container/env_test.go

package container // import "github.com/docker/docker/container"

import (
	"crypto/rand"
	"testing"

	"gotest.tools/v3/assert"
)

func TestReplaceAndAppendEnvVars(t *testing.T) {
	var (
		d = []string{"HOME=/", "FOO=foo_default"}
		// remove FOO from env
		// remove BAR from env (nop)
		o = []string{"HOME=/root", "TERM=xterm", "FOO", "BAR"}
	)

	env := ReplaceOrAppendEnvValues(d, o)
	t.Logf("default=%v, override=%v, result=%v", d, o, env)
	if len(env) != 2 {
		t.Fatalf("expected len of 2 got %d", len(env))
	}
	if env[0] != "HOME=/root" {
		t.Fatalf("expected HOME=/root got '%s'", env[0])
	}
	if env[1] != "TERM=xterm" {
		t.Fatalf("expected TERM=xterm got '%s'", env[1])
	}
}

func BenchmarkReplaceOrAppendEnvValues(b *testing.B) {
	b.Run("0", func(b *testing.B) {
		benchmarkReplaceOrAppendEnvValues(b, 0)
	})
	b.Run("100", func(b *testing.B) {
		benchmarkReplaceOrAppendEnvValues(b, 100)
	})
	b.Run("1000", func(b *testing.B) {
		benchmarkReplaceOrAppendEnvValues(b, 1000)
	})
	b.Run("10000", func(b *testing.B) {
		benchmarkReplaceOrAppendEnvValues(b, 10000)
	})
}

func benchmarkReplaceOrAppendEnvValues(b *testing.B, extraEnv int) {
	b.StopTimer()
	// remove FOO from env
	// remove BAR from env (nop)
	o := []string{"HOME=/root", "TERM=xterm", "FOO", "BAR"}

	if extraEnv > 0 {
		buf := make([]byte, 5)
		for i := 0; i < extraEnv; i++ {
			n, err := rand.Read(buf)
			assert.NilError(b, err)
			key := string(buf[:n])

			n, err = rand.Read(buf)
			assert.NilError(b, err)
			val := string(buf[:n])

			o = append(o, key+"="+val)
		}
	}
	d := make([]string, 0, len(o)+2)
	d = append(d, []string{"HOME=/", "FOO=foo_default"}...)

	b.StartTimer()
	for i := 0; i < b.N; i++ {
		_ = ReplaceOrAppendEnvValues(d, o)
	}
}