NewInspector Interface enforces sanity across Interface initializers

driver/ssh.go

@@ -27,7 +27,8 @@ type SSH struct {
 	// Check known hosts (only disable for tests
 	CheckKnownHosts bool
 	// set environmental vars for server e.g []string{"DEBUG=1", "FAKE=echo"}
-	Vars []string
+	Vars          []string
+	SessionClient *goph.Client
 }
 
 func (d *SSH) String() string {
@@ -36,33 +37,37 @@ func (d *SSH) String() string {
 
 // set the goph Client
 func (d *SSH) Client() (*goph.Client, error) {
-	var err error
-	var client *goph.Client
-	var callback ssh.HostKeyCallback
-	if d.Port != 0 {
-		port = d.Port
-	}
-	auth, err := goph.Key(d.KeyFile, d.KeyPass)
-	if err != nil {
-		return nil, err
-	}
-	if d.CheckKnownHosts {
-		callback, err = goph.DefaultKnownHosts()
+	if d.SessionClient == nil {
+		var err error
+		var client *goph.Client
+		var callback ssh.HostKeyCallback
+		if d.Port != 0 {
+			port = d.Port
+		}
+		auth, err := goph.Key(d.KeyFile, d.KeyPass)
 		if err != nil {
 			return nil, err
 		}
-	} else {
-		callback = ssh.InsecureIgnoreHostKey()
+		if d.CheckKnownHosts {
+			callback, err = goph.DefaultKnownHosts()
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			callback = ssh.InsecureIgnoreHostKey()
+		}
+		client, err = goph.NewConn(&goph.Config{
+			User:     d.User,
+			Addr:     d.Host,
+			Port:     uint(port),
+			Auth:     auth,
+			Timeout:  goph.DefaultTimeout,
+			Callback: callback,
+		})
+		d.SessionClient = client
+		return client, err
 	}
-	client, err = goph.NewConn(&goph.Config{
-		User:     d.User,
-		Addr:     d.Host,
-		Port:     uint(port),
-		Auth:     auth,
-		Timeout:  goph.DefaultTimeout,
-		Callback: callback,
-	})
-	return client, err
+	return d.SessionClient, nil
 }
 
 func (d *SSH) ReadFile(path string) (string, error) {
@@ -72,7 +77,7 @@ func (d *SSH) ReadFile(path string) (string, error) {
 }
 
 func (d *SSH) RunCommand(command string) (string, error) {
-	// FIXME: Do we retain client across all command runs?
+	// FIXME: provide refresh interface to somehow refresh d.Client if d.SessionClient somehow gets dropped
 	log.Debugf("Running remote command %s", command)
 	client, err := d.Client()
 	if err != nil {
@@ -112,8 +117,6 @@ func (d *SSH) GetDetails() SystemDetails {
 			details.IsLinux = true
 		case "darwin":
 			details.IsDarwin = true
-		default:
-			details.IsLinux = true
 		}
 		d.Info = details
 	}

inspector/custom.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/bisohns/saido/driver"
@@ -51,15 +52,15 @@ func (i *Custom) Execute() {
 }
 
 // NewCustom : Initialize a new Custom instance
-func NewCustom(custom string, driver *driver.Driver) Inspector {
+func NewCustom(driver *driver.Driver, custom ...string) (Inspector, error) {
 	var customInspector Inspector
 	details := (*driver).GetDetails()
 	if details.IsWeb {
-		panic(fmt.Sprintf("Cannot use Custom(%s) on web", custom))
+		return nil, errors.New(fmt.Sprintf("Cannot use Custom(%s) on web", custom))
 	}
 	customInspector = &Custom{
-		Command: custom,
+		Command: custom[0],
 	}
 	customInspector.SetDriver(driver)
-	return customInspector
+	return customInspector, nil
 }

inspector/disk.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"strconv"
 	"strings"
 
@@ -97,11 +98,11 @@ type WMIC struct {
 }
 
 // NewDF : Initialize a new DF instance
-func NewDF(driver *driver.Driver) Inspector {
+func NewDF(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var df Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsLinux || details.IsDarwin || details.IsWindows) {
-		panic("Cannot use 'df' command on drivers outside (linux, darwin, windows)")
+		return nil, errors.New("Cannot use 'df' command on drivers outside (linux, darwin, windows)")
 	}
 	if details.IsLinux || details.IsDarwin {
 		df = &DF{
@@ -114,5 +115,5 @@ func NewDF(driver *driver.Driver) Inspector {
 		}
 	}
 	df.SetDriver(driver)
-	return df
+	return df, nil
 }

inspector/disk_test.go

@@ -21,7 +21,7 @@ func NewSSHForTest() driver.Driver {
 
 func TestDFOnLocal(t *testing.T) {
 	driver := NewLocalForTest()
-	d := NewDF(&driver)
+	d, _ := NewDF(&driver)
 	d.Execute()
 	dfConcrete, _ := d.(*DF)
 	if len(dfConcrete.Values) == 0 {
@@ -31,7 +31,7 @@ func TestDFOnLocal(t *testing.T) {
 
 func TestDFOnSSH(t *testing.T) {
 	driver := NewSSHForTest()
-	d := NewDF(&driver)
+	d, _ := NewDF(&driver)
 	d.Execute()
 	dfConcrete, _ := d.(*DF)
 	if len(dfConcrete.Values) == 0 {

inspector/docker_stats.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"strconv"
 	"strings"
 
@@ -109,15 +110,15 @@ func (i *DockerStats) Execute() {
 }
 
 // NewDockerStats : Initialize a new DockerStats instance
-func NewDockerStats(driver *driver.Driver) Inspector {
+func NewDockerStats(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var dockerstats Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsLinux || details.IsDarwin || details.IsWindows) {
-		panic("Cannot use LoadAvgDarwin on drivers outside (linux, darwin, windows)")
+		return nil, errors.New("Cannot use LoadAvgDarwin on drivers outside (linux, darwin, windows)")
 	}
 	dockerstats = &DockerStats{
 		Command: `docker stats --no-stream`,
 	}
 	dockerstats.SetDriver(driver)
-	return dockerstats
+	return dockerstats, nil
 }

inspector/inspector.go

@@ -1,6 +1,9 @@
 package inspector
 
 import (
+	"errors"
+	"fmt"
+
 	"github.com/bisohns/saido/driver"
 )
 
@@ -11,3 +14,28 @@ type Inspector interface {
 	Execute()
 	driverExec() driver.Command
 }
+
+type NewInspector func(driver *driver.Driver, custom ...string) (Inspector, error)
+
+var inspectorMap = map[string]NewInspector{
+	`disk`:         NewDF,
+	`docker`:       NewDockerStats,
+	`uptime`:       NewUptime,
+	`responsetime`: NewResponseTime,
+	`memory`:       NewMemInfo,
+	`process`:      NewProcess,
+	`custom`:       NewCustom,
+}
+
+// Init : initializes the specified inspector using name and driver
+func Init(name string, driver *driver.Driver, custom ...string) (Inspector, error) {
+	val, ok := inspectorMap[name]
+	if ok {
+		inspector, err := val(driver, custom...)
+		if err != nil {
+			return nil, err
+		}
+		return inspector, nil
+	}
+	return nil, errors.New(fmt.Sprintf("Cannot find inspector with name %s", name))
+}

inspector/loadavg.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"strconv"
 	"strings"
 
@@ -98,11 +99,11 @@ func (i *LoadAvg) Execute() {
 // of LoadAvg
 
 // NewLoadAvg : Initialize a new LoadAvg instance
-func NewLoadAvg(driver *driver.Driver) Inspector {
+func NewLoadAvg(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var loadavg Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsLinux || details.IsDarwin) {
-		panic("Cannot use LoadAvg on drivers outside (linux, darwin)")
+		return nil, errors.New("Cannot use LoadAvg on drivers outside (linux, darwin)")
 	}
 	if details.IsLinux {
 		loadavg = &LoadAvg{
@@ -115,6 +116,6 @@ func NewLoadAvg(driver *driver.Driver) Inspector {
 		}
 	}
 	loadavg.SetDriver(driver)
-	return loadavg
+	return loadavg, nil
 
 }

inspector/loadavg_unix_test.go

@@ -14,7 +14,7 @@ func NewLocalForTest() driver.Driver {
 
 func TestLoadAvg(t *testing.T) {
 	testDriver := NewLocalForTest()
-	loadavg := NewLoadAvg(&testDriver)
+	loadavg, _ := NewLoadAvg(&testDriver)
 	loadavg.Execute()
 	loadavgConcreteLinux, ok := loadavg.(*LoadAvg)
 	if ok {

inspector/meminfo.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -166,11 +167,11 @@ func (i *MemInfoDarwin) Execute() {
 // TODO: Windows Equivalents of MemInfo
 
 // NewMemInfoLinux : Initialize a new MemInfoLinux instance
-func NewMemInfo(driver *driver.Driver) Inspector {
+func NewMemInfo(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var meminfo Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsLinux || details.IsDarwin) {
-		panic("Cannot use MemInfo on drivers outside (linux, darwin)")
+		return nil, errors.New("Cannot use MemInfo on drivers outside (linux, darwin)")
 	}
 	if details.IsLinux {
 		meminfo = &MemInfoLinux{
@@ -187,5 +188,5 @@ func NewMemInfo(driver *driver.Driver) Inspector {
 		}
 	}
 	meminfo.SetDriver(driver)
-	return meminfo
+	return meminfo, nil
 }

inspector/meminfo_test.go

@@ -8,7 +8,7 @@ import (
 
 func TestMemInfoOnLocal(t *testing.T) {
 	driver := NewLocalForTest()
-	d := NewMemInfo(&driver)
+	d, _ := NewMemInfo(&driver)
 	d.Execute()
 	iConcreteLinux, ok := d.(*MemInfoLinux)
 	if ok {

inspector/process.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"strconv"
 	"strings"
 
@@ -185,11 +186,11 @@ func (i *ProcessWin) Execute() {
 }
 
 // NewProcess : Initialize a new Process instance
-func NewProcess(driver *driver.Driver) Inspector {
+func NewProcess(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var process Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsLinux || details.IsDarwin || details.IsWindows) {
-		panic("Cannot use Process on drivers outside (linux, darwin, windows)")
+		return nil, errors.New("Cannot use Process on drivers outside (linux, darwin, windows)")
 	}
 	if details.IsLinux || details.IsDarwin {
 		process = &Process{
@@ -201,5 +202,5 @@ func NewProcess(driver *driver.Driver) Inspector {
 		}
 	}
 	process.SetDriver(driver)
-	return process
+	return process, nil
 }

inspector/rt.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"strconv"
 
 	"github.com/bisohns/saido/driver"
@@ -49,15 +50,15 @@ func (i *ResponseTime) Execute() {
 }
 
 // NewResponseTime : Initialize a new ResponseTime instance
-func NewResponseTime(driver *driver.Driver) Inspector {
+func NewResponseTime(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var responsetime Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsWeb) {
-		panic("Cannot use response time outside driver (web)")
+		return nil, errors.New("Cannot use response time outside driver (web)")
 	}
 	responsetime = &ResponseTime{
 		Command: `response`,
 	}
 	responsetime.SetDriver(driver)
-	return responsetime
+	return responsetime, nil
 }

inspector/uptime.go

@@ -1,6 +1,7 @@
 package inspector
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -115,11 +116,11 @@ func (i *UptimeDarwin) Execute() {
 //TODO: Windows equivalent of uptime
 
 // NewUptime : Initialize a new Uptime instance
-func NewUptime(driver *driver.Driver) Inspector {
+func NewUptime(driver *driver.Driver, _ ...string) (Inspector, error) {
 	var uptime Inspector
 	details := (*driver).GetDetails()
 	if !(details.IsDarwin || details.IsLinux) {
-		panic("Cannot use Uptime on drivers outside (linux, darwin)")
+		return nil, errors.New("Cannot use Uptime on drivers outside (linux, darwin)")
 	}
 	if details.IsLinux {
 		uptime = &UptimeLinux{
@@ -132,5 +133,5 @@ func NewUptime(driver *driver.Driver) Inspector {
 		}
 	}
 	uptime.SetDriver(driver)
-	return uptime
+	return uptime, nil
 }