merge develop

8 files changed, 599 insertions, 94 deletions

diff --git a/internal/config/args.go b/internal/config/args.go
new file mode 100644
index 0000000..3d7ac7d
--- /dev/null
+++ b/internal/config/args.go
@@ -0,0 +1,164 @@
+package config
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/mimecast/dtail/internal/lcontext"
+	"github.com/mimecast/dtail/internal/omode"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// Args is a helper struct to summarize common client arguments.
+type Args struct {
+	lcontext.LContext
+	Arguments          []string
+	ConfigFile         string
+	ConnectionsPerCPU  int
+	Discovery          string
+	LogDir             string
+	Logger             string
+	LogLevel           string
+	Mode               omode.Mode
+	NoColor            bool
+	PrivateKeyPathFile string
+	QueryStr           string
+	Quiet              bool
+	RegexInvert        bool
+	RegexStr           string
+	Serverless         bool
+	ServersStr         string
+	Spartan            bool
+	SSHAuthMethods     []gossh.AuthMethod
+	SSHBindAddress     string
+	SSHHostKeyCallback gossh.HostKeyCallback
+	SSHPort            int
+	Timeout            int
+	TrustAllHosts      bool
+	UserName           string
+	What               string
+}
+
+func (a *Args) String() string {
+	var sb strings.Builder
+
+	sb.WriteString("Args(")
+
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Arguments", a.Arguments))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "ConfigFile", a.ConfigFile))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "ConnectionsPerCPU", a.ConnectionsPerCPU))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Discovery", a.Discovery))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "LogDir", a.LogDir))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "LogLevel", a.LogLevel))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Logger", a.Logger))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Mode", a.Mode))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "NoColor", a.NoColor))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "PrivateKeyPathFile", a.PrivateKeyPathFile))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "QueryStr", a.QueryStr))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Quiet", a.Quiet))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "RegexInvert", a.RegexInvert))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "RegexStr", a.RegexStr))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "SSHAuthMethods", a.SSHAuthMethods))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "SSHBindAddress", a.SSHBindAddress))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "SSHHostKeyCallback", a.SSHHostKeyCallback))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "SSHPort", a.SSHPort))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Serverless", a.Serverless))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "ServersStr", a.ServersStr))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Spartan", a.Spartan))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "Timeout", a.Timeout))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "TrustAllHosts", a.TrustAllHosts))
+	sb.WriteString(fmt.Sprintf("%s:%v,", "UserName", a.UserName))
+	sb.WriteString(fmt.Sprintf("%s:%v", "What", a.What))
+	sb.WriteString(")")
+
+	return sb.String()
+}
+
+// SerializeOptions returns a string ready to be sent over the wire to the server.
+func (a *Args) SerializeOptions() string {
+	options := make(map[string]string)
+
+	if a.Quiet {
+		options["quiet"] = fmt.Sprintf("%v", a.Quiet)
+	}
+	if a.Spartan {
+		options["spartan"] = fmt.Sprintf("%v", a.Spartan)
+	}
+	if a.Serverless {
+		options["serverless"] = fmt.Sprintf("%v", a.Serverless)
+	}
+	if a.LContext.MaxCount != 0 {
+		options["max"] = fmt.Sprintf("%d", a.LContext.MaxCount)
+	}
+	if a.LContext.BeforeContext != 0 {
+		options["before"] = fmt.Sprintf("%d", a.LContext.BeforeContext)
+	}
+	if a.LContext.AfterContext != 0 {
+		options["after"] = fmt.Sprintf("%d", a.LContext.AfterContext)
+	}
+
+	var sb strings.Builder
+	var i int
+	for k, v := range options {
+		if i > 0 {
+			sb.WriteString(":")
+		}
+		sb.WriteString(k)
+		sb.WriteString("=")
+		sb.WriteString(v)
+		i++
+	}
+	return sb.String()
+}
+
+// DeserializeOptions deserializes the options, but into a map.
+func DeserializeOptions(opts []string) (map[string]string, lcontext.LContext, error) {
+	options := make(map[string]string, len(opts))
+	var ltx lcontext.LContext
+
+	for _, o := range opts {
+		kv := strings.SplitN(o, "=", 2)
+		if len(kv) != 2 {
+			return options, ltx, fmt.Errorf("Unable to parse options: %v", kv)
+		}
+		key := kv[0]
+		val := kv[1]
+
+		if strings.HasPrefix(val, "base64%") {
+			s := strings.SplitN(val, "%", 2)
+			decoded, err := base64.StdEncoding.DecodeString(s[1])
+			if err != nil {
+				return options, ltx, err
+			}
+			val = string(decoded)
+		}
+
+		switch key {
+		case "before":
+			iVal, err := strconv.Atoi(val)
+			if err != nil {
+				return options, ltx, err
+			}
+			ltx.BeforeContext = iVal
+		case "after":
+			iVal, err := strconv.Atoi(val)
+			if err != nil {
+				return options, ltx, err
+			}
+			ltx.AfterContext = iVal
+		case "max":
+			iVal, err := strconv.Atoi(val)
+			if err != nil {
+				return options, ltx, err
+			}
+			ltx.MaxCount = iVal
+		default:
+			options[key] = val
+		}
+	}
+
+	return options, ltx, nil
+}
diff --git a/internal/config/client.go b/internal/config/client.go
index 1515aae..86f97f0 100644
--- a/internal/config/client.go
+++ b/internal/config/client.go
@@ -1,11 +1,203 @@
 package config
 
+import "github.com/mimecast/dtail/internal/color"
+
+type remoteTermColors struct {
+	DelimiterAttr color.Attribute
+	DelimiterBg   color.BgColor
+	DelimiterFg   color.FgColor
+	RemoteAttr    color.Attribute
+	RemoteBg      color.BgColor
+	RemoteFg      color.FgColor
+	CountAttr     color.Attribute
+	CountBg       color.BgColor
+	CountFg       color.FgColor
+	HostnameAttr  color.Attribute
+	HostnameBg    color.BgColor
+	HostnameFg    color.FgColor
+	IDAttr        color.Attribute
+	IDBg          color.BgColor
+	IDFg          color.FgColor
+	StatsOkAttr   color.Attribute
+	StatsOkBg     color.BgColor
+	StatsOkFg     color.FgColor
+	StatsWarnAttr color.Attribute
+	StatsWarnBg   color.BgColor
+	StatsWarnFg   color.FgColor
+	TextAttr      color.Attribute
+	TextBg        color.BgColor
+	TextFg        color.FgColor
+}
+
+type clientTermColors struct {
+	DelimiterAttr color.Attribute
+	DelimiterBg   color.BgColor
+	DelimiterFg   color.FgColor
+	ClientAttr    color.Attribute
+	ClientBg      color.BgColor
+	ClientFg      color.FgColor
+	HostnameAttr  color.Attribute
+	HostnameBg    color.BgColor
+	HostnameFg    color.FgColor
+	TextAttr      color.Attribute
+	TextBg        color.BgColor
+	TextFg        color.FgColor
+}
+
+type serverTermColors struct {
+	DelimiterAttr color.Attribute
+	DelimiterBg   color.BgColor
+	DelimiterFg   color.FgColor
+	ServerAttr    color.Attribute
+	ServerBg      color.BgColor
+	ServerFg      color.FgColor
+	HostnameAttr  color.Attribute
+	HostnameBg    color.BgColor
+	HostnameFg    color.FgColor
+	TextAttr      color.Attribute
+	TextBg        color.BgColor
+	TextFg        color.FgColor
+}
+
+type commonTermColors struct {
+	SeverityErrorAttr color.Attribute
+	SeverityErrorBg   color.BgColor
+	SeverityErrorFg   color.FgColor
+	SeverityFatalAttr color.Attribute
+	SeverityFatalBg   color.BgColor
+	SeverityFatalFg   color.FgColor
+	SeverityWarnAttr  color.Attribute
+	SeverityWarnBg    color.BgColor
+	SeverityWarnFg    color.FgColor
+}
+
+type maprTableTermColors struct {
+	DataAttr            color.Attribute
+	DataBg              color.BgColor
+	DataFg              color.FgColor
+	DelimiterAttr       color.Attribute
+	DelimiterBg         color.BgColor
+	DelimiterFg         color.FgColor
+	HeaderAttr          color.Attribute
+	HeaderBg            color.BgColor
+	HeaderDelimiterAttr color.Attribute
+	HeaderDelimiterBg   color.BgColor
+	HeaderDelimiterFg   color.FgColor
+	HeaderFg            color.FgColor
+	HeaderGroupKeyAttr  color.Attribute
+	HeaderSortKeyAttr   color.Attribute
+	RawQueryAttr        color.Attribute
+	RawQueryBg          color.BgColor
+	RawQueryFg          color.FgColor
+}
+
+type termColors struct {
+	Remote    remoteTermColors
+	Client    clientTermColors
+	Server    serverTermColors
+	Common    commonTermColors
+	MaprTable maprTableTermColors
+}
+
 // ClientConfig represents a DTail client configuration (empty as of now as there
 // are no available config options yet, but that may changes in the future).
 type ClientConfig struct {
+	TermColorsEnable bool       `json:",omitempty"`
+	TermColors       termColors `json:",omitempty"`
+	// When unit testing in Jenkins you don't want to touch files in ~jenkins
+	// during integration tests really.
+	SSHDontAddHostsToKnownHostsFile bool `json:",omitempty"`
 }
 
 // Create a new default client configuration.
 func newDefaultClientConfig() *ClientConfig {
-	return &ClientConfig{}
+	return &ClientConfig{
+		TermColorsEnable: true,
+		TermColors: termColors{
+			Remote: remoteTermColors{
+				DelimiterAttr: color.AttrDim,
+				DelimiterBg:   color.BgBlue,
+				DelimiterFg:   color.FgCyan,
+				RemoteAttr:    color.AttrDim,
+				RemoteBg:      color.BgBlue,
+				RemoteFg:      color.FgWhite,
+				CountAttr:     color.AttrDim,
+				CountBg:       color.BgBlue,
+				CountFg:       color.FgWhite,
+				HostnameAttr:  color.AttrBold,
+				HostnameBg:    color.BgBlue,
+				HostnameFg:    color.FgWhite,
+				IDAttr:        color.AttrDim,
+				IDBg:          color.BgBlue,
+				IDFg:          color.FgWhite,
+				StatsOkAttr:   color.AttrNone,
+				StatsOkBg:     color.BgGreen,
+				StatsOkFg:     color.FgBlack,
+				StatsWarnAttr: color.AttrNone,
+				StatsWarnBg:   color.BgRed,
+				StatsWarnFg:   color.FgWhite,
+				TextAttr:      color.AttrNone,
+				TextBg:        color.BgBlack,
+				TextFg:        color.FgWhite,
+			},
+			Client: clientTermColors{
+				DelimiterAttr: color.AttrDim,
+				DelimiterBg:   color.BgYellow,
+				DelimiterFg:   color.FgBlack,
+				ClientAttr:    color.AttrDim,
+				ClientBg:      color.BgYellow,
+				ClientFg:      color.FgBlack,
+				HostnameAttr:  color.AttrDim,
+				HostnameBg:    color.BgYellow,
+				HostnameFg:    color.FgBlack,
+				TextAttr:      color.AttrNone,
+				TextBg:        color.BgBlack,
+				TextFg:        color.FgWhite,
+			},
+			Server: serverTermColors{
+				DelimiterAttr: color.AttrDim,
+				DelimiterBg:   color.BgCyan,
+				DelimiterFg:   color.FgBlack,
+				ServerAttr:    color.AttrDim,
+				ServerBg:      color.BgCyan,
+				ServerFg:      color.FgBlack,
+				HostnameAttr:  color.AttrBold,
+				HostnameBg:    color.BgCyan,
+				HostnameFg:    color.FgBlack,
+				TextAttr:      color.AttrNone,
+				TextBg:        color.BgBlack,
+				TextFg:        color.FgWhite,
+			},
+			Common: commonTermColors{
+				SeverityErrorAttr: color.AttrBold,
+				SeverityErrorBg:   color.BgRed,
+				SeverityErrorFg:   color.FgWhite,
+				SeverityFatalAttr: color.AttrBold,
+				SeverityFatalBg:   color.BgMagenta,
+				SeverityFatalFg:   color.FgWhite,
+				SeverityWarnAttr:  color.AttrBold,
+				SeverityWarnBg:    color.BgBlack,
+				SeverityWarnFg:    color.FgWhite,
+			},
+			MaprTable: maprTableTermColors{
+				DataAttr:            color.AttrNone,
+				DataBg:              color.BgBlue,
+				DataFg:              color.FgWhite,
+				DelimiterAttr:       color.AttrDim,
+				DelimiterBg:         color.BgBlue,
+				DelimiterFg:         color.FgWhite,
+				HeaderAttr:          color.AttrBold,
+				HeaderBg:            color.BgBlue,
+				HeaderFg:            color.FgWhite,
+				HeaderDelimiterAttr: color.AttrDim,
+				HeaderDelimiterBg:   color.BgBlue,
+				HeaderDelimiterFg:   color.FgWhite,
+				HeaderSortKeyAttr:   color.AttrUnderline,
+				HeaderGroupKeyAttr:  color.AttrReverse,
+				RawQueryAttr:        color.AttrDim,
+				RawQueryBg:          color.BgBlack,
+				RawQueryFg:          color.FgCyan,
+			},
+		},
+	}
 }
diff --git a/internal/config/common.go b/internal/config/common.go
index c3e203e..7a72cfe 100644
--- a/internal/config/common.go
+++ b/internal/config/common.go
@@ -6,31 +6,27 @@ type CommonConfig struct {
 	SSHPort int
 	// Enable experimental features (mainly for dev purposes)
 	ExperimentalFeaturesEnable bool `json:",omitempty"`
-	// Enable debug logging. Don't enable in production.
-	DebugEnable bool `json:",omitempty"`
-	// Enable trace logging. Don't enable in production.
-	TraceEnable bool `json:",omitempty"`
-	// The log strategy to use, one of
-	//   stdout: only log to stdout (useful when used with systemd)
-	//   daily: create a log file for every day
-	LogStrategy string
-	// The log directory
+	// LogDir defines the log directory.
 	LogDir string
+	// Logger defines the name of the logger implementation.
+	Logger string
+	// LogLevel defines how much is logged.
+	LogLevel string `json:",omitempty"`
+	// LogRotation strategy to be used.
+	LogRotation string
 	// The cache directory
 	CacheDir string
-	// The temp directory
-	TmpDir string `json:",omitempty"`
 }
 
 // Create a new default configuration.
 func newDefaultCommonConfig() *CommonConfig {
 	return &CommonConfig{
-		SSHPort:                    2222,
-		DebugEnable:                false,
-		TraceEnable:                false,
+		SSHPort:                    DefaultSSHPort,
 		ExperimentalFeaturesEnable: false,
 		LogDir:                     "log",
+		Logger:                     "stdout",
+		LogLevel:                   DefaultLogLevel,
+		LogRotation:                "daily",
 		CacheDir:                   "cache",
-		TmpDir:                     "/tmp",
 	}
 }
diff --git a/internal/config/config.go b/internal/config/config.go
index 276ddcf..ee23829 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -1,23 +1,30 @@
 package config
 
-import (
-	"encoding/json"
-	"io/ioutil"
-	"os"
+import "github.com/mimecast/dtail/internal/source"
+
+const (
+	// HealthUser is used for the health check
+	HealthUser string = "DTAIL-HEALTH"
+	// ScheduleUser is used for non-interactive scheduled mapreduce queries.
+	ScheduleUser string = "DTAIL-SCHEDULE"
+	// ContinuousUser is used for non-interactive continuous mapreduce queries.
+	ContinuousUser string = "DTAIL-CONTINUOUS"
+	// InterruptTimeoutS specifies the Ctrl+C log pause interval.
+	InterruptTimeoutS int = 3
+	// DefaultConnectionsPerCPU controls how many connections are established concurrently.
+	DefaultConnectionsPerCPU int = 10
+	// DefaultSSHPort is the default DServer port.
+	DefaultSSHPort int = 2222
+	// DefaultLogLevel specifies the default log level (obviously)
+	DefaultLogLevel string = "info"
+	// DefaultClientLogger specifies the default logger for the client commands.
+	DefaultClientLogger string = "fout"
+	// DefaultServerLogger specifies the default logger for dtail server.
+	DefaultServerLogger string = "file"
+	// DefaultHealthCheckLogger specifies the default logger used for health checks.
+	DefaultHealthCheckLogger string = "none"
 )
 
-// ControlUser is used for various DTail specific operations.
-const ControlUser string = "DTAIL-CONTROL"
-
-// ScheduleUser is used for non-interactive scheduled mapreduce queries.
-const ScheduleUser string = "DTAIL-SCHEDULE"
-
-// ContinuousUser is used for non-interactive continuous mapreduce queries.
-const ContinuousUser string = "DTAIL-CONTINUOUS"
-
-// InterruptTimeoutS is used to terminate DTail when Ctrl+C was pressed twice within a given interval.
-const InterruptTimeoutS int = 3
-
 // Client holds a DTail client configuration.
 var Client *ClientConfig
 
@@ -27,28 +34,22 @@ var Server *ServerConfig
 // Common holds common configs of both both, client and server.
 var Common *CommonConfig
 
-// Used to initialize the configuration.
-type configInitializer struct {
-	Common *CommonConfig
-	Server *ServerConfig
-	Client *ClientConfig
-}
-
-// Parse and read a given config file in JSON format.
-func (c *configInitializer) parseConfig(configFile string) {
-	fd, err := os.Open(configFile)
-	if err != nil {
-		panic(err)
+// Setup the DTail configuration.
+func Setup(sourceProcess source.Source, args *Args, additionalArgs []string) {
+	initializer := initializer{
+		Common: newDefaultCommonConfig(),
+		Server: newDefaultServerConfig(),
+		Client: newDefaultClientConfig(),
 	}
-	defer fd.Close()
-
-	cfgBytes, err := ioutil.ReadAll(fd)
-	if err != nil {
+	if err := initializer.parseConfig(args); err != nil {
 		panic(err)
 	}
-
-	err = json.Unmarshal([]byte(cfgBytes), c)
-	if err != nil {
+	if err := initializer.transformConfig(sourceProcess, args, additionalArgs); err != nil {
 		panic(err)
 	}
+
+	// Make config accessible globally
+	Server = initializer.Server
+	Client = initializer.Client
+	Common = initializer.Common
 }
diff --git a/internal/config/env.go b/internal/config/env.go
new file mode 100644
index 0000000..88b831d
--- /dev/null
+++ b/internal/config/env.go
@@ -0,0 +1,7 @@
+package config
+
+import "os"
+
+func Env(env string) bool {
+	return "yes" == os.Getenv(env)
+}
diff --git a/internal/config/initializer.go b/internal/config/initializer.go
new file mode 100644
index 0000000..4d6a73b
--- /dev/null
+++ b/internal/config/initializer.go
@@ -0,0 +1,184 @@
+package config
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/mimecast/dtail/internal/source"
+)
+
+// Used to initialize the configuration.
+type initializer struct {
+	Common *CommonConfig
+	Server *ServerConfig
+	Client *ClientConfig
+}
+
+type transformCb func(*initializer, *Args, []string) error
+
+func (in *initializer) parseConfig(args *Args) error {
+	if strings.ToUpper(args.ConfigFile) == "NONE" {
+		return nil
+	}
+
+	if args.ConfigFile != "" {
+		return in.parseSpecificConfig(args.ConfigFile)
+	}
+
+	if homeDir, err := os.UserHomeDir(); err != nil {
+		var paths []string
+		paths = append(paths, fmt.Sprintf("%s/.config/dtail/dtail.conf", homeDir))
+		paths = append(paths, fmt.Sprintf("%s/.dtail.conf", homeDir))
+		for _, configPath := range paths {
+			if _, err := os.Stat(configPath); !os.IsNotExist(err) {
+				in.parseSpecificConfig(configPath)
+			}
+		}
+	}
+
+	return nil
+}
+
+func (in *initializer) parseSpecificConfig(configFile string) error {
+	fd, err := os.Open(configFile)
+	if err != nil {
+		return fmt.Errorf("Unable to read config file: %v", err)
+	}
+	defer fd.Close()
+
+	cfgBytes, err := ioutil.ReadAll(fd)
+	if err != nil {
+		return fmt.Errorf("Unable to read config file %s: %v", configFile, err)
+	}
+
+	if err := json.Unmarshal([]byte(cfgBytes), in); err != nil {
+		return fmt.Errorf("Unable to parse config file %s: %v", configFile, err)
+	}
+
+	return nil
+}
+
+func (in *initializer) transformConfig(sourceProcess source.Source, args *Args,
+	additionalArgs []string) error {
+
+	in.readEnvironmentVars()
+
+	switch sourceProcess {
+	case source.Server:
+		return in.optimusPrime(transformServer, args, additionalArgs)
+	case source.Client:
+		return in.optimusPrime(transformClient, args, additionalArgs)
+	case source.HealthCheck:
+		return in.optimusPrime(transformHealthCheck, args, additionalArgs)
+	default:
+		return fmt.Errorf("Unable to transform config, unknown source '%s'",
+			sourceProcess)
+	}
+}
+
+// There are some special options which can be set by environment variable.
+func (in *initializer) readEnvironmentVars() {
+	if Env("DTAIL_SSH_DONT_ADD_HOSTS_TO_KNOWNHOSTS_FILE") ||
+		Env("DTAIL_JENKINS") {
+		in.Client.SSHDontAddHostsToKnownHostsFile = true
+	}
+}
+
+func (in *initializer) optimusPrime(sourceCb transformCb, args *Args,
+	additionalArgs []string) error {
+
+	// Copy args to config objects.
+	// NEXT: Maybe unify args and config structs?
+	if args.SSHPort != DefaultSSHPort {
+		in.Common.SSHPort = args.SSHPort
+	}
+	if args.LogLevel != DefaultLogLevel {
+		in.Common.LogLevel = args.LogLevel
+	}
+	if args.NoColor {
+		in.Client.TermColorsEnable = false
+	}
+	if args.LogDir != "" {
+		in.Common.LogDir = args.LogDir
+	}
+	if args.Logger != "" {
+		in.Common.Logger = args.Logger
+	}
+	if args.ConnectionsPerCPU == 0 {
+		args.ConnectionsPerCPU = DefaultConnectionsPerCPU
+	}
+
+	// Setup log directory.
+	if strings.Contains(in.Common.LogDir, "~/") {
+		homeDir, err := os.UserHomeDir()
+		if err != nil {
+			panic(err)
+		}
+		in.Common.LogDir = strings.ReplaceAll(in.Common.LogDir, "~/",
+			fmt.Sprintf("%s/", homeDir))
+	}
+
+	// Source type specific transormations.
+	sourceCb(in, args, additionalArgs)
+
+	// Spartan mode.
+	if args.Spartan {
+		args.Quiet = true
+		args.NoColor = true
+		in.Client.TermColorsEnable = false
+		if args.LogLevel == "" {
+			args.LogLevel = "ERROR"
+			in.Common.LogLevel = "ERROR"
+		}
+	}
+	// Interpret additional args as file list or as query.
+	if args.What == "" {
+		var files []string
+		for _, arg := range flag.Args() {
+			if args.QueryStr == "" && strings.Contains(strings.ToLower(arg), "select ") {
+				args.QueryStr = arg
+				continue
+			}
+			files = append(files, arg)
+		}
+		args.What = strings.Join(files, ",")
+	}
+
+	return nil
+}
+
+func transformClient(in *initializer, args *Args, additionalArgs []string) error {
+	// Serverless mode.
+	if args.Discovery == "" && (args.ServersStr == "" ||
+		strings.ToLower(args.ServersStr) == "serverless") {
+		// We are not connecting to any servers.
+		args.Serverless = true
+		if args.LogLevel == DefaultLogLevel {
+			in.Common.LogLevel = "warn"
+		}
+	}
+	return nil
+}
+
+func transformServer(in *initializer, args *Args, additionalArgs []string) error {
+	if args.SSHBindAddress != "" {
+		in.Server.SSHBindAddress = args.SSHBindAddress
+	}
+	return nil
+}
+
+func transformHealthCheck(in *initializer, args *Args, additionalArgs []string) error {
+	// Serverless mode.
+	if args.Discovery == "" && (args.ServersStr == "" ||
+		strings.ToLower(args.ServersStr) == "serverless") {
+		// We are not connecting to any servers.
+		args.Serverless = true
+		in.Common.LogLevel = "warn"
+	}
+	args.TrustAllHosts = true
+	return nil
+}
diff --git a/internal/config/read.go b/internal/config/read.go
deleted file mode 100644
index a4e605b..0000000
--- a/internal/config/read.go
+++ /dev/null
@@ -1,37 +0,0 @@
-package config
-
-import (
-	"os"
-)
-
-// Read the DTail configuration.
-func Read(configFile string, sshPort int) {
-	initializer := configInitializer{
-		Common: newDefaultCommonConfig(),
-		Server: newDefaultServerConfig(),
-		Client: newDefaultClientConfig(),
-	}
-
-	if configFile == "" {
-		configFile = "./cfg/dtail.json"
-	}
-
-	if _, err := os.Stat(configFile); !os.IsNotExist(err) {
-		initializer.parseConfig(configFile)
-	}
-
-	// Assign pointers to global variables, so that we can access the
-	// configuration from any place of the program.
-	Common = initializer.Common
-	Server = initializer.Server
-	Client = initializer.Client
-
-	if Server.MapreduceLogFormat == "" {
-		Server.MapreduceLogFormat = "default"
-	}
-
-	// If non-standard port specified, overwrite config
-	if sshPort != 2222 {
-		Common.SSHPort = sshPort
-	}
-}
diff --git a/internal/config/server.go b/internal/config/server.go
index dc0d587..254ea0c 100644
--- a/internal/config/server.go
+++ b/internal/config/server.go
@@ -4,8 +4,8 @@ import (
 	"errors"
 )
 
-// Permissions map. Each SSH user has a list of permissions which
-// log files it is allowed to follow and which ones not.
+// Permissions map. Each SSH user has a list of permissions which log files it
+// is allowed to follow and which ones not.
 type Permissions struct {
 	// The default user permissions.
 	Default []string
@@ -47,7 +47,7 @@ type ServerConfig struct {
 	MaxConcurrentCats int
 	// The max amount of concurrent tails per server.
 	MaxConcurrentTails int
-	// The user permissions.
+	// The user permissions. TODO: Add to JSON schema
 	Permissions Permissions `json:",omitempty"`
 	// The mapr log format
 	MapreduceLogFormat string `json:",omitempty"`
@@ -68,7 +68,6 @@ var ServerRelaxedAuthEnable bool
 func newDefaultServerConfig() *ServerConfig {
 	defaultPermissions := []string{"^/.*"}
 	defaultBindAddress := "0.0.0.0"
-
 	return &ServerConfig{
 		SSHBindAddress:     defaultBindAddress,
 		MaxConnections:     10,
@@ -76,6 +75,7 @@ func newDefaultServerConfig() *ServerConfig {
 		MaxConcurrentTails: 50,
 		HostKeyFile:        "./cache/ssh_host_key",
 		HostKeyBits:        4096,
+		MapreduceLogFormat: "default",
 		Permissions: Permissions{
 			Default: defaultPermissions,
 		},
@@ -88,10 +88,8 @@ func ServerUserPermissions(userName string) (permissions []string, err error) {
 	if p, ok := Server.Permissions.Users[userName]; ok {
 		permissions = p
 	}
-
 	if len(permissions) == 0 {
 		err = errors.New("Empty set of permission, user won't be able to open any files")
 	}
-
 	return
 }