Enable passing cloud-init config via stdin

include/multipass/cli/client_platform.h

@@ -33,6 +33,7 @@ void parse_copy_files_entry(const QString& entry, QString& path, QString& instan
 bool is_tty();
 int getuid();
 int getgid();
+void prepare_stdin_for_read();
 }
 }
 }

src/client/cmd/launch.cpp

@@ -90,7 +90,8 @@ mp::ParseCode cmd::Launch::parse_args(mp::ArgParser* parser)
     QCommandLineOption memOption({"m", "mem"}, "Amount of memory to allocate in bytes, or with K, M, G suffix", "mem",
                                  "1024"); // In MB's
     QCommandLineOption nameOption({"n", "name"}, "Name for the instance", "name");
-    QCommandLineOption cloudInitOption("cloud-init", "Path to a user-data cloud-init configuration", "file");
+    QCommandLineOption cloudInitOption("cloud-init", "Path to a user-data cloud-init configuration, or '-' for stdin",
+                                       "file");
     parser->addOptions({cpusOption, diskOption, memOption, nameOption, cloudInitOption});
 
     auto status = parser->commandParse(this);
@@ -160,7 +161,29 @@ mp::ParseCode cmd::Launch::parse_args(mp::ArgParser* parser)
     {
         try
         {
-            auto node = YAML::LoadFile(parser->value(cloudInitOption).toStdString());
+            YAML::Node node;
+            const QString& cloudInitFile = parser->value(cloudInitOption);
+            if (cloudInitFile == "-")
+            {
+                if (!mcp::is_tty())
+                {
+                    throw std::runtime_error("cannot read from stdin without a TTY");
+                }
+                mcp::prepare_stdin_for_read();
+                QByteArray content;
+                char arr[1024];
+                while (!std::cin.eof())
+                {
+                    std::cin.read(arr, sizeof(arr));
+                    int s = std::cin.gcount();
+                    content.append(arr, s);
+                }
+                node = YAML::Load(content.toStdString());
+            }
+            else
+            {
+                node = YAML::LoadFile(cloudInitFile.toStdString());
+            }
             request.set_cloud_init_user_data(YAML::Dump(node));
         }
         catch (const std::exception& e)

src/platform/client/client_platform.cpp

@@ -60,3 +60,8 @@ int mcp::getgid()
 {
     return ::getgid();
 }
+
+void mcp::prepare_stdin_for_read()
+{
+    // NO-OP
+}

tests/mock_stdcin.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2019 Canonical, Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef MULTIPASS_MOCK_STDCIN_H
+#define MULTIPASS_MOCK_STDCIN_H
+
+#include <iostream>
+#include <sstream>
+
+class MockStdCin
+{
+public:
+    MockStdCin(const std::string& s)
+    {
+        fake_cin << s;
+
+        // Backup and replace std::cin's streambuffer
+        cin_backup = std::cin.rdbuf();
+        std::streambuf* psbuf = fake_cin.rdbuf();
+        std::cin.rdbuf(psbuf); // assign streambuf to cin
+    }
+
+    ~MockStdCin()
+    {
+        // Restore cin's original streanbuffer
+        std::cin.rdbuf(cin_backup);
+    }
+
+private:
+    std::streambuf* cin_backup;
+    std::stringstream fake_cin;
+};
+
+#endif // MULTIPASS_MOCK_STDCIN_H

tests/test_cli_client.cpp

@@ -15,6 +15,7 @@
  *
  */
 
+#include "mock_stdcin.h"
 #include "path.h"
 #include "stub_cert_store.h"
 #include "stub_certprovider.h"
@@ -25,6 +26,7 @@
 
 #include <QEventLoop>
 #include <QStringList>
+#include <QTemporaryFile>
 
 #include <gmock/gmock.h>
 
@@ -204,6 +206,33 @@ TEST_F(Client, launch_cmd_custom_image_http_ok)
     EXPECT_THAT(send_command({"launch", "http://foo"}), Eq(mp::ReturnCode::Ok));
 }
 
+TEST_F(Client, launch_cmd_cloudinit_option_with_valid_file_is_ok)
+{
+    QTemporaryFile tmpfile; // file is auto-deleted when this goes out of scope
+    tmpfile.open();
+    tmpfile.write("password: passw0rd"); // need some YAML
+    tmpfile.close();
+    EXPECT_THAT(send_command({"launch", "--cloud-init", qPrintable(tmpfile.fileName())}), Eq(mp::ReturnCode::Ok));
+}
+
+TEST_F(Client, launch_cmd_cloudinit_option_with_missing_file)
+{
+    EXPECT_THAT(send_command({"launch", "--cloud-init", "/definitely/missing-file"}),
+                Eq(mp::ReturnCode::CommandLineError));
+}
+
+TEST_F(Client, launch_cmd_cloudinit_option_fails_no_value)
+{
+    EXPECT_THAT(send_command({"launch", "--cloud-init"}), Eq(mp::ReturnCode::CommandLineError));
+}
+
+TEST_F(Client, launch_cmd_cloudinit_option_reads_stdin_ok)
+{
+    MockStdCin cin("password: passw0rd");
+
+    EXPECT_THAT(send_command({"launch", "--cloud-init", "-"}), Eq(mp::ReturnCode::Ok));
+}
+
 // purge cli tests
 TEST_F(Client, empty_trash_cmd_ok_no_args)
 {