tflogtest

Documentation

Overview

Package tflogtest provides functionality for unit testing of provider logging.

Index

• func MultilineJSONDecode(data io.Reader) ([]map[string]interface{}, error)
• func RootLogger(ctx context.Context, output io.Writer) context.Context

Examples

• MultilineJSONDecode
• RootLogger

Functions

func MultilineJSONDecode

func MultilineJSONDecode(data io.Reader) ([]map[string]interface{}, error)

MultilineJSONDecode supports decoding the output of a JSON logger into a slice of maps, with each element representing a log entry.

Example

var output bytes.Buffer

ctx := RootLogger(context.Background(), &output)

// Root provider logger is now available for usage, such as writing
// entries, calling SetField(), or calling NewSubsystem().
tflog.Trace(ctx, "entry 1")
tflog.Trace(ctx, "entry 2")

entries, err := MultilineJSONDecode(&output)

if err != nil {
	// Typical unit testing would call t.Fatalf() here.
	fmt.Printf("unable to read multiple line JSON: %s", err)
}

// Entries can be checked via go-cmp's cmp.Diff() or other testing methods.
// This example outputs them to stdout in an explicitly formatted string,
// which would not be expected in typical unit testing.
for _, entry := range entries {
	fmt.Printf("@message: %s\n", entry["@message"])
}

Output:

@message: entry 1
@message: entry 2

func RootLogger

func RootLogger(ctx context.Context, output io.Writer) context.Context

RootLogger returns a context containing a provider root logger suitable for unit testing that is:

• Written to the given io.Writer, such as a bytes.Buffer.
• Written with JSON output, that can be decoded with MultilineJSONDecode.
• Log level set to TRACE.
• Without location/caller information in log entries.
• Without timestamps in log entries.

Example

var output bytes.Buffer

ctx := RootLogger(context.Background(), &output)

// Root provider logger is now available for usage, such as writing
// entries, calling SetField(), or calling NewSubsystem().
tflog.Trace(ctx, "hello, world", map[string]interface{}{
	"foo":    123,
	"colors": []string{"red", "blue", "green"},
})

fmt.Println(output.String())

Output:

{"@level":"trace","@message":"hello, world","@module":"provider","colors":["red","blue","green"],"foo":123}