Improvements to config and logging

Added log-level option to CLI

email-strategy.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	log "github.com/sirupsen/logrus"
 	"io"
 	"io/fs"
 	"mime/multipart"
@@ -154,10 +155,11 @@ func (e *Email) SetHtmlMessage(htmlMessage string) *Email {
 }
 
 func (e *Email) SetAttachments(attachments []string) *Email {
-	realAttachments := make([]string, len(attachments))
+	realAttachments := make([]string, 0, len(attachments))
 	for _, attachment := range attachments {
 		stat, err := os.Stat(attachment)
 		if err != nil {
+			_, _ = fmt.Fprintf(os.Stderr, "Error with attachment '%s'. Ignoring it. %s", attachment, err)
 			continue
 		}
 		if !stat.IsDir() {
@@ -166,8 +168,10 @@ func (e *Email) SetAttachments(attachments []string) *Email {
 		}
 
 		// add all files inside the directory
-		err = filepath.WalkDir(attachment, func(path string, d fs.DirEntry, err error) error {
+		log.Debugf("Attachment %s is a directory, walking the directory", attachment)
+		_ = filepath.WalkDir(attachment, func(path string, d fs.DirEntry, err error) error {
 			if err != nil {
+				_, _ = fmt.Fprintf(os.Stderr, "Error with attachment '%s'. Ignoring it. %s", path, err)
 				return nil // just ignore the error and continue, but don't add the file
 			}
 			if d.IsDir() {
@@ -177,16 +181,17 @@ func (e *Email) SetAttachments(attachments []string) *Email {
 			realAttachments = append(realAttachments, path)
 			return nil
 		})
-		if err != nil {
-			continue
-		}
 	}
-	e.attachments = attachments
+	e.attachments = realAttachments
 	return e
 }
 
 // CCEmails Returns only the emails in Email.cc
 func (e *Email) CCEmails() []string {
+	if e.cc == nil {
+		return nil
+	}
+
 	emails := make([]string, 0, len(e.cc))
 	for _, entity := range e.cc {
 		if entity.Email != "" {
@@ -198,6 +203,10 @@ func (e *Email) CCEmails() []string {
 
 // CCPGPKeyIds Returns the values of Email.cc
 func (e *Email) CCPGPKeyIds() []string {
+	if e.cc == nil {
+		return nil
+	}
+
 	keyIds := make([]string, 0, len(e.cc))
 	for _, entity := range e.cc {
 		if entity.PGPKeyId != "" {
@@ -232,15 +241,19 @@ func (e *Email) SendEmail() (interface{}, error) {
 		return nil, errors.New("strategy needs to be initiated")
 	}
 
+	log.Debugln("Creating email payload")
 	payload, err := e.CreatePayload()
 	if err != nil {
 		return nil, err
 	}
+	log.Debugln("Done creating email payload")
 
+	log.Debugln("Sending email payload")
 	res, err := e.strategy.SendEmail(payload, e.Sender().Email)
 	if err != nil {
 		return nil, err
 	}
+	log.Debugln("Done sending email payload")
 
 	return res, nil
 }
@@ -285,6 +298,16 @@ func createBasicHeaders(from, to, subject string) string {
 	)
 }
 
+func (e *Email) createCCHeader() string {
+	strBuilder := strings.Builder{}
+	if ccEmails := e.CCEmails(); ccEmails != nil && len(ccEmails) > 0 {
+		strBuilder.WriteString("Cc: ")
+		strBuilder.WriteString(strings.Join(ccEmails, ","))
+		strBuilder.WriteString("\r\n")
+	}
+	return strBuilder.String()
+}
+
 // CreateMessagePayload creates a multipart/alternative payload with the text plain and html message specified in e
 //
 // This is a pure function, i.e. e is not modified
@@ -344,11 +367,7 @@ func (e *Email) CreatePayload() ([]byte, error) {
 	payload.WriteString(createBasicHeaders(e.Sender().Email, e.Recipient().Email, e.subject))
 
 	// write CC headers
-	if e.cc != nil && len(e.cc) > 0 {
-		payload.WriteString("Cc: ")
-		payload.WriteString(strings.Join(e.CCEmails(), ","))
-		payload.WriteString("\r\n")
-	}
+	payload.WriteString(e.createCCHeader())
 	payload.WriteString("\r\nThis is a multi-part message in MIME format.\r\n")
 
 	// write message
@@ -416,11 +435,8 @@ func (e *Email) CreatePGPPayload() ([]byte, error) {
 	payload.WriteString(fmt.Sprintf("Content-Type: multipart/encrypted; protocol=\"application/pgp-encrypted\"; boundary=\"%s\"\r\n", mpWriter.Boundary()))
 	payload.WriteString(createBasicHeaders(e.Sender().Email, e.Recipient().Email, e.subject))
 
-	if e.cc != nil && len(e.cc) > 0 {
-		payload.WriteString("Cc: ")
-		payload.WriteString(strings.Join(e.CCEmails(), ","))
-		payload.WriteString("\r\n")
-	}
+	// write CC headers
+	payload.WriteString(e.createCCHeader())
 	payload.WriteString("\r\nThis is an OpenPGP/MIME encrypted message (RFC 4880 and 3156)\r\n")
 
 	// write PGP header for encrypted message and PGP version
@@ -531,6 +547,7 @@ func pgpEncrypt(data []byte, senderId string, recipientsIds ...string) ([]byte,
 		gpgArgs[i+1] = recipientsIds[(i-len(initialArgs))/2]
 	}
 
+	log.Debugln("Encrypting data. Executing gpg", gpgArgs)
 	encryptCmd := exec.Command("gpg", gpgArgs...)
 	stdin, err := encryptCmd.StdinPipe()
 	if err != nil {
@@ -557,7 +574,7 @@ func pgpEncrypt(data []byte, senderId string, recipientsIds ...string) ([]byte,
 	}
 
 	e, _ := io.ReadAll(stderr)
-	if err := encryptCmd.Wait(); err != nil { // if recipient's key doesn't exist, this will return an error
+	if err = encryptCmd.Wait(); err != nil { // if recipient's key doesn't exist, this will return an error
 		return nil, fmt.Errorf("error while encrypting PGP message, pgp stderr: \"%s\". %w", e, err)
 	}
 
@@ -578,6 +595,7 @@ func pgpSign(data []byte, senderId string, passphraseFile string) ([]byte, error
 		gpgArgs = append(gpgArgs, "--passphrase-file", passphraseFile)
 	}
 
+	log.Debugln("Signing data. Executing gpg", gpgArgs)
 	signCmd := exec.Command("gpg", gpgArgs...)
 	stdin, err := signCmd.StdinPipe()
 	if err != nil {

example.sh

@@ -4,4 +4,4 @@ if [ ! -f "login-monitor" ]; then
   go build
 fi
 
-./login-monitor --config example-config.json --gmail-oauth2-config client-secret.json --gmail-oauth2-token token.json
+./login-monitor --config config-example.json --gmail-oauth2-config client-secret.json --gmail-oauth2-token token.json

go.mod

@@ -5,9 +5,10 @@ go 1.16
 require (
 	cloud.google.com/go/compute v1.6.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/sirupsen/logrus v1.8.1 // indirect
 	golang.org/x/net v0.0.0-20220412020605-290c469a71a5 // indirect
 	golang.org/x/oauth2 v0.0.0-20220411215720-9780585627b5
-	golang.org/x/sys v0.0.0-20220412211240-33da011f77ad // indirect
+	golang.org/x/sys v0.0.0-20220422013727-9388b58f7150 // indirect
 	golang.org/x/xerrors v0.0.0-20220411194840-2f41105eb62f // indirect
 	google.golang.org/api v0.74.0
 	google.golang.org/genproto v0.0.0-20220414192740-2d67ff6cf2b4 // indirect

go.sum

@@ -71,6 +71,7 @@ github.com/cncf/xds/go v0.0.0-20210805033703-aa0b78936158/go.mod h1:eXthEFrGJvWH
 github.com/cncf/xds/go v0.0.0-20210922020428-25de7278fc84/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20211011173535-cb28da3451f1/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
@@ -176,8 +177,11 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
+github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE=
+github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
@@ -317,6 +321,7 @@ golang.org/x/sys v0.0.0-20190606165138-5da285871e9c/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190624142023-c5567b49c5d0/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191001151750-bb3f8db39f24/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191228213918-04cbcbbfeed8/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200113162924-86b910548bc1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -362,6 +367,8 @@ golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220328115105-d36c6a25d886/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220412211240-33da011f77ad h1:ntjMns5wyP/fN65tdBD4g8J5w8n015+iIIs9rtjXkY0=
 golang.org/x/sys v0.0.0-20220412211240-33da011f77ad/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220422013727-9388b58f7150 h1:xHms4gcpe1YE7A3yIllJXP16CMAGuqwO2lX1mTyyRRc=
+golang.org/x/sys v0.0.0-20220422013727-9388b58f7150/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

main.go

@@ -4,11 +4,12 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"log"
+	log "github.com/sirupsen/logrus"
 	"os"
+	"strings"
 )
 
-func configFlags(configPath, gmailOAuth2Config, gmailOAuth2Token *string) {
+func configFlags(configPath, gmailOAuth2Config, gmailOAuth2Token, logLevel *string) {
 	flag.StringVar(
 		configPath,
 		"config",
@@ -27,6 +28,13 @@ func configFlags(configPath, gmailOAuth2Config, gmailOAuth2Token *string) {
 		"token.json",
 		"Token file for the Gmail Oauth2 strategy",
 	)
+	flag.StringVar(
+		logLevel,
+		"log-level",
+		"error",
+		"Log level to use throughout the application. "+
+			"Valid values are: trace, debug, info, warn, error, fatal, panic",
+	)
 }
 
 // ensures permissions for the executable that started the process are set to 500 (r-x --- ---)
@@ -61,10 +69,30 @@ func main() {
 		fmt.Println("Error while checking permissions.", err)
 	}
 
-	var configFile, gmailOAuth2Config, gmailOAuth2Token string
-	configFlags(&configFile, &gmailOAuth2Config, &gmailOAuth2Token)
+	var configFile, gmailOAuth2Config, gmailOAuth2Token, logLevel string
+	configFlags(&configFile, &gmailOAuth2Config, &gmailOAuth2Token, &logLevel)
 	flag.Parse()
 
+	switch strings.TrimSpace(strings.ToLower(logLevel)) {
+	case "trace":
+		log.SetLevel(log.TraceLevel)
+	case "debug":
+		log.SetLevel(log.DebugLevel)
+	case "info":
+		log.SetLevel(log.InfoLevel)
+	case "warn":
+		log.SetLevel(log.WarnLevel)
+	case "error":
+		log.SetLevel(log.ErrorLevel)
+	case "fatal":
+		log.SetLevel(log.FatalLevel)
+	case "panic":
+		log.SetLevel(log.PanicLevel)
+	default:
+		fmt.Printf("%s is not recognized as a log level. Setting log level to error", logLevel)
+		log.SetLevel(log.ErrorLevel)
+	}
+
 	configReader, err := os.Open(configFile)
 	defer configReader.Close()
 	if err != nil {

message-example.html

@@ -3,5 +3,6 @@
         <p>New login on <b>%h</b> at <b>%t RFC822Z t%</b></p><br/>
         <p>Details are provided as attachments</p><br/>
         <p><i>Remember this information is confidential and please, RESPECT THE PRIVACY of other users</i></p>
+        <pre>%f go.mod f%</pre>
     </body>
 </html>

message-example.txt

@@ -1,3 +1,4 @@
 New login on %h at %t RFC822Z t%.
 Details are provided as attachments.
 Remember this information is confidential and please, RESPECT THE PRIVACY of other users
+%f go.mod f%