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README
¶
dbtools
This library has a few helpers for using in production code and
go-sqlmock tests. There is also a Mocha inspired reporter for
spec BDD library.
Transaction
WithTransaction
WithTransaction helps you reduce the amount of code you put in the logic by
taking care of errors. For example instead of writing:
tx, err := db.Begin()
if err != nil {
return errors.Wrap(err, "starting transaction")
}
err := firstQueryCall(tx)
if err != nil {
e := errors.Wrap(tx.Rollback(), "rolling back transaction")
return multierror.Append(err, e).ErrorOrNil()
}
err := secondQueryCall(tx)
if err != nil {
e := errors.Wrap(tx.Rollback(), "rolling back transaction")
return multierror.Append(err, e).ErrorOrNil()
}
err := thirdQueryCall(tx)
if err != nil {
e := errors.Wrap(tx.Rollback(), "rolling back transaction")
return multierror.Append(err, e).ErrorOrNil()
}
return errors.Wrap(tx.Commit(), "committing transaction")
You can write:
return dbtools.WithTransaction(db, firstQueryCall, secondQueryCall, thirdQueryCall)
Function types should be of func(*sql.Tx) error.
Retry
Retry calls your function, and if it errors it calls it again with a delay.
Every time the function returns an error it increases the delay. Eventually it
returns the last error or nil if one call is successful.
You can use this function in non-database situations too.
dbtools.Retry(10, time.Second. func(i int) error {
logger.Debugf("%d iteration", i)
return myFunctionCall()
})
RetryTransaction
RetryTransaction is a combination of WithTransaction and Retry. It stops
the retry if the context is cancelled/done.
err := dbtools.RetryTransaction(ctx, db, 10, time.Millisecond * 10,
firstQueryCall,
secondQueryCall,
thirdQueryCall,
)
// error check
Spec Reports
Mocha is a reporter for printing Mocha inspired reports when using
spec BDD library.
Usage
import "github.com/arsham/dbtools/dbtesting"
func TestFoo(t *testing.T) {
spec.Run(t, "Foo", func(t *testing.T, when spec.G, it spec.S) {
// ...
}, spec.Report(&dbtesting.Mocha{}))
}
You can set an io.Writer to Mocha.Out to redirect the output, otherwise it
prints to the os.Stdout.
SQLMock Helpers
There a couple of helpers for using with go-sqlmock test cases for cases that values are random but it is important to check the values passed in queries.
ValueRecorder
If you have an value and use it in multiple queries, and you want to
make sure the queries are passed with correct values, you can use the
ValueRecorder. For example UUIDs, time and random values.
For instance if the first query generates a random number but it is essential to use the same value on next queries:
import "database/sql"
func TestFoo(t *testing.T) {
// ...
// assume num has been generated randomly
num := 666
_, err := tx.ExecContext(ctx, "INSERT INTO life (value) VALUE ($1)", num)
// error check
_, err = tx.ExecContext(ctx, "INSERT INTO reality (value) VALUE ($1)", num)
// error check
_, err = tx.ExecContext(ctx, "INSERT INTO everywhere (value) VALUE ($1)", num)
// error check
}
Your tests can be checked easily like this:
import (
"github.com/arsham/dbtools/dbtesting"
"github.com/DATA-DOG/go-sqlmock"
)
func TestFoo(t *testing.T) {
// ...
rec := dbtesting.NewValueRecorder()
mock.ExpectExec("INSERT INTO life .+").
WithArgs(rec.Record("truth")).
WillReturnResult(sqlmock.NewResult(1, 1))
mock.ExpectExec("INSERT INTO reality .+").
WithArgs(rec.For("truth")).
WillReturnResult(sqlmock.NewResult(1, 1))
mock.ExpectExec("INSERT INTO everywhere .+").
WithArgs(rec.For("truth")).
WillReturnResult(sqlmock.NewResult(1, 1))
}
Recorded values can be retrieved by casting to their types:
rec.Value("true").(string)
There are two rules for using the ValueRecorder:
- You can only record for a value once.
- You should record a value before you call
FororValue.
It will panic if these requirements are not met.
OkValue
If you are only interested in checking some arguments passed to the Exec/Query
functions and you don't want to check everything (maybe because thy are not
relevant to the current test), you can use OkValue.
import (
"github.com/arsham/dbtools/dbtesting"
"github.com/DATA-DOG/go-sqlmock"
)
ok := dbtesting.OkValue
mock.ExpectExec("INSERT INTO life .+").
WithArgs(
ok,
ok,
ok,
"important value"
ok,
ok,
ok,
)
Testing
To run the tests:
make
test_race target runs tests with -race flag. third-party installs
reflex task runner.
License
Use of this source code is governed by the Apache 2.0 license. License can be found in the LICENSE file.
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Retry ¶
Retry calls fn for retries times until it returns nil. If retries is zero fn would not be called. It delays and retries if the function returns any errors. The fn function receives the current iteration as its argument.
Example ¶
package main
import (
"fmt"
"time"
"github.com/arsham/dbtools"
"github.com/pkg/errors"
)
func main() {
err := dbtools.Retry(100, time.Nanosecond, func(i int) error {
fmt.Printf("Running iteration %d.\n", i+1)
if i < 1 {
return errors.New("ignored error")
}
return nil
})
fmt.Println("Error:", err)
}
Output: Running iteration 1. Running iteration 2. Error: <nil>
Example (Two) ¶
package main
import (
"fmt"
"time"
"github.com/arsham/dbtools"
"github.com/pkg/errors"
)
func main() {
err := dbtools.Retry(2, time.Nanosecond, func(i int) error {
fmt.Printf("Running iteration %d.\n", i+1)
return errors.New("some error")
})
fmt.Println("Error:", err)
}
Output: Running iteration 1. Running iteration 2. Error: some error
func RetryTransaction ¶
func RetryTransaction(ctx context.Context, db *sql.DB, retries int, delay time.Duration, fn ...func(*sql.Tx) error) error
RetryTransaction combines WithTransaction and Retry calls. It stops the call if context is times out or cancelled.
Example ¶
// For this example we are using sqlmock, but you can use an actual
// connection with this function.
db, mock, err := sqlmock.New()
if err != nil {
panic(err)
}
defer db.Close()
defer func() {
if err := mock.ExpectationsWereMet(); err != nil {
fmt.Printf("there were unfulfilled expectations: %s\n", err)
}
}()
mock.ExpectBegin()
mock.ExpectRollback()
mock.ExpectBegin()
mock.ExpectRollback()
mock.ExpectBegin()
mock.ExpectCommit()
calls := 0
ctx := context.Background()
err = dbtools.RetryTransaction(ctx, db, 100, time.Millisecond*100, func(*sql.Tx) error {
calls++
fmt.Printf("Running iteration %d.\n", calls)
if calls < 3 {
return errors.New("some error")
}
return nil
})
fmt.Println("Error:", err)
Output: Running iteration 1. Running iteration 2. Running iteration 3. Error: <nil>
func WithTransaction ¶
WithTransaction creates a transaction on db and uses it to call fn functions one by one. The first function that returns an error will cause the loop to stop and transaction to be rolled back.
Example ¶
// For this example we are using sqlmock, but you can use an actual
// connection with this function.
db, mock, err := sqlmock.New()
if err != nil {
panic(err)
}
defer db.Close()
defer func() {
if err := mock.ExpectationsWereMet(); err != nil {
fmt.Printf("there were unfulfilled expectations: %s\n", err)
}
}()
mock.ExpectBegin()
mock.ExpectCommit()
err = dbtools.WithTransaction(db, func(*sql.Tx) error {
fmt.Println("Running first query.")
return nil
}, func(*sql.Tx) error {
fmt.Println("Running second query.")
return nil
})
fmt.Println("Transaction has an error:", err != nil)
Output: Running first query. Running second query. Transaction has an error: false
Example (Two) ¶
// For this example we are using sqlmock, but you can use an actual
// connection with this function.
db, mock, err := sqlmock.New()
if err != nil {
panic(err)
}
defer db.Close()
defer func() {
if err := mock.ExpectationsWereMet(); err != nil {
fmt.Printf("there were unfulfilled expectations: %s\n", err)
}
}()
mock.ExpectBegin()
mock.ExpectRollback()
err = dbtools.WithTransaction(db, func(*sql.Tx) error {
fmt.Println("Running first query.")
return nil
}, func(*sql.Tx) error {
fmt.Println("Running second query.")
return errors.New("something happened")
}, func(*sql.Tx) error {
fmt.Println("Running third query.")
return nil
})
fmt.Println("Transaction has an error:", err != nil)
Output: Running first query. Running second query. Transaction has an error: true
Types ¶
This section is empty.
Source Files
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