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Include the contents of logs when postgres fails to start or initdb f…
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…ails (#84)

* fix: print log contents when postgres fails to start

* fix: flush the logger before attempting to read

* test: failure is included in error when postgres fails to start

* fix: include log contents with initialization errors

* fix: flush the logger before reading

* refactor: read by file name

* test: logs are output on initialization failure

* fix: os -> ioutil for older versions of Go

* fix: os -> ioutil for older versions of Go

* lint: stop cuddling 😆

* fix: bail if we can't read the logs after 10s

* refactor: move log reading into function

* refactor: use timeout version for startPostgres too

* test: logging method

* test: error case

* test: logging method content

* fix: imports

* feat: include log reading error in log output
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mackinleysmith committed Feb 25, 2023
1 parent 6dade9d commit 9c9e366
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Showing 6 changed files with 76 additions and 4 deletions.
5 changes: 4 additions & 1 deletion embedded_postgres.go
Original file line number Diff line number Diff line change
Expand Up @@ -188,7 +188,10 @@ func startPostgres(ep *EmbeddedPostgres) error {
postgresProcess.Stderr = ep.syncedLogger.file

if err := postgresProcess.Run(); err != nil {
return fmt.Errorf("could not start postgres using %s", postgresProcess.String())
_ = ep.syncedLogger.flush()
logContent, _ := readLogsOrTimeout(ep.syncedLogger.file)

return fmt.Errorf("could not start postgres using %s:\n%s", postgresProcess.String(), string(logContent))
}

return nil
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3 changes: 2 additions & 1 deletion embedded_postgres_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -226,12 +226,13 @@ func Test_ErrorWhenCannotStartPostgresProcess(t *testing.T) {
}

database.initDatabase = func(binaryExtractLocation, runtimePath, dataLocation, username, password, locale string, logger *os.File) error {
_, _ = logger.Write([]byte("ah it did not work"))
return nil
}

err = database.Start()

assert.EqualError(t, err, fmt.Sprintf(`could not start postgres using %s/bin/pg_ctl start -w -D %s/data -o "-p 5432"`, extractPath, extractPath))
assert.EqualError(t, err, fmt.Sprintf("could not start postgres using %s/bin/pg_ctl start -w -D %s/data -o \"-p 5432\":\nah it did not work", extractPath, extractPath))
}

func Test_CustomConfig(t *testing.T) {
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26 changes: 26 additions & 0 deletions logging.go
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,9 @@ package embeddedpostgres
import (
"fmt"
"io"
"io/ioutil"
"os"
"time"
)

type syncedLogger struct {
Expand Down Expand Up @@ -53,3 +55,27 @@ func (s *syncedLogger) flush() error {

return nil
}

func readLogsOrTimeout(logger *os.File) (logContent []byte, err error) {
logContent = []byte("logs could not be read")

logContentChan := make(chan []byte, 1)
errChan := make(chan error, 1)

go func() {
if actualLogContent, err := ioutil.ReadFile(logger.Name()); err == nil {
logContentChan <- actualLogContent
} else {
errChan <- err
}
}()

select {
case logContent = <-logContentChan:
case err = <-errChan:
case <-time.After(10 * time.Second):
err = fmt.Errorf("timed out waiting for logs")
}

return logContent, err
}
25 changes: 25 additions & 0 deletions logging_test.go
Original file line number Diff line number Diff line change
@@ -1,10 +1,13 @@
package embeddedpostgres

import (
"fmt"
"io/ioutil"
"os"
"testing"

"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)

type customLogger struct {
Expand Down Expand Up @@ -56,3 +59,25 @@ func Test_SyncedLogger_NoErrorDuringFlush(t *testing.T) {

assert.Equal(t, "some logs\non a new line", string(logger.logLines))
}

func Test_readLogsOrTimeout(t *testing.T) {
logFile, err := ioutil.TempFile("", "prepare_database_test_log")
if err != nil {
panic(err)
}

logContent, err := readLogsOrTimeout(logFile)
assert.NoError(t, err)
assert.Equal(t, []byte(""), logContent)

_, _ = logFile.Write([]byte("and here are the logs!"))

logContent, err = readLogsOrTimeout(logFile)
assert.NoError(t, err)
assert.Equal(t, []byte("and here are the logs!"), logContent)

require.NoError(t, os.Remove(logFile.Name()))
logContent, err = readLogsOrTimeout(logFile)
assert.Equal(t, []byte("logs could not be read"), logContent)
assert.EqualError(t, err, fmt.Sprintf("open %s: no such file or directory", logFile.Name()))
}
6 changes: 5 additions & 1 deletion prepare_database.go
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,11 @@ func defaultInitDatabase(binaryExtractLocation, runtimePath, pgDataDir, username
postgresInitDBProcess.Stdout = logger

if err = postgresInitDBProcess.Run(); err != nil {
return fmt.Errorf("unable to init database using '%s': %w", postgresInitDBProcess.String(), err)
logContent, readLogsErr := readLogsOrTimeout(logger) // we want to preserve the original error
if readLogsErr != nil {
logContent = []byte(string(logContent) + " - " + readLogsErr.Error())
}
return fmt.Errorf("unable to init database using '%s': %w\n%s", postgresInitDBProcess.String(), err, string(logContent))
}

if err = os.Remove(passwordFile); err != nil {
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15 changes: 14 additions & 1 deletion prepare_database_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ package embeddedpostgres
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"testing"
Expand All @@ -27,6 +28,11 @@ func Test_defaultInitDatabase_ErrorWhenCannotStartInitDBProcess(t *testing.T) {
panic(err)
}

logFile, err := ioutil.TempFile("", "prepare_database_test_log")
if err != nil {
panic(err)
}

defer func() {
if err := os.RemoveAll(binTempDir); err != nil {
panic(err)
Expand All @@ -35,15 +41,22 @@ func Test_defaultInitDatabase_ErrorWhenCannotStartInitDBProcess(t *testing.T) {
if err := os.RemoveAll(runtimeTempDir); err != nil {
panic(err)
}

if err := os.Remove(logFile.Name()); err != nil {
panic(err)
}
}()

err = defaultInitDatabase(binTempDir, runtimeTempDir, filepath.Join(runtimeTempDir, "data"), "Tom", "Beer", "", os.Stderr)
_, _ = logFile.Write([]byte("and here are the logs!"))

err = defaultInitDatabase(binTempDir, runtimeTempDir, filepath.Join(runtimeTempDir, "data"), "Tom", "Beer", "", logFile)

assert.NotNil(t, err)
assert.Contains(t, err.Error(), fmt.Sprintf("unable to init database using '%s/bin/initdb -A password -U Tom -D %s/data --pwfile=%s/pwfile'",
binTempDir,
runtimeTempDir,
runtimeTempDir))
assert.Contains(t, err.Error(), "and here are the logs!")
assert.FileExists(t, filepath.Join(runtimeTempDir, "pwfile"))
}

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