interface for.
  -o string
        Output file. (default "-")

Example

• generate by manually

  ~ $ interfacer -for os.File -as mock.File

• generate by go generate

  //go:generate interfacer -for os.File -as mock.File -o file_iface.go

  ~ $ go generate  ./...

• output
  ```go
  // Created by interfacer; DO NOT EDIT

package mock

import (
“os”
)

// File is an interface generated for “os”.File.
type File interface {
Chdir() error
Chmod(os.FileMode) error
Chown(int, int) error
Close() error
Fd() uintptr
Name() string
Read([]byte) (int, error)
ReadAt([]byte, int64) (int, error)
Readdir(int) ([]os.FileInfo, error)
Readdirnames(int) ([]string, error)
Seek(int64, int) (int64, error)
Stat() (os.FileInfo, error)
Sync() error
Truncate(int64) error
Write([]byte) (int, error)
WriteAt([]byte, int64) (int, error)
WriteString(string) (int, error)
}

### cmd/structer [![GoDoc](https://godoc.org/github.com/rjeczalik/interfaces/cmd/structer?status.png)](https://godoc.org/github.com/rjeczalik/interfaces/cmd/structer)
Generates a struct for a formatted file. Currently supported formats are:
- CSV
*Installation*
```bash
~ $ go get github.com/rjeczalik/interfaces/cmd/structer

Usage

~ $ structer -help

Usage of structer:
  -as string
        Generated struct name. (default "main.Struct")
  -f string
        Input file. (default "-")
  -o string
        Output file. (default "-")
  -tag string
        Name for a struct tag to add to each field.
  -type string
        Type of the input, overwrites inferred from file name.

Example

~ $ head -2 aws-billing.csv         # first line is a CSV header, second - first line of values

"InvoiceID","PayerAccountId","LinkedAccountId","RecordType","RecordID","BillingPeriodStartDate","BillingPeriodEndDate","InvoiceDate"
"Estimated","123456","","PayerLineItem","5433212345","2016/01/01 00:00:00","2016/01/31 23:59:59","2016/01/21 19:19:06"

~ $ structer -f aws-billing.csv -tag json -as billing.Record

// Created by structer; DO NOT EDIT
package billing
import (
        "strconv"
        "time"
)
// Record is a struct generated from "aws-billing.csv" file.
type Record struct {
        InvoiceID              string    `json:"invoiceID"`
        PayerAccountID         int64     `json:"payerAccountID"`
        LinkedAccountID        string    `json:"linkedAccountID"`
        RecordType             string    `json:"recordType"`
        RecordID               int64     `json:"recordID"`
        BillingPeriodStartDate time.Time `json:"billingPeriodStartDate"`
        BillingPeriodEndDate   time.Time `json:"billingPeriodEndDate"`
        InvoiceDate            time.Time `json:"invoiceDate"`
}
// MarshalCSV encodes r as a single CSV record.
func (r *Record) MarshalCSV() ([]string, error) {
        records := []string{
                r.InvoiceID,
                strconv.FormatInt(r.PayerAccountID, 10),
                r.LinkedAccountID,
                r.RecordType,
                strconv.FormatInt(r.RecordID, 10),
                time.Parse("2006/01/02 15:04:05", r.BillingPeriodStartDate),
                time.Parse("2006/01/02 15:04:05", r.BillingPeriodEndDate),
                time.Parse("2006/01/02 15:04:05", r.InvoiceDate),
        }
        return records, nil
}
// UnmarshalCSV decodes a single CSV record into r.
func (r *Record) UnmarshalCSV(record []string) error {
        if len(record) != 8 {
                return fmt.Errorf("invalud number fields: want 8, got %d", len(record))
        }
        r.InvoiceID = record[0]
        if record[1] != "" {
                if val, err := strconv.ParseInt(record[1], 10, 64); err == nil {
                        r.PayerAccountID = val
                } else {
                        return err
                }
        }
        r.LinkedAccountID = record[2]
        r.RecordType = record[3]
        if record[4] != "" {
                if val, err := strconv.ParseInt(record[4], 10, 64); err == nil {
                        r.RecordID = val
                } else {
                        return err
                }
        }
        if record[5] != "" {
                if val, err := time.Parse("2006/01/02 15:04:05", record[5]); err == nil {
                        r.BillingPeriodStartDate = val
                } else {
                        return err
                }
        }
        if record[6] != "" {
                if val, err := time.Parse("2006/01/02 15:04:05", record[6]); err == nil {
                        r.BillingPeriodEndDate = val
                } else {
                        return err
                }
        }
        if record[7] != "" {
                if val, err := time.Parse("2006/01/02 15:04:05", record[7]); err == nil {
                        r.InvoiceDate = val
                } else {
                        return err
                }
        }
        return nil
}