feat(profiler): switch to zstd compression by default (#3970)

Author: felixge

profiler/compression.go

@@ -45,7 +45,7 @@ func legacyCompressionStrategy(pt ProfileType, isDelta bool) (compression, compr
 }
 
 func compressionStrategy(pt ProfileType, isDelta bool, config string) (compression, compression) {
-	if config == "" {
+	if config == "" || config == "legacy" {
 		return legacyCompressionStrategy(pt, isDelta)
 	}
 	algorithm, levelStr, _ := strings.Cut(config, "-")

profiler/options.go

@@ -6,6 +6,7 @@
 package profiler
 
 import (
+	"cmp"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -187,7 +188,7 @@ func defaultConfig() (*config, error) {
 		deltaProfiles:        internal.BoolEnv("DD_PROFILING_DELTA", true),
 		logStartup:           internal.BoolEnv("DD_TRACE_STARTUP_LOGS", true),
 		endpointCountEnabled: internal.BoolEnv(traceprof.EndpointCountEnvVar, false),
-		compressionConfig:    env.Get("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS"),
+		compressionConfig:    cmp.Or(env.Get("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS"), "zstd"),
 		traceConfig: executionTraceConfig{
 			Enabled: internal.BoolEnv("DD_PROFILING_EXECUTION_TRACE_ENABLED", executionTraceEnabledDefault),
 			Period:  internal.DurationEnv("DD_PROFILING_EXECUTION_TRACE_PERIOD", 15*time.Minute),

profiler/profile_test.go

@@ -109,6 +109,7 @@ main;bar 0 0 8 16
 		},
 	}
 
+	t.Setenv("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS", "legacy")
 	for _, test := range tests {
 		for _, profType := range test.Types {
 			// deltaProfiler returns an unstarted profiler that is fed prof1
@@ -171,6 +172,7 @@ main;bar 0 0 8 16
 }
 
 func TestRunProfile(t *testing.T) {
+	t.Setenv("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS", "legacy")
 	// TODO(felixge): These tests are directly calling the internal runProfile()
 	// function which is brittle. We should refactor them to use the public API.
 	t.Run("delta", func(t *testing.T) {

profiler/profiler_test.go

@@ -556,6 +556,7 @@ func TestExecutionTraceCPUProfileRate(t *testing.T) {
 	// fatal error: runtime: netpoll failed
 	cpuProfileRate := int(9999 + rand.Int63n(9999))
 
+	t.Setenv("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS", "legacy")
 	t.Setenv("DD_PROFILING_EXECUTION_TRACE_ENABLED", "true")
 	t.Setenv("DD_PROFILING_EXECUTION_TRACE_PERIOD", "10ms")
 	profile := <-startTestProfiler(t, 1,
@@ -912,6 +913,7 @@ func gzipDecompress(data []byte) ([]byte, error) {
 }
 
 func TestHeapProfileCompression(t *testing.T) {
+	t.Setenv("DD_PROFILING_DEBUG_COMPRESSION_SETTINGS", "legacy")
 	t.Run("delta", func(t *testing.T) { testHeapProfileCompression(t, true) })
 	t.Run("non-delta", func(t *testing.T) { testHeapProfileCompression(t, false) })
 }