github.com/distbuild/reclient@v0.0.0-20240401075343-3de72e395564/internal/pkg/downloadmismatch/diff.go (about)

     1  // Copyright 2023 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package downloadmismatch downloads compare build mismatch outputs.
    16  package downloadmismatch
    17  
    18  import (
    19  	"bytes"
    20  	"fmt"
    21  	"os"
    22  	"os/exec"
    23  	"path/filepath"
    24  )
    25  
    26  const (
    27  	stringsSuffix = ".strings"
    28  	diffFileName  = "compare_action.diff"
    29  )
    30  
    31  func runAndWriteOutput(outFp string, cmd *exec.Cmd) error {
    32  	cmd.Env = append(os.Environ())
    33  	var out bytes.Buffer
    34  	var stderr bytes.Buffer
    35  	cmd.Stderr = &stderr
    36  	cmd.Stdout = &out
    37  
    38  	// Ignore the command return code, non-zero code from e.g. diff is expected.
    39  	cmd.Run()
    40  
    41  	if stderr.Len() > 0 {
    42  		fmt.Printf("%v stderr: %q\n", cmd.String(), stderr.String())
    43  	}
    44  	return os.WriteFile(outFp, out.Bytes(), os.ModePerm)
    45  }
    46  
    47  func linuxStrings(fp string) (string, error) {
    48  	outFp := fp + stringsSuffix
    49  	return outFp, runAndWriteOutput(outFp, exec.Command("strings", fp))
    50  }
    51  
    52  // DiffReadableString diffs the strings outputs of the two inputs and store the diff outputs in outFp.
    53  func DiffReadableString(outFp, fp1, fp2 string) error {
    54  	fp1Strings, err1 := linuxStrings(fp1)
    55  	fp2Strings, err2 := linuxStrings(fp2)
    56  	if err1 != nil {
    57  		fmt.Printf("error reading %v: %v", fp1, err1)
    58  		return err1
    59  	}
    60  	if err2 != nil {
    61  		fmt.Printf("error reading %v: %v", fp1, err1)
    62  		return err2
    63  	}
    64  	return runAndWriteOutput(outFp, exec.Command("diff", fp1Strings, fp2Strings))
    65  }
    66  
    67  // Visit each action directory and diff remote vs local outputs. If one mismatch has multiple retries,
    68  // we only diff the first remote vs first local output.
    69  func visitAction(curPath string) error {
    70  	f, err := os.Open(curPath)
    71  	if err != nil {
    72  		return err
    73  	}
    74  	outputs, err := f.Readdir(0)
    75  	if err != nil {
    76  		return err
    77  	}
    78  	for _, output := range outputs {
    79  		// TODO: output can be directories if we modify
    80  		// download.go to download directories.
    81  		if err := visitOutput(filepath.Join(curPath, output.Name())); err != nil {
    82  			return err
    83  		}
    84  	}
    85  	return nil
    86  }
    87  
    88  func visitOutput(outputPath string) error {
    89  	localOutputs, err := os.ReadDir(filepath.Join(outputPath, LocalOutputDir))
    90  	if err != nil {
    91  		return err
    92  	}
    93  	remoteOutputs, err := os.ReadDir(filepath.Join(outputPath, RemoteOutputDir))
    94  	if err != nil {
    95  		return err
    96  	}
    97  	if len(localOutputs) != 1 || len(remoteOutputs) != 1 {
    98  		return fmt.Errorf("Missing or more than 1 local/remote output")
    99  	}
   100  
   101  	DiffReadableString(filepath.Join(outputPath, diffFileName), filepath.Join(outputPath, LocalOutputDir, localOutputs[0].Name()), filepath.Join(outputPath, RemoteOutputDir, remoteOutputs[0].Name()))
   102  	return nil
   103  }
   104  
   105  // DiffOutputDir visits the directory storing compare build outputs downloaded by this package.
   106  func DiffOutputDir(outputDir string) error {
   107  	dirs, err := os.ReadDir(outputDir)
   108  	if err != nil {
   109  		return err
   110  	}
   111  
   112  	for _, f := range dirs {
   113  		if f.IsDir() {
   114  			curPath := filepath.Join(outputDir, f.Name())
   115  			if err := visitAction(curPath); err != nil {
   116  				return err
   117  			}
   118  		} else {
   119  			return fmt.Errorf("Error iterating output Directory, %s is not directory", f.Name())
   120  		}
   121  	}
   122  	return nil
   123  }