tools/gn/function_exec_script.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/command_line.h"
   6 #include "base/files/file_util.h"
   7 #include "base/logging.h"
   8 #include "base/strings/string_number_conversions.h"
   9 #include "base/strings/utf_string_conversions.h"
  10 #include "base/time/time.h"
  11 #include "build/build_config.h"
  12 #include "tools/gn/err.h"
  13 #include "tools/gn/exec_process.h"
  14 #include "tools/gn/filesystem_utils.h"
  15 #include "tools/gn/functions.h"
  16 #include "tools/gn/input_conversion.h"
  17 #include "tools/gn/input_file.h"
  18 #include "tools/gn/parse_tree.h"
  19 #include "tools/gn/scheduler.h"
  20 #include "tools/gn/trace.h"
  21 #include "tools/gn/value.h"
  22
  23 namespace functions {
  24
  25 const char kExecScript[] = "exec_script";
  26 const char kExecScript_HelpShort[] =
  27     "exec_script: Synchronously run a script and return the output.";
  28 const char kExecScript_Help[] =
  29     "exec_script: Synchronously run a script and return the output.\n"
  30     "\n"
  31     "  exec_script(filename,\n"
  32     "              arguments = [],\n"
  33     "              input_conversion = \"\",\n"
  34     "              file_dependencies = [])\n"
  35     "\n"
  36     "  Runs the given script, returning the stdout of the script. The build\n"
  37     "  generation will fail if the script does not exist or returns a nonzero\n"
  38     "  exit code.\n"
  39     "\n"
  40     "  The current directory when executing the script will be the root\n"
  41     "  build directory. If you are passing file names, you will want to use\n"
  42     "  the rebase_path() function to make file names relative to this\n"
  43     "  path (see \"gn help rebase_path\").\n"
  44     "\n"
  45     "Arguments:\n"
  46     "\n"
  47     "  filename:\n"
  48     "      File name of python script to execute. Non-absolute names will\n"
  49     "      be treated as relative to the current build file.\n"
  50     "\n"
  51     "  arguments:\n"
  52     "      A list of strings to be passed to the script as arguments.\n"
  53     "      May be unspecified or the empty list which means no arguments.\n"
  54     "\n"
  55     "  input_conversion:\n"
  56     "      Controls how the file is read and parsed.\n"
  57     "      See \"gn help input_conversion\".\n"
  58     "\n"
  59     "      If unspecified, defaults to the empty string which causes the\n"
  60     "      script result to be discarded. exec script will return None.\n"
  61     "\n"
  62     "  dependencies:\n"
  63     "      (Optional) A list of files that this script reads or otherwise\n"
  64     "      depends on. These dependencies will be added to the build result\n"
  65     "      such that if any of them change, the build will be regenerated and\n"
  66     "      the script will be re-run.\n"
  67     "\n"
  68     "      The script itself will be an implicit dependency so you do not\n"
  69     "      need to list it.\n"
  70     "\n"
  71     "Example:\n"
  72     "\n"
  73     "  all_lines = exec_script(\n"
  74     "      \"myscript.py\", [some_input], \"list lines\",\n"
  75     "      [ rebase_path(\"data_file.txt\", root_build_dir) ])\n"
  76     "\n"
  77     "  # This example just calls the script with no arguments and discards\n"
  78     "  # the result.\n"
  79     "  exec_script(\"//foo/bar/myscript.py\")\n";
  80
  81 Value RunExecScript(Scope* scope,
  82                     const FunctionCallNode* function,
  83                     const std::vector<Value>& args,
  84                     Err* err) {
  85   if (args.size() < 1 || args.size() > 4) {
  86     *err = Err(function->function(), "Wrong number of arguments to exec_script",
  87                "I expected between one and four arguments.");
  88     return Value();
  89   }
  90
  91   const Settings* settings = scope->settings();
  92   const BuildSettings* build_settings = settings->build_settings();
  93   const SourceDir& cur_dir = scope->GetSourceDir();
  94
  95   // Find the python script to run.
  96   if (!args[0].VerifyTypeIs(Value::STRING, err))
  97     return Value();
  98   SourceFile script_source =
  99       cur_dir.ResolveRelativeFile(args[0].string_value(),
 100           scope->settings()->build_settings()->root_path_utf8());
 101   base::FilePath script_path = build_settings->GetFullPath(script_source);
 102   if (!build_settings->secondary_source_path().empty() &&
 103       !base::PathExists(script_path)) {
 104     // Fall back to secondary source root when the file doesn't exist.
 105     script_path = build_settings->GetFullPathSecondary(script_source);
 106   }
 107
 108   ScopedTrace trace(TraceItem::TRACE_SCRIPT_EXECUTE, script_source.value());
 109   trace.SetToolchain(settings->toolchain_label());
 110
 111   // Add all dependencies of this script, including the script itself, to the
 112   // build deps.
 113   g_scheduler->AddGenDependency(script_path);
 114   if (args.size() == 4) {
 115     const Value& deps_value = args[3];
 116     if (!deps_value.VerifyTypeIs(Value::LIST, err))
 117       return Value();
 118
 119     for (const auto& dep : deps_value.list_value()) {
 120       if (!dep.VerifyTypeIs(Value::STRING, err))
 121         return Value();
 122       g_scheduler->AddGenDependency(
 123           build_settings->GetFullPath(cur_dir.ResolveRelativeFile(
 124               dep.string_value(),
 125               scope->settings()->build_settings()->root_path_utf8())));
 126     }
 127   }
 128
 129   // Make the command line.
 130   const base::FilePath& python_path = build_settings->python_path();
 131   CommandLine cmdline(python_path);
 132   cmdline.AppendArgPath(script_path);
 133
 134   if (args.size() >= 2) {
 135     // Optional command-line arguments to the script.
 136     const Value& script_args = args[1];
 137     if (!script_args.VerifyTypeIs(Value::LIST, err))
 138       return Value();
 139     for (const auto& arg : script_args.list_value()) {
 140       if (!arg.VerifyTypeIs(Value::STRING, err))
 141         return Value();
 142       cmdline.AppendArg(arg.string_value());
 143     }
 144   }
 145
 146   // Log command line for debugging help.
 147   trace.SetCommandLine(cmdline);
 148   base::TimeTicks begin_exec;
 149   if (g_scheduler->verbose_logging()) {
 150 #if defined(OS_WIN)
 151     g_scheduler->Log("Pythoning",
 152                      base::UTF16ToUTF8(cmdline.GetCommandLineString()));
 153 #else
 154     g_scheduler->Log("Pythoning", cmdline.GetCommandLineString());
 155 #endif
 156     begin_exec = base::TimeTicks::Now();
 157   }
 158
 159   base::FilePath startup_dir =
 160       build_settings->GetFullPath(build_settings->build_dir());
 161   // The first time a build is run, no targets will have been written so the
 162   // build output directory won't exist. We need to make sure it does before
 163   // running any scripts with this as its startup directory, although it will
 164   // be relatively rare that the directory won't exist by the time we get here.
 165   //
 166   // If this shows up on benchmarks, we can cache whether we've done this
 167   // or not and skip creating the directory.
 168   base::CreateDirectory(startup_dir);
 169
 170   // Execute the process.
 171   // TODO(brettw) set the environment block.
 172   std::string output;
 173   std::string stderr_output;
 174   int exit_code = 0;
 175   if (!internal::ExecProcess(
 176           cmdline, startup_dir, &output, &stderr_output, &exit_code)) {
 177     *err = Err(function->function(), "Could not execute python.",
 178         "I was trying to execute \"" + FilePathToUTF8(python_path) + "\".");
 179     return Value();
 180   }
 181   if (g_scheduler->verbose_logging()) {
 182     g_scheduler->Log("Pythoning", script_source.value() + " took " +
 183         base::Int64ToString(
 184             (base::TimeTicks::Now() - begin_exec).InMilliseconds()) +
 185         "ms");
 186   }
 187
 188   if (exit_code != 0) {
 189     std::string msg = "Current dir: " + FilePathToUTF8(startup_dir) +
 190         "\nCommand: " + FilePathToUTF8(cmdline.GetCommandLineString()) +
 191         "\nReturned " + base::IntToString(exit_code);
 192     if (!output.empty())
 193       msg += " and printed out:\n\n" + output;
 194     else
 195       msg += ".";
 196     if (!stderr_output.empty())
 197       msg += "\nstderr:\n\n" + stderr_output;
 198
 199     *err = Err(function->function(), "Script returned non-zero exit code.",
 200                msg);
 201     return Value();
 202   }
 203
 204   // Default to None value for the input conversion if unspecified.
 205   return ConvertInputToValue(scope->settings(), output, function,
 206                              args.size() >= 3 ? args[2] : Value(), err);
 207 }
 208
 209 }  // namespace functions