diff --git a/CHANGELOG.md b/CHANGELOG.md index 75e6a83b813..5befdf6241c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -8,9 +8,14 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm ## [Unreleased] +### Changed + +- `go.opentelemetry.io/otel/exporters/stdout/stdoutmetric` does not prettifies the output by default anymore. (#4507) + ### Added - Add the "Roll the dice" getting started application example in `go.opentelemetry.io/otel/example/dice`. (#4539) +- The `WithWriter` and `WithPrettyPrint` options to `go.opentelemetry.io/otel/exporters/stdout/stdoutmetric` to set a custom `io.Writer`, and allow displaying the output in human-readable JSON (#4507). ## [1.19.0-rc.1/0.42.0-rc.1] 2023-09-14 diff --git a/exporters/stdout/stdoutmetric/config.go b/exporters/stdout/stdoutmetric/config.go index 6189c019f37..cac5afeeb67 100644 --- a/exporters/stdout/stdoutmetric/config.go +++ b/exporters/stdout/stdoutmetric/config.go @@ -15,6 +15,7 @@ package stdoutmetric // import "go.opentelemetry.io/otel/exporters/stdout/stdout import ( "encoding/json" + "io" "os" "go.opentelemetry.io/otel/sdk/metric" @@ -22,6 +23,7 @@ import ( // config contains options for the exporter. type config struct { + prettyPrint bool encoder *encoderHolder temporalitySelector metric.TemporalitySelector aggregationSelector metric.AggregationSelector @@ -37,10 +39,15 @@ func newConfig(options ...Option) config { if cfg.encoder == nil { enc := json.NewEncoder(os.Stdout) - enc.SetIndent("", "\t") cfg.encoder = &encoderHolder{encoder: enc} } + if cfg.prettyPrint { + if e, ok := cfg.encoder.encoder.(*json.Encoder); ok { + e.SetIndent("", "\t") + } + } + if cfg.temporalitySelector == nil { cfg.temporalitySelector = metric.DefaultTemporalitySelector } @@ -74,6 +81,22 @@ func WithEncoder(encoder Encoder) Option { }) } +// WithWriter sets the export stream destination. +// Using this option overrides any previously set encoder. +func WithWriter(w io.Writer) Option { + return WithEncoder(json.NewEncoder(w)) +} + +// WithPrettyPrint prettifies the emitted output. +// This option only works if the encoder is a *json.Encoder, as is the case +// when using `WithWriter`. +func WithPrettyPrint() Option { + return optionFunc(func(c config) config { + c.prettyPrint = true + return c + }) +} + // WithTemporalitySelector sets the TemporalitySelector the exporter will use // to determine the Temporality of an instrument based on its kind. If this // option is not used, the exporter will use the DefaultTemporalitySelector diff --git a/exporters/stdout/stdoutmetric/exporter_test.go b/exporters/stdout/stdoutmetric/exporter_test.go index 71679d623a1..2dbfe6357a2 100644 --- a/exporters/stdout/stdoutmetric/exporter_test.go +++ b/exporters/stdout/stdoutmetric/exporter_test.go @@ -15,6 +15,7 @@ package stdoutmetric_test // import "go.opentelemetry.io/otel/exporters/stdout/stdoutmetric" import ( + "bytes" "context" "encoding/json" "io" @@ -103,6 +104,43 @@ func deltaSelector(metric.InstrumentKind) metricdata.Temporality { return metricdata.DeltaTemporality } +func TestExportWithOptions(t *testing.T) { + var ( + data = new(metricdata.ResourceMetrics) + ctx = context.Background() + ) + + for _, tt := range []struct { + name string + opts []stdoutmetric.Option + + expectedData string + }{ + { + name: "with no options", + expectedData: "{\"Resource\":null,\"ScopeMetrics\":null}\n", + }, + { + name: "with pretty print", + opts: []stdoutmetric.Option{ + stdoutmetric.WithPrettyPrint(), + }, + expectedData: "{\n\t\"Resource\": null,\n\t\"ScopeMetrics\": null\n}\n", + }, + } { + t.Run(tt.name, func(t *testing.T) { + var b bytes.Buffer + opts := append(tt.opts, stdoutmetric.WithWriter(&b)) + + exp, err := stdoutmetric.New(opts...) + require.NoError(t, err) + require.NoError(t, exp.Export(ctx, data)) + + assert.Equal(t, tt.expectedData, b.String()) + }) + } +} + func TestTemporalitySelector(t *testing.T) { exp, err := stdoutmetric.New( testEncoderOption(),