1 files changed, 184 insertions, 0 deletions
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
+}