istio

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// Copyright Istio Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package dependencies
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import (
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	"bufio"
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	"fmt"
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	"io"
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	"os"
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	"strings"
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	"istio.io/istio/pkg/env"
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	"istio.io/istio/tools/istio-iptables/pkg/constants"
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)
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var DryRunFilePath = env.Register("DRY_RUN_FILE_PATH", "", "If provided, StdoutStubDependencies will write the input from stdin to the given file.")
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// TODO BML replace DIY mocks/state with something better
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type DependenciesStub struct {
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	ExecutedNormally []string
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	ExecutedQuietly  []string
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	ExecutedStdin    []string
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	ExecutedAll      []string
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}
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func (s *DependenciesStub) Run(cmd constants.IptablesCmd, iptVer *IptablesVersion, stdin io.ReadSeeker, args ...string) error {
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	s.execute(false /*quietly*/, cmd, iptVer, stdin, args...)
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	_ = s.writeAllToDryRunPath()
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	return nil
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}
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func (s *DependenciesStub) RunQuietlyAndIgnore(cmd constants.IptablesCmd, iptVer *IptablesVersion, stdin io.ReadSeeker, args ...string) {
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	s.execute(true /*quietly*/, cmd, iptVer, stdin, args...)
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	_ = s.writeAllToDryRunPath()
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}
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func (s *DependenciesStub) DetectIptablesVersion(ipV6 bool) (IptablesVersion, error) {
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	if ipV6 {
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		return IptablesVersion{
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			DetectedBinary:        "ip6tables",
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			DetectedSaveBinary:    "ip6tables-save",
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			DetectedRestoreBinary: "ip6tables-restore",
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		}, nil
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	}
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	return IptablesVersion{
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		DetectedBinary:        "iptables",
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		DetectedSaveBinary:    "iptables-save",
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		DetectedRestoreBinary: "iptables-restore",
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	}, nil
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}
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func (s *DependenciesStub) execute(quietly bool, cmd constants.IptablesCmd, iptVer *IptablesVersion, stdin io.ReadSeeker, args ...string) {
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	// We are either getting iptables rules as a `stdin` blob in `iptables-save` format (if this is a restore)
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	if stdin != nil {
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		buf := bufio.NewScanner(stdin)
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		for buf.Scan() {
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			stdincmd := buf.Text()
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			s.ExecutedAll = append(s.ExecutedAll, stdincmd)
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			s.ExecutedStdin = append(s.ExecutedStdin, stdincmd)
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		}
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	} else {
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		// ...or as discrete individual commands
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		cmdline := strings.Join(append([]string{iptVer.CmdToString(cmd)}, args...), " ")
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		s.ExecutedAll = append(s.ExecutedAll, cmdline)
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		if quietly {
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			s.ExecutedQuietly = append(s.ExecutedQuietly, cmdline)
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		} else {
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			s.ExecutedNormally = append(s.ExecutedNormally, cmdline)
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		}
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	}
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}
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// TODO BML this is more than a stub actually needs to do, we should be able to drop this testing hack
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// and skip writing to a file, but some tests are not *actually* doing unit testing and need this.
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func (s *DependenciesStub) writeAllToDryRunPath() error {
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	path := DryRunFilePath.Get()
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	if path != "" {
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		// Print the input into the given output file.
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		f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0o644)
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		if err != nil {
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			return fmt.Errorf("unable to open dry run output file %v: %v", path, err)
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		}
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		defer f.Close()
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		for _, line := range s.ExecutedAll {
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			_, err := f.WriteString(line + "\n")
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			if err != nil {
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				return fmt.Errorf("unable to write lines to dry run output file %v: %v", path, err)
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			}
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		}
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	}
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	return nil
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}
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