diff options
Diffstat (limited to 'runsc/config')
| -rw-r--r-- | runsc/config/config.go | 443 | ||||
| -rw-r--r-- | runsc/config/flags.go | 168 |
2 files changed, 367 insertions, 244 deletions
diff --git a/runsc/config/config.go b/runsc/config/config.go index 8cf0378d5..bca27ebf1 100644 --- a/runsc/config/config.go +++ b/runsc/config/config.go @@ -19,254 +19,105 @@ package config import ( "fmt" - "strconv" - "strings" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/watchdog" ) -// FileAccessType tells how the filesystem is accessed. -type FileAccessType int - -const ( - // FileAccessShared sends IO requests to a Gofer process that validates the - // requests and forwards them to the host. - FileAccessShared FileAccessType = iota - - // FileAccessExclusive is the same as FileAccessShared, but enables - // extra caching for improved performance. It should only be used if - // the sandbox has exclusive access to the filesystem. - FileAccessExclusive -) - -// MakeFileAccessType converts type from string. -func MakeFileAccessType(s string) (FileAccessType, error) { - switch s { - case "shared": - return FileAccessShared, nil - case "exclusive": - return FileAccessExclusive, nil - default: - return 0, fmt.Errorf("invalid file access type %q", s) - } -} - -func (f FileAccessType) String() string { - switch f { - case FileAccessShared: - return "shared" - case FileAccessExclusive: - return "exclusive" - default: - return fmt.Sprintf("unknown(%d)", f) - } -} - -// NetworkType tells which network stack to use. -type NetworkType int - -const ( - // NetworkSandbox uses internal network stack, isolated from the host. - NetworkSandbox NetworkType = iota - - // NetworkHost redirects network related syscalls to the host network. - NetworkHost - - // NetworkNone sets up just loopback using netstack. - NetworkNone -) - -// MakeNetworkType converts type from string. -func MakeNetworkType(s string) (NetworkType, error) { - switch s { - case "sandbox": - return NetworkSandbox, nil - case "host": - return NetworkHost, nil - case "none": - return NetworkNone, nil - default: - return 0, fmt.Errorf("invalid network type %q", s) - } -} - -func (n NetworkType) String() string { - switch n { - case NetworkSandbox: - return "sandbox" - case NetworkHost: - return "host" - case NetworkNone: - return "none" - default: - return fmt.Sprintf("unknown(%d)", n) - } -} - -// MakeWatchdogAction converts type from string. -func MakeWatchdogAction(s string) (watchdog.Action, error) { - switch strings.ToLower(s) { - case "log", "logwarning": - return watchdog.LogWarning, nil - case "panic": - return watchdog.Panic, nil - default: - return 0, fmt.Errorf("invalid watchdog action %q", s) - } -} - -// MakeRefsLeakMode converts type from string. -func MakeRefsLeakMode(s string) (refs.LeakMode, error) { - switch strings.ToLower(s) { - case "disabled": - return refs.NoLeakChecking, nil - case "log-names": - return refs.LeaksLogWarning, nil - case "log-traces": - return refs.LeaksLogTraces, nil - default: - return 0, fmt.Errorf("invalid refs leakmode %q", s) - } -} - -func refsLeakModeToString(mode refs.LeakMode) string { - switch mode { - // If not set, default it to disabled. - case refs.UninitializedLeakChecking, refs.NoLeakChecking: - return "disabled" - case refs.LeaksLogWarning: - return "log-names" - case refs.LeaksLogTraces: - return "log-traces" - default: - panic(fmt.Sprintf("Invalid leakmode: %d", mode)) - } -} - -// QueueingDiscipline is used to specify the kind of Queueing Discipline to -// apply for a give FDBasedLink. -type QueueingDiscipline int - -const ( - // QDiscNone disables any queueing for the underlying FD. - QDiscNone QueueingDiscipline = iota - - // QDiscFIFO applies a simple fifo based queue to the underlying - // FD. - QDiscFIFO -) - -// MakeQueueingDiscipline if possible the equivalent QueuingDiscipline for s -// else returns an error. -func MakeQueueingDiscipline(s string) (QueueingDiscipline, error) { - switch s { - case "none": - return QDiscNone, nil - case "fifo": - return QDiscFIFO, nil - default: - return 0, fmt.Errorf("unsupported qdisc specified: %q", s) - } -} - -// String implements fmt.Stringer. -func (q QueueingDiscipline) String() string { - switch q { - case QDiscNone: - return "none" - case QDiscFIFO: - return "fifo" - default: - panic(fmt.Sprintf("Invalid queueing discipline: %d", q)) - } -} - // Config holds configuration that is not part of the runtime spec. +// +// Follow these steps to add a new flag: +// 1. Create a new field in Config. +// 2. Add a field tag with the flag name +// 3. Register a new flag in flags.go, with name and description +// 4. Add any necessary validation into validate() +// 5. If adding an enum, follow the same pattern as FileAccessType +// type Config struct { // RootDir is the runtime root directory. - RootDir string + RootDir string `flag:"root"` // Debug indicates that debug logging should be enabled. - Debug bool + Debug bool `flag:"debug"` // LogFilename is the filename to log to, if not empty. - LogFilename string + LogFilename string `flag:"log"` // LogFormat is the log format. - LogFormat string + LogFormat string `flag:"log-format"` // DebugLog is the path to log debug information to, if not empty. - DebugLog string + DebugLog string `flag:"debug-log"` // PanicLog is the path to log GO's runtime messages, if not empty. - PanicLog string + PanicLog string `flag:"panic-log"` // DebugLogFormat is the log format for debug. - DebugLogFormat string + DebugLogFormat string `flag:"debug-log-format"` // FileAccess indicates how the filesystem is accessed. - FileAccess FileAccessType + FileAccess FileAccessType `flag:"file-access"` // Overlay is whether to wrap the root filesystem in an overlay. - Overlay bool + Overlay bool `flag:"overlay"` // FSGoferHostUDS enables the gofer to mount a host UDS. - FSGoferHostUDS bool + FSGoferHostUDS bool `flag:"fsgofer-host-uds"` // Network indicates what type of network to use. - Network NetworkType + Network NetworkType `flag:"network"` // EnableRaw indicates whether raw sockets should be enabled. Raw // sockets are disabled by stripping CAP_NET_RAW from the list of // capabilities. - EnableRaw bool + EnableRaw bool `flag:"net-raw"` // HardwareGSO indicates that hardware segmentation offload is enabled. - HardwareGSO bool + HardwareGSO bool `flag:"gso"` // SoftwareGSO indicates that software segmentation offload is enabled. - SoftwareGSO bool + SoftwareGSO bool `flag:"software-gso"` // TXChecksumOffload indicates that TX Checksum Offload is enabled. - TXChecksumOffload bool + TXChecksumOffload bool `flag:"tx-checksum-offload"` // RXChecksumOffload indicates that RX Checksum Offload is enabled. - RXChecksumOffload bool + RXChecksumOffload bool `flag:"rx-checksum-offload"` // QDisc indicates the type of queuening discipline to use by default // for non-loopback interfaces. - QDisc QueueingDiscipline + QDisc QueueingDiscipline `flag:"qdisc"` // LogPackets indicates that all network packets should be logged. - LogPackets bool + LogPackets bool `flag:"log-packets"` // Platform is the platform to run on. - Platform string + Platform string `flag:"platform"` // Strace indicates that strace should be enabled. - Strace bool + Strace bool `flag:"strace"` - // StraceSyscalls is the set of syscalls to trace. If StraceEnable is - // true and this list is empty, then all syscalls will be traced. - StraceSyscalls []string + // StraceSyscalls is the set of syscalls to trace (comma-separated values). + // If StraceEnable is true and this string is empty, then all syscalls will + // be traced. + StraceSyscalls string `flag:"strace-syscalls"` // StraceLogSize is the max size of data blobs to display. - StraceLogSize uint + StraceLogSize uint `flag:"strace-log-size"` // DisableSeccomp indicates whether seccomp syscall filters should be // disabled. Pardon the double negation, but default to enabled is important. DisableSeccomp bool // WatchdogAction sets what action the watchdog takes when triggered. - WatchdogAction watchdog.Action + WatchdogAction watchdog.Action `flag:"watchdog-action"` // PanicSignal registers signal handling that panics. Usually set to // SIGUSR2(12) to troubleshoot hangs. -1 disables it. - PanicSignal int + PanicSignal int `flag:"panic-signal"` // ProfileEnable is set to prepare the sandbox to be profiled. - ProfileEnable bool + ProfileEnable bool `flag:"profile"` // RestoreFile is the path to the saved container image RestoreFile string @@ -274,105 +125,209 @@ type Config struct { // NumNetworkChannels controls the number of AF_PACKET sockets that map // to the same underlying network device. This allows netstack to better // scale for high throughput use cases. - NumNetworkChannels int + NumNetworkChannels int `flag:"num-network-channels"` // Rootless allows the sandbox to be started with a user that is not root. // Defense is depth measures are weaker with rootless. Specifically, the // sandbox and Gofer process run as root inside a user namespace with root // mapped to the caller's user. - Rootless bool + Rootless bool `flag:"rootless"` // AlsoLogToStderr allows to send log messages to stderr. - AlsoLogToStderr bool + AlsoLogToStderr bool `flag:"alsologtostderr"` // ReferenceLeakMode sets reference leak check mode - ReferenceLeakMode refs.LeakMode + ReferenceLeak refs.LeakMode `flag:"ref-leak-mode"` // OverlayfsStaleRead instructs the sandbox to assume that the root mount // is on a Linux overlayfs mount, which does not necessarily preserve // coherence between read-only and subsequent writable file descriptors // representing the "same" file. - OverlayfsStaleRead bool + OverlayfsStaleRead bool `flag:"overlayfs-stale-read"` // CPUNumFromQuota sets CPU number count to available CPU quota, using // least integer value greater than or equal to quota. // // E.g. 0.2 CPU quota will result in 1, and 1.9 in 2. - CPUNumFromQuota bool + CPUNumFromQuota bool `flag:"cpu-num-from-quota"` - // Enables VFS2 (not plumbed through yet). - VFS2 bool + // Enables VFS2. + VFS2 bool `flag:"vfs2"` - // Enables FUSE usage (not plumbed through yet). - FUSE bool + // Enables FUSE usage. + FUSE bool `flag:"fuse"` // TestOnlyAllowRunAsCurrentUserWithoutChroot should only be used in // tests. It allows runsc to start the sandbox process as the current // user, and without chrooting the sandbox process. This can be // necessary in test environments that have limited capabilities. - TestOnlyAllowRunAsCurrentUserWithoutChroot bool + TestOnlyAllowRunAsCurrentUserWithoutChroot bool `flag:"TESTONLY-unsafe-nonroot"` // TestOnlyTestNameEnv should only be used in tests. It looks up for the // test name in the container environment variables and adds it to the debug // log file name. This is done to help identify the log with the test when // multiple tests are run in parallel, since there is no way to pass // parameters to the runtime from docker. - TestOnlyTestNameEnv string + TestOnlyTestNameEnv string `flag:"TESTONLY-test-name-env"` +} + +func (c *Config) validate() error { + if c.FileAccess == FileAccessShared && c.Overlay { + return fmt.Errorf("overlay flag is incompatible with shared file access") + } + if c.NumNetworkChannels <= 0 { + return fmt.Errorf("num_network_channels must be > 0, got: %d", c.NumNetworkChannels) + } + return nil } -// ToFlags returns a slice of flags that correspond to the given Config. -func (c *Config) ToFlags() []string { - f := []string{ - "--root=" + c.RootDir, - "--debug=" + strconv.FormatBool(c.Debug), - "--log=" + c.LogFilename, - "--log-format=" + c.LogFormat, - "--debug-log=" + c.DebugLog, - "--panic-log=" + c.PanicLog, - "--debug-log-format=" + c.DebugLogFormat, - "--file-access=" + c.FileAccess.String(), - "--overlay=" + strconv.FormatBool(c.Overlay), - "--fsgofer-host-uds=" + strconv.FormatBool(c.FSGoferHostUDS), - "--network=" + c.Network.String(), - "--log-packets=" + strconv.FormatBool(c.LogPackets), - "--platform=" + c.Platform, - "--strace=" + strconv.FormatBool(c.Strace), - "--strace-syscalls=" + strings.Join(c.StraceSyscalls, ","), - "--strace-log-size=" + strconv.Itoa(int(c.StraceLogSize)), - "--watchdog-action=" + c.WatchdogAction.String(), - "--panic-signal=" + strconv.Itoa(c.PanicSignal), - "--profile=" + strconv.FormatBool(c.ProfileEnable), - "--net-raw=" + strconv.FormatBool(c.EnableRaw), - "--num-network-channels=" + strconv.Itoa(c.NumNetworkChannels), - "--rootless=" + strconv.FormatBool(c.Rootless), - "--alsologtostderr=" + strconv.FormatBool(c.AlsoLogToStderr), - "--ref-leak-mode=" + refsLeakModeToString(c.ReferenceLeakMode), - "--gso=" + strconv.FormatBool(c.HardwareGSO), - "--software-gso=" + strconv.FormatBool(c.SoftwareGSO), - "--rx-checksum-offload=" + strconv.FormatBool(c.RXChecksumOffload), - "--tx-checksum-offload=" + strconv.FormatBool(c.TXChecksumOffload), - "--overlayfs-stale-read=" + strconv.FormatBool(c.OverlayfsStaleRead), - "--qdisc=" + c.QDisc.String(), - "--vfs2=" + strconv.FormatBool(c.VFS2), - "--fuse=" + strconv.FormatBool(c.FUSE), +// FileAccessType tells how the filesystem is accessed. +type FileAccessType int + +const ( + // FileAccessExclusive is the same as FileAccessShared, but enables + // extra caching for improved performance. It should only be used if + // the sandbox has exclusive access to the filesystem. + FileAccessExclusive FileAccessType = iota + + // FileAccessShared sends IO requests to a Gofer process that validates the + // requests and forwards them to the host. + FileAccessShared +) + +func fileAccessTypePtr(v FileAccessType) *FileAccessType { + return &v +} + +// Set implements flag.Value. +func (f *FileAccessType) Set(v string) error { + switch v { + case "shared": + *f = FileAccessShared + case "exclusive": + *f = FileAccessExclusive + default: + return fmt.Errorf("invalid file access type %q", v) } - if c.CPUNumFromQuota { - f = append(f, "--cpu-num-from-quota") + return nil +} + +// Get implements flag.Value. +func (f *FileAccessType) Get() interface{} { + return *f +} + +// String implements flag.Value. +func (f *FileAccessType) String() string { + switch *f { + case FileAccessShared: + return "shared" + case FileAccessExclusive: + return "exclusive" } - if c.VFS2 { - f = append(f, "--vfs2=true") + panic(fmt.Sprintf("Invalid file access type %v", *f)) +} + +// NetworkType tells which network stack to use. +type NetworkType int + +const ( + // NetworkSandbox uses internal network stack, isolated from the host. + NetworkSandbox NetworkType = iota + + // NetworkHost redirects network related syscalls to the host network. + NetworkHost + + // NetworkNone sets up just loopback using netstack. + NetworkNone +) + +func networkTypePtr(v NetworkType) *NetworkType { + return &v +} + +// Set implements flag.Value. +func (n *NetworkType) Set(v string) error { + switch v { + case "sandbox": + *n = NetworkSandbox + case "host": + *n = NetworkHost + case "none": + *n = NetworkNone + default: + return fmt.Errorf("invalid network type %q", v) } - if c.FUSE { - f = append(f, "--fuse=true") + return nil +} + +// Get implements flag.Value. +func (n *NetworkType) Get() interface{} { + return *n +} + +// String implements flag.Value. +func (n *NetworkType) String() string { + switch *n { + case NetworkSandbox: + return "sandbox" + case NetworkHost: + return "host" + case NetworkNone: + return "none" } + panic(fmt.Sprintf("Invalid network type %v", *n)) +} + +// QueueingDiscipline is used to specify the kind of Queueing Discipline to +// apply for a give FDBasedLink. +type QueueingDiscipline int - // Only include these if set since it is never to be used by users. - if c.TestOnlyAllowRunAsCurrentUserWithoutChroot { - f = append(f, "--TESTONLY-unsafe-nonroot=true") +const ( + // QDiscNone disables any queueing for the underlying FD. + QDiscNone QueueingDiscipline = iota + + // QDiscFIFO applies a simple fifo based queue to the underlying FD. + QDiscFIFO +) + +func queueingDisciplinePtr(v QueueingDiscipline) *QueueingDiscipline { + return &v +} + +// Set implements flag.Value. +func (q *QueueingDiscipline) Set(v string) error { + switch v { + case "none": + *q = QDiscNone + case "fifo": + *q = QDiscFIFO + default: + return fmt.Errorf("invalid qdisc %q", v) } - if len(c.TestOnlyTestNameEnv) != 0 { - f = append(f, "--TESTONLY-test-name-env="+c.TestOnlyTestNameEnv) + return nil +} + +// Get implements flag.Value. +func (q *QueueingDiscipline) Get() interface{} { + return *q +} + +// String implements flag.Value. +func (q *QueueingDiscipline) String() string { + switch *q { + case QDiscNone: + return "none" + case QDiscFIFO: + return "fifo" } + panic(fmt.Sprintf("Invalid qdisc %v", *q)) +} + +func leakModePtr(v refs.LeakMode) *refs.LeakMode { + return &v +} - return f +func watchdogActionPtr(v watchdog.Action) *watchdog.Action { + return &v } diff --git a/runsc/config/flags.go b/runsc/config/flags.go new file mode 100644 index 000000000..488a4b9fb --- /dev/null +++ b/runsc/config/flags.go @@ -0,0 +1,168 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package config + +import ( + "fmt" + "os" + "path/filepath" + "reflect" + "strconv" + + "gvisor.dev/gvisor/pkg/refs" + "gvisor.dev/gvisor/pkg/sentry/watchdog" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/runsc/flag" +) + +var registration sync.Once + +// This is the set of flags used to populate Config. +func RegisterFlags() { + registration.Do(func() { + // Although these flags are not part of the OCI spec, they are used by + // Docker, and thus should not be changed. + flag.String("root", "", "root directory for storage of container state.") + flag.String("log", "", "file path where internal debug information is written, default is stdout.") + flag.String("log-format", "text", "log format: text (default), json, or json-k8s.") + flag.Bool("debug", false, "enable debug logging.") + + // These flags are unique to runsc, and are used to configure parts of the + // system that are not covered by the runtime spec. + + // Debugging flags. + flag.String("debug-log", "", "additional location for logs. If it ends with '/', log files are created inside the directory with default names. The following variables are available: %TIMESTAMP%, %COMMAND%.") + flag.String("panic-log", "", "file path were panic reports and other Go's runtime messages are written.") + flag.Bool("log-packets", false, "enable network packet logging.") + flag.String("debug-log-format", "text", "log format: text (default), json, or json-k8s.") + flag.Bool("alsologtostderr", false, "send log messages to stderr.") + + // Debugging flags: strace related + flag.Bool("strace", false, "enable strace.") + flag.String("strace-syscalls", "", "comma-separated list of syscalls to trace. If --strace is true and this list is empty, then all syscalls will be traced.") + flag.Uint("strace-log-size", 1024, "default size (in bytes) to log data argument blobs.") + + // Flags that control sandbox runtime behavior. + flag.String("platform", "ptrace", "specifies which platform to use: ptrace (default), kvm.") + flag.Var(watchdogActionPtr(watchdog.LogWarning), "watchdog-action", "sets what action the watchdog takes when triggered: log (default), panic.") + flag.Int("panic-signal", -1, "register signal handling that panics. Usually set to SIGUSR2(12) to troubleshoot hangs. -1 disables it.") + flag.Bool("profile", false, "prepares the sandbox to use Golang profiler. Note that enabling profiler loosens the seccomp protection added to the sandbox (DO NOT USE IN PRODUCTION).") + flag.Bool("rootless", false, "it allows the sandbox to be started with a user that is not root. Sandbox and Gofer processes may run with same privileges as current user.") + flag.Var(leakModePtr(refs.NoLeakChecking), "ref-leak-mode", "sets reference leak check mode: disabled (default), log-names, log-traces.") + flag.Bool("cpu-num-from-quota", false, "set cpu number to cpu quota (least integer greater or equal to quota value, but not less than 2)") + + // Flags that control sandbox runtime behavior: FS related. + flag.Var(fileAccessTypePtr(FileAccessExclusive), "file-access", "specifies which filesystem to use for the root mount: exclusive (default), shared. Volume mounts are always shared.") + flag.Bool("overlay", false, "wrap filesystem mounts with writable overlay. All modifications are stored in memory inside the sandbox.") + flag.Bool("overlayfs-stale-read", true, "assume root mount is an overlay filesystem") + flag.Bool("fsgofer-host-uds", false, "allow the gofer to mount Unix Domain Sockets.") + flag.Bool("vfs2", false, "TEST ONLY; use while VFSv2 is landing. This uses the new experimental VFS layer.") + flag.Bool("fuse", false, "TEST ONLY; use while FUSE in VFSv2 is landing. This allows the use of the new experimental FUSE filesystem.") + + // Flags that control sandbox runtime behavior: network related. + flag.Var(networkTypePtr(NetworkSandbox), "network", "specifies which network to use: sandbox (default), host, none. Using network inside the sandbox is more secure because it's isolated from the host network.") + flag.Bool("net-raw", false, "enable raw sockets. When false, raw sockets are disabled by removing CAP_NET_RAW from containers (`runsc exec` will still be able to utilize raw sockets). Raw sockets allow malicious containers to craft packets and potentially attack the network.") + flag.Bool("gso", true, "enable hardware segmentation offload if it is supported by a network device.") + flag.Bool("software-gso", true, "enable software segmentation offload when hardware offload can't be enabled.") + flag.Bool("tx-checksum-offload", false, "enable TX checksum offload.") + flag.Bool("rx-checksum-offload", true, "enable RX checksum offload.") + flag.Var(queueingDisciplinePtr(QDiscFIFO), "qdisc", "specifies which queueing discipline to apply by default to the non loopback nics used by the sandbox.") + flag.Int("num-network-channels", 1, "number of underlying channels(FDs) to use for network link endpoints.") + + // Test flags, not to be used outside tests, ever. + flag.Bool("TESTONLY-unsafe-nonroot", false, "TEST ONLY; do not ever use! This skips many security measures that isolate the host from the sandbox.") + flag.String("TESTONLY-test-name-env", "", "TEST ONLY; do not ever use! Used for automated tests to improve logging.") + }) +} + +// NewFromFlags creates a new Config with values coming from command line flags. +func NewFromFlags() (*Config, error) { + conf := &Config{} + + obj := reflect.ValueOf(conf).Elem() + st := obj.Type() + for i := 0; i < st.NumField(); i++ { + f := st.Field(i) + name, ok := f.Tag.Lookup("flag") + if !ok { + // No flag set for this field. + continue + } + fl := flag.CommandLine.Lookup(name) + if fl == nil { + panic(fmt.Sprintf("Flag %q not found", name)) + } + x := reflect.ValueOf(flag.Get(fl.Value)) + obj.Field(i).Set(x) + } + + if len(conf.RootDir) == 0 { + // If not set, set default root dir to something (hopefully) user-writeable. + conf.RootDir = "/var/run/runsc" + if runtimeDir := os.Getenv("XDG_RUNTIME_DIR"); runtimeDir != "" { + conf.RootDir = filepath.Join(runtimeDir, "runsc") + } + } + + if err := conf.validate(); err != nil { + return nil, err + } + return conf, nil +} + +// ToFlags returns a slice of flags that correspond to the given Config. +func (c *Config) ToFlags() []string { + var rv []string + + obj := reflect.ValueOf(c).Elem() + st := obj.Type() + for i := 0; i < st.NumField(); i++ { + f := st.Field(i) + name, ok := f.Tag.Lookup("flag") + if !ok { + // No flag set for this field. + continue + } + val := getVal(obj.Field(i)) + + flag := flag.CommandLine.Lookup(name) + if flag == nil { + panic(fmt.Sprintf("Flag %q not found", name)) + } + if val == flag.DefValue { + continue + } + rv = append(rv, fmt.Sprintf("--%s=%s", flag.Name, val)) + } + return rv +} + +func getVal(field reflect.Value) string { + if str, ok := field.Addr().Interface().(fmt.Stringer); ok { + return str.String() + } + switch field.Kind() { + case reflect.Bool: + return strconv.FormatBool(field.Bool()) + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return strconv.FormatInt(field.Int(), 10) + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return strconv.FormatUint(field.Uint(), 10) + case reflect.String: + return field.String() + default: + panic("unknown type " + field.Kind().String()) + } +} |