refactor(tests): always check ssh output

Ssh connection failure should be considered an error by default. In order
to unify handling of this case, move check for non zero return code
into the function itself. Because of this `check_output` method is
not needed anymore and was removed.

Signed-off-by: Egor Lazarchuk <[email protected]>

sq

Signed-off-by: Egor Lazarchuk <[email protected]>

tests/framework/microvm.py

@@ -1003,14 +1003,13 @@ def thread_backtraces(self):
                 )
         return "\n".join(backtraces)
 
-    def _dump_debug_information(self, exc: Exception):
+    def _dump_debug_information(self):
         """
         Dumps debug information about this microvm
 
         Used for example when running a command inside the guest via `SSHConnection.check_output` fails.
         """
         print(
-            f"Failure executing command via SSH in microVM: {exc}\n\n"
             f"Firecracker logs:\n{self.log_data}\n"
             f"Thread backtraces:\n{self.thread_backtraces}"
         )

tests/framework/utils.py

@@ -350,8 +350,7 @@ def get_free_mem_ssh(ssh_connection):
     :param ssh_connection: connection to the guest
     :return: available mem column output of 'free'
     """
-    _, stdout, stderr = ssh_connection.run("cat /proc/meminfo | grep MemAvailable")
-    assert stderr == ""
+    _, stdout, _ = ssh_connection.run("cat /proc/meminfo | grep MemAvailable")
 
     # Split "MemAvailable:   123456 kB" and validate it
     meminfo_data = stdout.split()
@@ -625,8 +624,7 @@ def guest_run_fio_iteration(ssh_connection, iteration):
         --output /tmp/fio{} > /dev/null &""".format(
         iteration
     )
-    exit_code, _, stderr = ssh_connection.run(fio)
-    assert exit_code == 0, stderr
+    ssh_connection.run(fio)
 
 
 def check_filesystem(ssh_connection, disk_fmt, disk):

tests/framework/utils_iperf.py

@@ -119,7 +119,7 @@ def spawn_iperf3_client(self, client_idx, client_mode_flag):
             .build()
         )
 
-        return self._microvm.ssh.check_output(cmd).stdout
+        return self._microvm.ssh.run(cmd).stdout
 
     def host_command(self, port_offset):
         """Builds the command used for spawning an iperf3 server on the host"""

tests/framework/utils_vsock.py

@@ -100,7 +100,7 @@ def start_guest_echo_server(vm):
     Returns a UDS path to connect to the server.
     """
     cmd = f"nohup socat VSOCK-LISTEN:{ECHO_SERVER_PORT},backlog=128,reuseaddr,fork EXEC:'/bin/cat' > /dev/null 2>&1 &"
-    vm.ssh.check_output(cmd)
+    vm.ssh.run(cmd)
 
     # Give the server time to initialise
     time.sleep(1)
@@ -214,8 +214,7 @@ def _copy_vsock_data_to_guest(ssh_connection, blob_path, vm_blob_path, vsock_hel
     # Copy the data file and a vsock helper to the guest.
 
     cmd = "mkdir -p /tmp/vsock"
-    ecode, _, _ = ssh_connection.run(cmd)
-    assert ecode == 0, "Failed to set up tmpfs drive on the guest."
+    ssh_connection.run(cmd)
 
     ssh_connection.scp_put(vsock_helper, "/tmp/vsock_helper")
     ssh_connection.scp_put(blob_path, vm_blob_path)

tests/host_tools/network.py

@@ -79,7 +79,7 @@ def remote_path(self, path):
 
     def _scp(self, path1, path2, options):
         """Copy files to/from the VM using scp."""
-        self._exec(["scp", *options, path1, path2], check=True)
+        self._exec(["scp", *options, path1, path2])
 
     def scp_put(self, local_path, remote_path, recursive=False):
         """Copy files to the VM using scp."""
@@ -111,9 +111,10 @@ def _init_connection(self):
         """
         self.check_output("true", timeout=100, debug=True)
 
-    def run(self, cmd_string, timeout=None, *, check=False, debug=False):
+    def run(self, cmd_string, timeout=None, *, check=True, debug=False):
         """
         Execute the command passed as a string in the ssh context.
+        By default raises an exception on non-zero return code of remote command.
 
         If `debug` is set, pass `-vvv` to `ssh`. Note that this will clobber stderr.
         """
@@ -124,22 +125,29 @@ def run(self, cmd_string, timeout=None, *, check=False, debug=False):
 
         return self._exec(command, timeout, check=check)
 
-    def check_output(self, cmd_string, timeout=None, *, debug=False):
-        """Same as `run`, but raises an exception on non-zero return code of remote command"""
-        return self.run(cmd_string, timeout, check=True, debug=debug)
-
-    def _exec(self, cmd, timeout=None, check=False):
+    def _exec(self, cmd, timeout=None, check=True):
         """Private function that handles the ssh client invocation."""
         if self.netns is not None:
             cmd = ["ip", "netns", "exec", self.netns] + cmd
 
-        try:
-            return utils.run_cmd(cmd, check=check, timeout=timeout)
-        except Exception as exc:
+        rc, stdout, stderr = utils.run_cmd(cmd, timeout=timeout)
+
+        if not check:
+            return rc, stdout, stderr
+
+        if rc != 0:
+            print(
+                f"SSH command {cmd} exited with non zero error code: {rc}\n"
+                f"stdout: {stdout}\n"
+                f"stderr: {stderr}\n"
+            )
+
             if self._on_error:
-                self._on_error(exc)
+                self._on_error()
 
-            raise
+            assert False
+
+        return rc, stdout, stderr
 
     # pylint:disable=invalid-name
     def Popen(

tests/integration_tests/functional/test_balloon.py

@@ -41,23 +41,11 @@ def get_rss_from_pmap():
 
 def lower_ssh_oom_chance(ssh_connection):
     """Lure OOM away from ssh process"""
-    logger = logging.getLogger("lower_ssh_oom_chance")
-
     cmd = "cat /run/sshd.pid"
-    exit_code, stdout, stderr = ssh_connection.run(cmd)
-    # add something to the logs for troubleshooting
-    if exit_code != 0:
-        logger.error("while running: %s", cmd)
-        logger.error("stdout: %s", stdout)
-        logger.error("stderr: %s", stderr)
-
+    _, stdout, _ = ssh_connection.run(cmd)
     for pid in stdout.split(" "):
         cmd = f"choom -n -1000 -p {pid}"
-        exit_code, stdout, stderr = ssh_connection.run(cmd)
-        if exit_code != 0:
-            logger.error("while running: %s", cmd)
-            logger.error("stdout: %s", stdout)
-            logger.error("stderr: %s", stderr)
+        ssh_connection.run(cmd)
 
 
 def make_guest_dirty_memory(ssh_connection, amount_mib=32):
@@ -68,12 +56,7 @@ def make_guest_dirty_memory(ssh_connection, amount_mib=32):
 
     cmd = f"/usr/local/bin/fillmem {amount_mib}"
     try:
-        exit_code, stdout, stderr = ssh_connection.run(cmd, timeout=1.0)
-        # add something to the logs for troubleshooting
-        if exit_code != 0:
-            logger.error("while running: %s", cmd)
-            logger.error("stdout: %s", stdout)
-            logger.error("stderr: %s", stderr)
+        ssh_connection.run(cmd, timeout=1.0)
     except TimeoutExpired:
         # It's ok if this expires. Sometimes the SSH connection
         # gets killed by the OOM killer *after* the fillmem program
@@ -558,4 +541,4 @@ def test_memory_scrub(microvm_factory, guest_kernel, rootfs):
     # Wait for the deflate to complete.
     _ = get_stable_rss_mem_by_pid(firecracker_pid)
 
-    microvm.ssh.check_output("/usr/local/bin/readmem {} {}".format(60, 1))
+    microvm.ssh.run("/usr/local/bin/readmem {} {}".format(60, 1))

tests/integration_tests/functional/test_cpu_features_aarch64.py

@@ -51,7 +51,7 @@ def _check_cpu_features_arm(test_microvm, guest_kv, template_name=None):
         case CpuModel.ARM_NEOVERSE_V1, _, None:
             expected_cpu_features = DEFAULT_G3_FEATURES_5_10
 
-    _, stdout, _ = test_microvm.ssh.check_output(CPU_FEATURES_CMD)
+    _, stdout, _ = test_microvm.ssh.run(CPU_FEATURES_CMD)
     flags = set(stdout.strip().split(" "))
     assert flags == expected_cpu_features
 
@@ -77,7 +77,7 @@ def test_host_vs_guest_cpu_features_aarch64(uvm_nano):
     vm.add_net_iface()
     vm.start()
     host_feats = set(utils.check_output(CPU_FEATURES_CMD).stdout.strip().split(" "))
-    guest_feats = set(vm.ssh.check_output(CPU_FEATURES_CMD).stdout.strip().split(" "))
+    guest_feats = set(vm.ssh.run(CPU_FEATURES_CMD).stdout.strip().split(" "))
 
     cpu_model = cpuid_utils.get_cpu_model_name()
     match cpu_model:

tests/integration_tests/functional/test_cpu_features_x86_64.py

@@ -215,7 +215,7 @@ def test_host_vs_guest_cpu_features_x86_64(uvm_nano):
     vm.add_net_iface()
     vm.start()
     host_feats = set(utils.check_output(CPU_FEATURES_CMD).stdout.strip().split(" "))
-    guest_feats = set(vm.ssh.check_output(CPU_FEATURES_CMD).stdout.strip().split(" "))
+    guest_feats = set(vm.ssh.run(CPU_FEATURES_CMD).stdout.strip().split(" "))
 
     cpu_model = cpuid_utils.get_cpu_codename()
     match cpu_model:

tests/integration_tests/functional/test_drive_vhost_user.py

@@ -15,8 +15,7 @@ def _check_block_size(ssh_connection, dev_path, size):
     """
     Checks the size of the block device.
     """
-    _, stdout, stderr = ssh_connection.run("blockdev --getsize64 {}".format(dev_path))
-    assert stderr == ""
+    _, stdout, _ = ssh_connection.run("blockdev --getsize64 {}".format(dev_path))
     assert stdout.strip() == str(size)
 
 
@@ -297,7 +296,7 @@ def test_config_change(microvm_factory, guest_kernel, rootfs):
     _check_block_size(vm.ssh, "/dev/vdb", orig_size * 1024 * 1024)
 
     # Check that we can create a filesystem and mount it
-    vm.ssh.check_output(mkfs_mount_cmd)
+    vm.ssh.run(mkfs_mount_cmd)
 
     for new_size in new_sizes:
         # Instruct the backend to resize the device.
@@ -312,4 +311,4 @@ def test_config_change(microvm_factory, guest_kernel, rootfs):
         _check_block_size(vm.ssh, "/dev/vdb", new_size * 1024 * 1024)
 
         # Check that we can create a filesystem and mount it
-        vm.ssh.check_output(mkfs_mount_cmd)
+        vm.ssh.run(mkfs_mount_cmd)

tests/integration_tests/functional/test_drive_virtio.py

@@ -283,7 +283,7 @@ def test_patch_drive(uvm_plain_any, io_engine):
     # of the device, in bytes.
     blksize_cmd = "LSBLK_DEBUG=all lsblk -b /dev/vdb --output SIZE"
     size_bytes_str = "536870912"  # = 512 MiB
-    _, stdout, _ = test_microvm.ssh.check_output(blksize_cmd)
+    _, stdout, _ = test_microvm.ssh.run(blksize_cmd)
     lines = stdout.split("\n")
     # skip "SIZE"
     assert lines[1].strip() == size_bytes_str
@@ -354,14 +354,12 @@ def test_flush(uvm_plain_rw, io_engine):
 
 
 def _check_block_size(ssh_connection, dev_path, size):
-    _, stdout, stderr = ssh_connection.run("blockdev --getsize64 {}".format(dev_path))
-    assert stderr == ""
+    _, stdout, _ = ssh_connection.run("blockdev --getsize64 {}".format(dev_path))
     assert stdout.strip() == str(size)
 
 
 def _check_file_size(ssh_connection, dev_path, size):
-    _, stdout, stderr = ssh_connection.run("stat --format=%s {}".format(dev_path))
-    assert stderr == ""
+    _, stdout, _ = ssh_connection.run("stat --format=%s {}".format(dev_path))
     assert stdout.strip() == str(size)
 
 
@@ -379,7 +377,5 @@ def _check_drives(test_microvm, assert_dict, keys_array):
 
 
 def _check_mount(ssh_connection, dev_path):
-    _, _, stderr = ssh_connection.run(f"mount {dev_path} /tmp", timeout=30.0)
-    assert stderr == ""
-    _, _, stderr = ssh_connection.run("umount /tmp", timeout=30.0)
-    assert stderr == ""
+    ssh_connection.run(f"mount {dev_path} /tmp", timeout=30.0)
+    ssh_connection.run("umount /tmp", timeout=30.0)

tests/integration_tests/functional/test_kvm_ptp.py

@@ -18,7 +18,7 @@ def test_kvm_ptp(uvm_plain_any):
     vm.add_net_iface()
     vm.start()
 
-    vm.ssh.check_output("[ -c /dev/ptp0 ]")
+    vm.ssh.run("[ -c /dev/ptp0 ]")
 
     # phc_ctl[14515.127]: clock time is 1697545854.728335694 or Tue Oct 17 12:30:54 2023
-    vm.ssh.check_output("phc_ctl /dev/ptp0 -- get")
+    vm.ssh.run("phc_ctl /dev/ptp0 -- get")

tests/integration_tests/functional/test_net.py

@@ -37,7 +37,7 @@ def test_high_ingress_traffic(uvm_plain_any):
     test_microvm.start()
 
     # Start iperf3 server on the guest.
-    test_microvm.ssh.check_output("{} -sD\n".format(IPERF_BINARY_GUEST))
+    test_microvm.ssh.run("{} -sD\n".format(IPERF_BINARY_GUEST))
     time.sleep(1)
 
     # Start iperf3 client on the host. Send 1Gbps UDP traffic.
@@ -53,7 +53,7 @@ def test_high_ingress_traffic(uvm_plain_any):
     # Check if the high ingress traffic broke the net interface.
     # If the net interface still works we should be able to execute
     # ssh commands.
-    test_microvm.ssh.check_output("echo success\n")
+    test_microvm.ssh.run("echo success\n")
 
 
 def test_multi_queue_unsupported(uvm_plain):
@@ -97,8 +97,8 @@ def run_udp_offload_test(vm):
     message = "x"
 
     # Start a UDP server in the guest
-    # vm.ssh.check_output(f"nohup socat UDP-LISTEN:{port} - > {out_filename} &")
-    vm.ssh.check_output(
+    # vm.ssh.run(f"nohup socat UDP-LISTEN:{port} - > {out_filename} &")
+    vm.ssh.run(
         f"nohup socat UDP4-LISTEN:{port} OPEN:{out_filename},creat > /dev/null 2>&1 &"
     )
 

tests/integration_tests/functional/test_net_config_space.py

@@ -219,8 +219,7 @@ def _find_iomem_range(ssh_connection, dev_name):
     # its contents and grep for the VirtIO device name, which
     # with ACPI is "LNRO0005:XY".
     cmd = f"cat /proc/iomem | grep -m 1 {dev_name}"
-    rc, stdout, stderr = ssh_connection.run(cmd)
-    assert rc == 0, stderr
+    _, stdout, _ = ssh_connection.run(cmd)
 
     # Take range in the form 'start-end' from line. The line looks like this:
     # d00002000-d0002fff : LNRO0005:02
@@ -259,8 +258,7 @@ def _get_net_mem_addr_base_x86_cmdline(ssh_connection, if_name):
     """Check for net device memory start address via command line arguments"""
     sys_virtio_mmio_cmdline = "/sys/devices/virtio-mmio-cmdline/"
     cmd = "ls {} | grep virtio-mmio. | sed 's/virtio-mmio.//'"
-    exit_code, stdout, stderr = ssh_connection.run(cmd.format(sys_virtio_mmio_cmdline))
-    assert exit_code == 0, stderr
+    _, stdout, _ = ssh_connection.run(cmd.format(sys_virtio_mmio_cmdline))
     virtio_devs_idx = stdout.strip().split()
 
     cmd = "cat /proc/cmdline"
@@ -299,8 +297,7 @@ def _get_net_mem_addr_base(ssh_connection, if_name):
     if platform.machine() == "aarch64":
         sys_virtio_mmio_cmdline = "/sys/devices/platform"
         cmd = "ls {} | grep .virtio_mmio".format(sys_virtio_mmio_cmdline)
-        rc, stdout, _ = ssh_connection.run(cmd)
-        assert rc == 0
+        _, stdout, _ = ssh_connection.run(cmd)
 
         virtio_devs = stdout.split()
         devs_addr = list(map(lambda dev: dev.split(".")[0], virtio_devs))

tests/integration_tests/functional/test_pause_resume.py

@@ -53,15 +53,15 @@ def test_pause_resume(uvm_nano):
 
     # Verify guest is no longer active.
     with pytest.raises(ChildProcessError):
-        microvm.ssh.check_output("true")
+        microvm.ssh.run("true")
 
     # Verify emulation was indeed paused and no events from either
     # guest or host side were handled.
     verify_net_emulation_paused(microvm.flush_metrics())
 
     # Verify guest is no longer active.
     with pytest.raises(ChildProcessError):
-        microvm.ssh.check_output("true")
+        microvm.ssh.run("true")
 
     # Pausing the microVM when it is already `Paused` is allowed
     # (microVM remains in `Paused` state).
@@ -152,7 +152,7 @@ def test_kvmclock_ctrl(uvm_plain_any):
     # console. This detail is important as it writing in the console seems to increase the probability
     # that we will pause the execution inside the kernel and cause a lock up. Setting KVM_CLOCK_CTRL
     # bit that informs the guest we're pausing the vCPUs, should avoid that lock up.
-    microvm.ssh.check_output(
+    microvm.ssh.run(
         "timeout 60 sh -c 'while true; do ls -R /; done' > /dev/ttyS0 2>&1 < /dev/null &"
     )
 
@@ -161,7 +161,7 @@ def test_kvmclock_ctrl(uvm_plain_any):
         time.sleep(5)
         microvm.api.vm.patch(state="Resumed")
 
-    dmesg = microvm.ssh.check_output("dmesg").stdout
+    dmesg = microvm.ssh.run("dmesg").stdout
     assert "rcu_sched self-detected stall on CPU" not in dmesg
     assert "rcu_preempt detected stalls on CPUs/tasks" not in dmesg
     assert "BUG: soft lockup -" not in dmesg

tests/integration_tests/functional/test_rng.py

@@ -150,7 +150,7 @@ def _get_throughput(ssh, random_bytes):
     # Issue a `dd` command to request 100 times `random_bytes` from the device.
     # 100 here is used to get enough confidence on the achieved throughput.
     cmd = "dd if=/dev/hwrng of=/dev/null bs={} count=100".format(random_bytes)
-    _, _, stderr = ssh.check_output(cmd)
+    _, _, stderr = ssh.run(cmd)
 
     # dd gives its output on stderr
     return _process_dd_output(stderr)

tests/integration_tests/functional/test_serial_io.py

@@ -188,15 +188,13 @@ def test_serial_block(uvm_plain_any):
     os.kill(test_microvm.screen_pid, signal.SIGSTOP)
 
     # Generate a random text file.
-    test_microvm.ssh.check_output(
-        "base64 /dev/urandom | head -c 100000 > /tmp/file.txt"
-    )
+    test_microvm.ssh.run("base64 /dev/urandom | head -c 100000 > /tmp/file.txt")
 
     # Dump output to terminal
-    test_microvm.ssh.check_output("cat /tmp/file.txt > /dev/ttyS0")
+    test_microvm.ssh.run("cat /tmp/file.txt > /dev/ttyS0")
 
     # Check that the vCPU isn't blocked.
-    test_microvm.ssh.check_output("cd /")
+    test_microvm.ssh.run("cd /")
 
     # Check the metrics to see if the serial missed bytes.
     fc_metrics = test_microvm.flush_metrics()