| 🛟 Updated. 28d5985 k33g 18h ago | 1 | package acp |
| 2 | |
| 3 | import ( |
| 4 | "bufio" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | "os" |
| 8 | "os/exec" |
| 9 | "path/filepath" |
| 10 | "sync" |
| 11 | ) |
| 12 | |
| 13 | // MaxLogLines is how much of an agent's standard error is kept for the status |
| 14 | // dialog. It is where a misconfigured model endpoint reports itself, and it is |
| 15 | // also where a chatty agent would otherwise grow without bound. |
| 16 | const MaxLogLines = 200 |
| 17 | |
| 18 | // process is a running agent: the child, its pipes as one stream, and whatever |
| 19 | // it has said on standard error. |
| 20 | type process struct { |
| 21 | command *exec.Cmd |
| 22 | stream io.ReadWriteCloser |
| 23 | |
| 24 | mu sync.Mutex |
| 25 | log []string |
| 26 | over int // lines dropped past the cap |
| 27 | } |
| 28 | |
| 29 | // pipes joins a child's stdin and stdout into the single stream jsonrpc wants. |
| 30 | // |
| 31 | // Closing it closes the input, which is how an agent is told to finish: every |
| 32 | // well-behaved one exits on end of input, so the process ends without a signal. |
| 33 | type pipes struct { |
| 34 | io.ReadCloser |
| 35 | io.WriteCloser |
| 36 | } |
| 37 | |
| 38 | // Close shuts both halves, reporting the first failure. |
| 39 | func (p pipes) Close() error { |
| 40 | writeErr := p.WriteCloser.Close() |
| 41 | readErr := p.ReadCloser.Close() |
| 42 | if writeErr != nil { |
| 43 | return writeErr |
| 44 | } |
| 45 | return readErr |
| 46 | } |
| 47 | |
| 48 | // startProcess runs an agent and returns it, with its pipes joined into one |
| 49 | // stream and its standard error being drained. |
| 50 | // |
| 51 | // The child's environment is the editor's with the agent's own added on top, so |
| 52 | // a credential already in the environment reaches the agent without being |
| 53 | // written into a file. |
| 54 | func startProcess(agent Agent, projectDir string, onLog func(string)) (*process, error) { |
| 55 | command := exec.Command(agent.Command, agent.Args...) |
| 56 | command.Dir = workingDirectory(agent, projectDir) |
| 57 | command.Env = environment(agent) |
| 58 | |
| 59 | stdin, err := command.StdinPipe() |
| 60 | if err != nil { |
| 61 | return nil, fmt.Errorf("acp: connecting to %s: %w", agent.Command, err) |
| 62 | } |
| 63 | stdout, err := command.StdoutPipe() |
| 64 | if err != nil { |
| 65 | return nil, fmt.Errorf("acp: connecting to %s: %w", agent.Command, err) |
| 66 | } |
| 67 | stderr, err := command.StderrPipe() |
| 68 | if err != nil { |
| 69 | return nil, fmt.Errorf("acp: connecting to %s: %w", agent.Command, err) |
| 70 | } |
| 71 | |
| 72 | if err := command.Start(); err != nil { |
| 73 | return nil, fmt.Errorf("acp: starting %s: %w", agent.CommandLine(), err) |
| 74 | } |
| 75 | |
| 76 | p := &process{command: command, stream: pipes{ReadCloser: stdout, WriteCloser: stdin}} |
| 77 | go p.drain(stderr, onLog) |
| 78 | return p, nil |
| 79 | } |
| 80 | |
| 81 | // workingDirectory returns where the agent should run: its own cwd if it named |
| 82 | // one, and the project otherwise. |
| 83 | func workingDirectory(agent Agent, projectDir string) string { |
| 84 | if agent.Cwd == "" { |
| 85 | return projectDir |
| 86 | } |
| 87 | if filepath.IsAbs(agent.Cwd) { |
| 88 | return agent.Cwd |
| 89 | } |
| 90 | return filepath.Join(projectDir, agent.Cwd) |
| 91 | } |
| 92 | |
| 93 | // environment returns the child's environment: the editor's, plus the agent's. |
| 94 | func environment(agent Agent) []string { |
| 95 | if len(agent.Env) == 0 { |
| 96 | return nil // nil means "inherit", which is what os/exec does with it |
| 97 | } |
| 98 | |
| 99 | env := os.Environ() |
| 100 | for name, value := range agent.Env { |
| 101 | env = append(env, name+"="+value) |
| 102 | } |
| 103 | return env |
| 104 | } |
| 105 | |
| 106 | // drain reads the agent's standard error, keeping the last lines of it. |
| 107 | // |
| 108 | // It must be read rather than ignored: a full pipe blocks the child, and an |
| 109 | // agent that logs enough would stop answering with no error anywhere. It is |
| 110 | // also not protocol — `docker agent` prints a welcome banner here — so nothing |
| 111 | // read from it ever reaches the JSON-RPC layer. |
| 112 | func (p *process) drain(stderr io.Reader, onLog func(string)) { |
| 113 | scanner := bufio.NewScanner(stderr) |
| 114 | scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024) |
| 115 | |
| 116 | for scanner.Scan() { |
| 117 | line := scanner.Text() |
| 118 | p.record(line) |
| 119 | if onLog != nil { |
| 120 | onLog(line) |
| 121 | } |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | // record keeps one line of the log, dropping the oldest past the cap. |
| 126 | func (p *process) record(line string) { |
| 127 | p.mu.Lock() |
| 128 | defer p.mu.Unlock() |
| 129 | |
| 130 | p.log = append(p.log, line) |
| 131 | if len(p.log) > MaxLogLines { |
| 132 | p.log = p.log[len(p.log)-MaxLogLines:] |
| 133 | p.over++ |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | // Log returns what the agent has said on standard error, most recent last. |
| 138 | func (p *process) Log() []string { |
| 139 | p.mu.Lock() |
| 140 | defer p.mu.Unlock() |
| 141 | |
| 142 | out := make([]string, len(p.log)) |
| 143 | copy(out, p.log) |
| 144 | return out |
| 145 | } |
| 146 | |
| 147 | // Dropped returns how many log lines were lost to the cap. |
| 148 | func (p *process) Dropped() int { |
| 149 | p.mu.Lock() |
| 150 | defer p.mu.Unlock() |
| 151 | return p.over |
| 152 | } |
| 153 | |
| 154 | // Stop ends the agent. |
| 155 | // |
| 156 | // Closing the stream closes its standard input, which is how the protocol says |
| 157 | // to finish: an agent reading end of input exits. The process is then killed |
| 158 | // anyway, because an agent that ignores it must not outlive the window — and |
| 159 | // Wait is what stops it becoming a zombie. |
| 160 | func (p *process) Stop() error { |
| 161 | err := p.stream.Close() |
| 162 | if p.command.Process != nil { |
| 163 | _ = p.command.Process.Kill() |
| 164 | } |
| 165 | _ = p.command.Wait() |
| 166 | return err |
| 167 | } |