Add an aos_send

It's basically the opposite of aos_dump.

Change-Id: I12fc53f8afbc3eef3ad4293d37b1a575e7a8d596
diff --git a/aos/BUILD b/aos/BUILD
index 7c976b1..8e2d8ac 100644
--- a/aos/BUILD
+++ b/aos/BUILD
@@ -7,6 +7,7 @@
     srcs = [
         "//aos:aos_dump",
         "//aos:aos_dump_autocomplete.sh",
+        "//aos:aos_send",
         "//aos/starter",
     ],
     visibility = ["//visibility:public"],
@@ -23,10 +24,10 @@
 filegroup(
     name = "prime_binaries_stripped",
     srcs = [
-        # starter is hard coded to look for a non-stripped core...
         "//aos:aos_dump.stripped",
-        "//aos/starter",
         "//aos:aos_dump_autocomplete.sh",
+        "//aos:aos_send.stripped",
+        "//aos/starter",
     ],
     visibility = ["//visibility:public"],
 )
@@ -488,6 +489,24 @@
     ],
 )
 
+cc_library(
+    name = "aos_cli_utils",
+    srcs = [
+        "aos_cli_utils.cc",
+    ],
+    hdrs = [
+        "aos_cli_utils.h",
+    ],
+    target_compatible_with = ["@platforms//os:linux"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":configuration",
+        "//aos:init",
+        "//aos/events:shm_event_loop",
+        "@com_github_google_glog//:glog",
+    ],
+)
+
 cc_binary(
     name = "aos_dump",
     srcs = [
@@ -496,10 +515,27 @@
     target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
+        ":aos_cli_utils",
         ":configuration",
         ":json_to_flatbuffer",
         "//aos:init",
-        "//aos/events:shm_event_loop",
+        "@com_github_google_glog//:glog",
+    ],
+)
+
+cc_binary(
+    name = "aos_send",
+    srcs = [
+        "aos_send.cc",
+    ],
+    target_compatible_with = ["@platforms//os:linux"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":aos_cli_utils",
+        ":configuration",
+        ":init",
+        ":json_to_flatbuffer",
+        "@com_github_gflags_gflags//:gflags",
         "@com_github_google_glog//:glog",
     ],
 )
diff --git a/aos/aos_cli_utils.cc b/aos/aos_cli_utils.cc
new file mode 100644
index 0000000..e36c3d2
--- /dev/null
+++ b/aos/aos_cli_utils.cc
@@ -0,0 +1,162 @@
+#include "aos/aos_cli_utils.h"
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <iostream>
+
+DEFINE_string(config, "./config.json", "File path of aos configuration");
+
+DEFINE_bool(
+    _bash_autocomplete, false,
+    "Internal use: Outputs channel list for use with autocomplete script.");
+DEFINE_string(_bash_autocomplete_word, "",
+              "Internal use: Current word being autocompleted");
+
+DEFINE_bool(all, false,
+            "If true, print out the channels for all nodes, not just the "
+            "channels which are visible on this node.");
+
+namespace aos {
+namespace {
+
+bool EndsWith(std::string_view str, std::string_view ending) {
+  const std::size_t offset = str.size() - ending.size();
+  return str.size() >= ending.size() &&
+         std::equal(str.begin() + offset, str.end(), ending.begin(),
+                    ending.end());
+}
+
+}  // namespace
+
+bool CliUtilInfo::Initialize(
+    int *argc, char ***argv,
+    std::function<bool(const aos::Channel *)> channel_filter) {
+  // Don't generate failure output if the config doesn't exist while attempting
+  // to autocomplete.
+  if (struct stat file_stat;
+      FLAGS__bash_autocomplete &&
+      (!(EndsWith(FLAGS_config, ".json") || EndsWith(FLAGS_config, ".bfbs")) ||
+       stat(FLAGS_config.c_str(), &file_stat) != 0 ||
+       (file_stat.st_mode & S_IFMT) != S_IFREG)) {
+    std::cout << "COMPREPLY=()";
+    return true;
+  }
+
+  std::string channel_name;
+  std::string message_type;
+  if (*argc > 1) {
+    channel_name = (*argv)[1];
+    ShiftArgs(argc, argv);
+  }
+  if (*argc > 1) {
+    message_type = (*argv)[1];
+    ShiftArgs(argc, argv);
+  }
+
+  config.emplace(aos::configuration::ReadConfig(FLAGS_config));
+  event_loop.emplace(&config->message());
+  event_loop->SkipTimingReport();
+  event_loop->SkipAosLog();
+
+  if (FLAGS__bash_autocomplete) {
+    Autocomplete(channel_name, message_type, channel_filter);
+    return true;
+  }
+
+  const flatbuffers::Vector<flatbuffers::Offset<aos::Channel>> *const channels =
+      event_loop->configuration()->channels();
+  if (channel_name.empty() && message_type.empty()) {
+    std::cout << "Channels:\n";
+    for (const aos::Channel *channel : *channels) {
+      if (FLAGS_all || channel_filter(channel)) {
+        std::cout << channel->name()->c_str() << ' ' << channel->type()->c_str()
+                  << '\n';
+      }
+    }
+    return true;
+  }
+
+  bool found_exact = false;
+  for (const aos::Channel *channel : *channels) {
+    if (!FLAGS_all && !channel_filter(channel)) {
+      continue;
+    }
+    if (channel->name()->c_str() != channel_name) {
+      continue;
+    }
+    if (channel->type()->string_view() == message_type) {
+      if (!found_exact) {
+        found_channels.clear();
+        found_exact = true;
+      }
+    } else if (!found_exact && channel->type()->string_view().find(
+                                   message_type) != std::string_view::npos) {
+    } else {
+      continue;
+    }
+    found_channels.push_back(channel);
+  }
+
+  if (found_channels.empty()) {
+    LOG(FATAL) << "Could not find any channels with the given name and type.";
+  } else if (found_channels.size() > 1 && !message_type.empty()) {
+    LOG(FATAL) << "Multiple channels found with same type";
+  }
+
+  return false;
+}
+
+void CliUtilInfo::Autocomplete(
+    std::string_view channel_name, std::string_view message_type,
+    std::function<bool(const aos::Channel *)> channel_filter) {
+  const aos::Configuration *const config_msg = event_loop->configuration();
+  const bool unique_match =
+      std::count_if(config_msg->channels()->begin(),
+                    config_msg->channels()->end(),
+                    [channel_name, message_type](const aos::Channel *channel) {
+                      return channel->name()->string_view() == channel_name &&
+                             channel->type()->string_view() == message_type;
+                    }) == 1;
+
+  const bool editing_message =
+      !channel_name.empty() && FLAGS__bash_autocomplete_word == message_type;
+  const bool editing_channel =
+      !editing_message && FLAGS__bash_autocomplete_word == channel_name;
+
+  std::cout << "COMPREPLY=(";
+
+  // If we have a unique match, don't provide any suggestions. Otherwise, check
+  // that were're editing one of the two positional arguments.
+  if (!unique_match && (editing_message || editing_channel)) {
+    for (const aos::Channel *channel : *config_msg->channels()) {
+      if (FLAGS_all || channel_filter(channel)) {
+        // Suggest only message types if the message type argument is being
+        // entered.
+        if (editing_message) {
+          // Then, filter for only channel names that match exactly and types
+          // that begin with message_type.
+          if (channel->name()->string_view() == channel_name &&
+              channel->type()->string_view().find(message_type) == 0) {
+            std::cout << '\'' << channel->type()->c_str() << "' ";
+          }
+        } else if (channel->name()->string_view().find(channel_name) == 0) {
+          // If the message type empty, then return full autocomplete.
+          // Otherwise, since the message type is poulated yet not being edited,
+          // the user must be editing the channel name alone, in which case only
+          // suggest channel names, not pairs.
+          if (message_type.empty()) {
+            std::cout << '\'' << channel->name()->c_str() << ' '
+                      << channel->type()->c_str() << "' ";
+          } else {
+            std::cout << '\'' << channel->name()->c_str() << "' ";
+          }
+        }
+      }
+    }
+  }
+  std::cout << ')';
+}
+
+}  // namespace aos
diff --git a/aos/aos_cli_utils.h b/aos/aos_cli_utils.h
new file mode 100644
index 0000000..e158737
--- /dev/null
+++ b/aos/aos_cli_utils.h
@@ -0,0 +1,42 @@
+#ifndef AOS_AOS_CLI_UTILS_H_
+#define AOS_AOS_CLI_UTILS_H_
+
+#include "aos/configuration.h"
+#include "aos/events/shm_event_loop.h"
+#include "gflags/gflags.h"
+
+namespace aos {
+
+// The information needed by the main function of a CLI tool.
+struct CliUtilInfo {
+  // If this returns true, main should return immediately with 0.
+  // If this returns false, the other fields will be filled out appropriately.
+  // event_loop will be filled out before channel_filter is called.
+  bool Initialize(int *argc, char ***argv,
+                  std::function<bool(const aos::Channel *)> channel_filter);
+
+  std::optional<aos::FlatbufferDetachedBuffer<aos::Configuration>> config;
+  std::optional<aos::ShmEventLoop> event_loop;
+  std::vector<const aos::Channel *> found_channels;
+
+ private:
+  // Generate eval command to populate autocomplete responses. Eval escapes
+  // spaces so channels are paired with their types. If a complete channel name
+  // is found, only autocompletes the type to avoid repeating arguments. Returns
+  // no autocomplete suggestions if a channel and type is found with the current
+  // arguments.
+  void Autocomplete(std::string_view channel_name,
+                    std::string_view message_type,
+                    std::function<bool(const aos::Channel *)> channel_filter);
+
+  void ShiftArgs(int *argc, char ***argv) {
+    for (int i = 1; i + 1 < *argc; ++i) {
+      (*argv)[i] = (*argv)[i + 1];
+    }
+    --*argc;
+  }
+};
+
+}  // namespace aos
+
+#endif  // AOS_AOS_CLI_UTILS_H_
diff --git a/aos/aos_dump.cc b/aos/aos_dump.cc
index 3484b73..78df645 100644
--- a/aos/aos_dump.cc
+++ b/aos/aos_dump.cc
@@ -1,35 +1,25 @@
 #include <unistd.h>
 
 #include <iostream>
-#include <map>
 
+#include "aos/aos_cli_utils.h"
 #include "aos/configuration.h"
-#include "aos/events/shm_event_loop.h"
 #include "aos/init.h"
 #include "aos/json_to_flatbuffer.h"
 #include "gflags/gflags.h"
 
-DEFINE_string(config, "./config.json", "File path of aos configuration");
 DEFINE_int32(max_vector_size, 100,
              "If positive, vectors longer than this will not be printed");
 DEFINE_bool(fetch, false,
             "If true, fetch the current message on the channel first");
 DEFINE_bool(pretty, false,
             "If true, pretty print the messages on multiple lines");
-DEFINE_bool(all, false,
-            "If true, print out the channels for all nodes, not just the "
-            "channels which are visible on this node.");
 DEFINE_bool(print_timestamps, true, "If true, timestamps are printed.");
 DEFINE_uint64(count, 0,
               "If >0, aos_dump will exit after printing this many messages.");
 DEFINE_int32(rate_limit, 0,
              "The minimum amount of time to wait in milliseconds before "
              "sending another message");
-DEFINE_bool(
-    _bash_autocomplete, false,
-    "Internal use: Outputs channel list for use with autocomplete script.");
-DEFINE_string(_bash_autocomplete_word, "",
-              "Intenal use: Current word being autocompleted");
 
 namespace {
 
@@ -60,70 +50,6 @@
   }
 }
 
-// Generate eval command to populate autocomplete responses. Eval escapes spaces
-// so channels are paired with their types. If a complete channel name is found,
-// only autocompletes the type to avoid repeating arguments. Returns no
-// autocomplete suggestions if a channel and type is found with the current
-// arguments.
-void Autocomplete(const aos::Configuration *config_msg,
-                  const aos::ShmEventLoop &event_loop,
-                  std::string_view channel_name,
-                  std::string_view message_type) {
-  const bool unique_match =
-      std::count_if(config_msg->channels()->begin(),
-                    config_msg->channels()->end(),
-                    [channel_name, message_type](const aos::Channel *channel) {
-                      return channel->name()->string_view() == channel_name &&
-                             channel->type()->string_view() == message_type;
-                    }) == 1;
-
-  const bool editing_message =
-      !channel_name.empty() && FLAGS__bash_autocomplete_word == message_type;
-  const bool editing_channel =
-      !editing_message && FLAGS__bash_autocomplete_word == channel_name;
-
-  std::cout << "COMPREPLY=(";
-
-  // If we have a unique match, don't provide any suggestions. Otherwise, check
-  // that were're editing one of the two positional arguments.
-  if (!unique_match && (editing_message || editing_channel)) {
-    for (const aos::Channel *channel : *config_msg->channels()) {
-      if (FLAGS_all || aos::configuration::ChannelIsReadableOnNode(
-                           channel, event_loop.node())) {
-        // Suggest only message types if the message type argument is being
-        // entered.
-        if (editing_message) {
-          // Then, filter for only channel names that match exactly and types
-          // that begin with message_type.
-          if (channel->name()->string_view() == channel_name &&
-              channel->type()->string_view().find(message_type) == 0) {
-            std::cout << '\'' << channel->type()->c_str() << "' ";
-          }
-        } else if (channel->name()->string_view().find(channel_name) == 0) {
-          // If the message type empty, then return full autocomplete.
-          // Otherwise, since the message type is poulated yet not being edited,
-          // the user must be editing the channel name alone, in which case only
-          // suggest channel names, not pairs.
-          if (message_type.empty()) {
-            std::cout << '\'' << channel->name()->c_str() << ' '
-                      << channel->type()->c_str() << "' ";
-          } else {
-            std::cout << '\'' << channel->name()->c_str() << "' ";
-          }
-        }
-      }
-    }
-  }
-  std::cout << ')';
-}
-
-bool EndsWith(std::string_view str, std::string_view ending) {
-  const std::size_t offset = str.size() - ending.size();
-  return str.size() >= ending.size() &&
-         std::equal(str.begin() + offset, str.end(), ending.begin(),
-                    ending.end());
-}
-
 }  // namespace
 
 int main(int argc, char **argv) {
@@ -135,92 +61,25 @@
       "/test aos.examples.Ping");
   aos::InitGoogle(&argc, &argv);
 
-  // Don't generate failure output if the config doesn't exist while attempting
-  // to autocomplete.
-  if (struct stat file_stat;
-      FLAGS__bash_autocomplete &&
-      (!(EndsWith(FLAGS_config, ".json") || EndsWith(FLAGS_config, ".bfbs")) ||
-       stat(FLAGS_config.c_str(), &file_stat) != 0 ||
-       (file_stat.st_mode & S_IFMT) != S_IFREG)) {
-    std::cout << "COMPREPLY=()";
+  aos::CliUtilInfo cli_info;
+  if (cli_info.Initialize(&argc, &argv,
+                          [&cli_info](const aos::Channel *channel) {
+                            return aos::configuration::ChannelIsReadableOnNode(
+                                channel, cli_info.event_loop->node());
+                          })) {
     return 0;
   }
 
-  std::string channel_name;
-  std::string message_type;
-  if (argc > 1) {
-    channel_name = argv[1];
-  }
-  if (argc > 2) {
-    message_type = argv[2];
-  }
-
-  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
-      aos::configuration::ReadConfig(FLAGS_config);
-
-  const aos::Configuration *config_msg = &config.message();
-  aos::ShmEventLoop event_loop(config_msg);
-  event_loop.SkipTimingReport();
-  event_loop.SkipAosLog();
-
-  if (FLAGS__bash_autocomplete) {
-    Autocomplete(config_msg, event_loop, channel_name, message_type);
-    return 0;
-  }
-
-  if (argc == 1) {
-    std::cout << "Channels:\n";
-    for (const aos::Channel *channel : *config_msg->channels()) {
-      if (FLAGS_all || aos::configuration::ChannelIsReadableOnNode(
-                           channel, event_loop.node())) {
-        std::cout << channel->name()->c_str() << ' ' << channel->type()->c_str()
-                  << '\n';
-      }
-    }
-    return 0;
-  }
-
-  std::vector<const aos::Channel *> found_channels;
-  const flatbuffers::Vector<flatbuffers::Offset<aos::Channel>> *channels =
-      config_msg->channels();
-  bool found_exact = false;
-  for (const aos::Channel *channel : *channels) {
-    if (!FLAGS_all && !aos::configuration::ChannelIsReadableOnNode(
-                          channel, event_loop.node())) {
-      continue;
-    }
-    if (channel->name()->c_str() != channel_name) {
-      continue;
-    }
-    if (channel->type()->string_view() == message_type) {
-      if (!found_exact) {
-        found_channels.clear();
-        found_exact = true;
-      }
-    } else if (!found_exact && channel->type()->string_view().find(
-                                   message_type) != std::string_view::npos) {
-    } else {
-      continue;
-    }
-    found_channels.push_back(channel);
-  }
-
-  if (found_channels.empty()) {
-    LOG(FATAL) << "Could not find any channels with the given name and type.";
-  } else if (found_channels.size() > 1 && !message_type.empty()) {
-    LOG(FATAL) << "Multiple channels found with same type";
-  }
-
   uint64_t message_count = 0;
 
   aos::FastStringBuilder str_builder;
 
   aos::monotonic_clock::time_point next_send_time =
       aos::monotonic_clock::min_time;
-  for (const aos::Channel *channel : found_channels) {
+  for (const aos::Channel *channel : cli_info.found_channels) {
     if (FLAGS_fetch) {
       const std::unique_ptr<aos::RawFetcher> fetcher =
-          event_loop.MakeRawFetcher(channel);
+          cli_info.event_loop->MakeRawFetcher(channel);
       if (fetcher->Fetch()) {
         PrintMessage(channel, fetcher->context(), &str_builder);
         ++message_count;
@@ -231,9 +90,9 @@
       return 0;
     }
 
-    event_loop.MakeRawWatcher(
+    cli_info.event_loop->MakeRawWatcher(
         channel,
-        [channel, &str_builder, &event_loop, &message_count, &next_send_time](
+        [channel, &str_builder, &cli_info, &message_count, &next_send_time](
             const aos::Context &context, const void * /*message*/) {
           if (context.monotonic_event_time > next_send_time) {
             PrintMessage(channel, context, &str_builder);
@@ -241,13 +100,13 @@
             next_send_time = context.monotonic_event_time +
                              std::chrono::milliseconds(FLAGS_rate_limit);
             if (FLAGS_count > 0 && message_count >= FLAGS_count) {
-              event_loop.Exit();
+              cli_info.event_loop->Exit();
             }
           }
         });
   }
 
-  event_loop.Run();
+  cli_info.event_loop->Run();
 
   return 0;
 }
diff --git a/aos/aos_dump_autocomplete.sh b/aos/aos_dump_autocomplete.sh
index a49c540..c62af99 100644
--- a/aos/aos_dump_autocomplete.sh
+++ b/aos/aos_dump_autocomplete.sh
@@ -5,3 +5,5 @@
 
 complete -F _aosdump_completions -o default aos_dump
 complete -F _aosdump_completions -o default aos_dump.stripped
+complete -F _aosdump_completions -o default aos_send
+complete -F _aosdump_completions -o default aos_send.stripped
diff --git a/aos/aos_send.cc b/aos/aos_send.cc
new file mode 100644
index 0000000..d0dea01
--- /dev/null
+++ b/aos/aos_send.cc
@@ -0,0 +1,47 @@
+#include <unistd.h>
+
+#include <iostream>
+
+#include "aos/aos_cli_utils.h"
+#include "aos/configuration.h"
+#include "aos/init.h"
+#include "aos/json_to_flatbuffer.h"
+#include "gflags/gflags.h"
+#include "glog/logging.h"
+
+int main(int argc, char **argv) {
+  gflags::SetUsageMessage(
+      "Sends messages on arbitrary channels.\n"
+      "Typical Usage: aos_send [--config path_to_config.json]"
+      " channel_name message_type '{\"foo\": \"bar\"}'\n"
+      "Example usage: aos_send /test aos.examples.Ping "
+      "'{\"value\": 1}'");
+  aos::InitGoogle(&argc, &argv);
+
+  aos::CliUtilInfo cli_info;
+  if (cli_info.Initialize(&argc, &argv,
+                          [&cli_info](const aos::Channel *channel) {
+                            return aos::configuration::ChannelIsSendableOnNode(
+                                channel, cli_info.event_loop->node());
+                          })) {
+    return 0;
+  }
+  if (cli_info.found_channels.size() > 1) {
+    LOG(FATAL) << "Matched multiple channels, but may only send on 1";
+  }
+
+  if (argc == 1) {
+    LOG(FATAL) << "Must specify a message to send";
+  }
+
+  const aos::Channel *const channel = cli_info.found_channels[0];
+  const std::unique_ptr<aos::RawSender> sender =
+      cli_info.event_loop->MakeRawSender(channel);
+  flatbuffers::FlatBufferBuilder fbb(sender->fbb_allocator()->size(),
+                                     sender->fbb_allocator());
+  fbb.Finish(aos::JsonToFlatbuffer(std::string_view(argv[1]), channel->schema(),
+                                   &fbb));
+  sender->Send(fbb.GetSize());
+
+  return 0;
+}