bazel.go

Documentation: github.com/bazelbuild/rules_go/go/tools/gopackagesdriver

     1  // Copyright 2021 The Bazel Authors. All rights reserved.
     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 main
    16  
    17  import (
    18  	"bufio"
    19  	"bytes"
    20  	"context"
    21  	"encoding/json"
    22  	"errors"
    23  	"fmt"
    24  	"io/ioutil"
    25  	"net/url"
    26  	"os"
    27  	"os/exec"
    28  	"path/filepath"
    29  	"strings"
    30  )
    31  
    32  const (
    33  	toolTag = "gopackagesdriver"
    34  )
    35  
    36  type Bazel struct {
    37  	bazelBin          string
    38  	workspaceRoot     string
    39  	bazelStartupFlags []string
    40  	info              map[string]string
    41  	version           string
    42  }
    43  
    44  // Minimal BEP structs to access the build outputs
    45  type BEPNamedSet struct {
    46  	NamedSetOfFiles *struct {
    47  		Files []struct {
    48  			Name string `json:"name"`
    49  			URI  string `json:"uri"`
    50  		} `json:"files"`
    51  	} `json:"namedSetOfFiles"`
    52  }
    53  
    54  func NewBazel(ctx context.Context, bazelBin, workspaceRoot string, bazelStartupFlags []string) (*Bazel, error) {
    55  	b := &Bazel{
    56  		bazelBin:          bazelBin,
    57  		workspaceRoot:     workspaceRoot,
    58  		bazelStartupFlags: bazelStartupFlags,
    59  		version:           "6",
    60  	}
    61  	if err := b.fillInfo(ctx); err != nil {
    62  		return nil, fmt.Errorf("unable to query bazel info: %w", err)
    63  	}
    64  	return b, nil
    65  }
    66  
    67  func (b *Bazel) fillInfo(ctx context.Context) error {
    68  	b.info = map[string]string{}
    69  	output, err := b.run(ctx, "info")
    70  	if err != nil {
    71  		return err
    72  	}
    73  	scanner := bufio.NewScanner(bytes.NewBufferString(output))
    74  	for scanner.Scan() {
    75  		parts := strings.SplitN(strings.TrimSpace(scanner.Text()), ":", 2)
    76  		b.info[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
    77  	}
    78  	release := strings.Split(b.info["release"], " ")
    79  	if len(release) == 2 {
    80  		b.version = release[1]
    81  	}
    82  	return nil
    83  }
    84  
    85  func (b *Bazel) run(ctx context.Context, command string, args ...string) (string, error) {
    86  	defaultArgs := []string{
    87  		command,
    88  		"--tool_tag=" + toolTag,
    89  		"--ui_actions_shown=0",
    90  	}
    91  	cmd := exec.CommandContext(ctx, b.bazelBin, concatStringsArrays(b.bazelStartupFlags, defaultArgs, args)...)
    92  	fmt.Fprintln(os.Stderr, "Running:", cmd.Args)
    93  	cmd.Dir = b.WorkspaceRoot()
    94  	cmd.Stderr = os.Stderr
    95  	output, err := cmd.Output()
    96  	return string(output), err
    97  }
    98  
    99  func (b *Bazel) Build(ctx context.Context, args ...string) ([]string, error) {
   100  	jsonFile, err := ioutil.TempFile("", "gopackagesdriver_bep_")
   101  	if err != nil {
   102  		return nil, fmt.Errorf("unable to create BEP JSON file: %w", err)
   103  	}
   104  	defer func() {
   105  		jsonFile.Close()
   106  		os.Remove(jsonFile.Name())
   107  	}()
   108  
   109  	args = append([]string{
   110  		"--show_result=0",
   111  		"--build_event_json_file=" + jsonFile.Name(),
   112  		"--build_event_json_file_path_conversion=no",
   113  	}, args...)
   114  	if _, err := b.run(ctx, "build", args...); err != nil {
   115  		// Ignore a regular build failure to get partial data.
   116  		// See https://docs.bazel.build/versions/main/guide.html#what-exit-code-will-i-get on
   117  		// exit codes.
   118  		var exerr *exec.ExitError
   119  		if !errors.As(err, &exerr) || exerr.ExitCode() != 1 {
   120  			return nil, fmt.Errorf("bazel build failed: %w", err)
   121  		}
   122  	}
   123  
   124  	files := make([]string, 0)
   125  	decoder := json.NewDecoder(jsonFile)
   126  	for decoder.More() {
   127  		var namedSet BEPNamedSet
   128  		if err := decoder.Decode(&namedSet); err != nil {
   129  			return nil, fmt.Errorf("unable to decode %s: %w", jsonFile.Name(), err)
   130  		}
   131  
   132  		if namedSet.NamedSetOfFiles != nil {
   133  			for _, f := range namedSet.NamedSetOfFiles.Files {
   134  				fileUrl, err := url.Parse(f.URI)
   135  				if err != nil {
   136  					return nil, fmt.Errorf("unable to parse file URI: %w", err)
   137  				}
   138  				files = append(files, filepath.FromSlash(fileUrl.Path))
   139  			}
   140  		}
   141  	}
   142  
   143  	return files, nil
   144  }
   145  
   146  func (b *Bazel) Query(ctx context.Context, args ...string) ([]string, error) {
   147  	output, err := b.run(ctx, "query", args...)
   148  	if err != nil {
   149  		return nil, fmt.Errorf("bazel query failed: %w", err)
   150  	}
   151  
   152  	trimmedOutput := strings.TrimSpace(output)
   153  	if len(trimmedOutput) == 0 {
   154  		return nil, nil
   155  	}
   156  
   157  	return strings.Split(trimmedOutput, "\n"), nil
   158  }
   159  
   160  func (b *Bazel) WorkspaceRoot() string {
   161  	return b.workspaceRoot
   162  }
   163  
   164  func (b *Bazel) ExecutionRoot() string {
   165  	return b.info["execution_root"]
   166  }
   167  
   168  func (b *Bazel) OutputBase() string {
   169  	return b.info["output_base"]
   170  }
   171
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