feat: new helpers and masking/encrypting attributes

New helper functions were added to make call-site less likely to need
to pull `go.opentelemetry.io/otel/attribute` as a dependency.
Additionally `Encrypted` and `Masked` were added to add a possibility of
logging sensitive data in a more secure manner.

example/main.go

@@ -8,6 +8,7 @@ import (
 	"os/signal"
 	"time"
 
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
 	"git.ma-al.com/maal-libraries/observer/pkg/attr/layer_attr"
 	"git.ma-al.com/maal-libraries/observer/pkg/event"
 	"git.ma-al.com/maal-libraries/observer/pkg/exporters"
@@ -111,6 +112,11 @@ func Serv(ctx context.Context) *fiber.Error {
 		return fiber.NewError(500, "xd")
 	}
 
+	span.SetAttributes(
+		attr.Masked("some_masked_value", "some_masked_value"),
+		attr.Encrypted("some_encrypted_value", "some_encrypted_value"),
+	)
+
 	return fiber.NewError(500, "x")
 }
 

go.mod

@@ -4,12 +4,13 @@ go 1.21
 
 require (
 	github.com/gofiber/fiber/v2 v2.52.4
-	github.com/psmarcin/fiber-opentelemetry v1.2.0
+	github.com/gofrs/uuid v4.4.0+incompatible
 	go.opentelemetry.io/otel v1.26.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.26.0
 	go.opentelemetry.io/otel/sdk v1.26.0
 	go.opentelemetry.io/otel/trace v1.26.0
 	gopkg.in/Graylog2/go-gelf.v2 v2.0.0-20191017102106-1550ee647df0
+	gorm.io/gorm v1.25.11
 )
 
 require (
@@ -39,5 +40,4 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240401170217-c3f982113cda // indirect
 	google.golang.org/grpc v1.63.2 // indirect
 	google.golang.org/protobuf v1.33.0 // indirect
-	gorm.io/gorm v1.25.11 // indirect
 )

go.sum

@@ -1,21 +1,18 @@
-github.com/andybalholm/brotli v1.0.4/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
 github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1U3M=
 github.com/andybalholm/brotli v1.1.0/go.mod h1:sms7XGricyQI9K10gOSf56VKKWS4oLer58Q+mhRPtnY=
 github.com/cenkalti/backoff/v4 v4.3.0 h1:MyRJ/UdXutAwSAT+s3wNd7MfTIcy71VQueUuFK343L8=
 github.com/cenkalti/backoff/v4 v4.3.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
-github.com/go-logr/logr v1.2.3/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
 github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
-github.com/gofiber/fiber/v2 v2.31.0/go.mod h1:1Ega6O199a3Y7yDGuM9FyXDPYQfv+7/y48wl6WCwUF4=
 github.com/gofiber/fiber/v2 v2.52.4 h1:P+T+4iK7VaqUsq2PALYEfBBo6bJZ4q3FP8cZ84EggTM=
 github.com/gofiber/fiber/v2 v2.52.4/go.mod h1:KEOE+cXMhXG0zHc9d8+E38hoX+ZN7bhOtgeF2oT6jrQ=
-github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
+github.com/gofrs/uuid v4.4.0+incompatible h1:3qXRTX8/NbyulANqlc0lchS1gqAVxRgsuW1YrTJupqA=
+github.com/gofrs/uuid v4.4.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
@@ -26,7 +23,6 @@ github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD
 github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
 github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
 github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
-github.com/klauspost/compress v1.15.0/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
 github.com/klauspost/compress v1.17.8 h1:YcnTYrq7MikUT7k0Yb5eceMmALQPYBW/Xltxn0NAMnU=
 github.com/klauspost/compress v1.17.8/go.mod h1:Di0epgTjJY877eYKx5yC51cX2A2Vl2ibi7bDH9ttBbw=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
@@ -38,23 +34,17 @@ github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZ
 github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/psmarcin/fiber-opentelemetry v1.2.0 h1:3e3bz1jmwKMnoM5RVU4YzMXBq8tZQzzMDyM7DW1mTz8=
-github.com/psmarcin/fiber-opentelemetry v1.2.0/go.mod h1:qcEVkzlD0GrjtCS+hd5/0QhbTOy12KNyaqmp4yfXi1c=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasthttp v1.34.0/go.mod h1:epZA5N+7pY6ZaEKRmstzOuYJx9HI8DI1oaCGZpdH4h0=
 github.com/valyala/fasthttp v1.52.0 h1:wqBQpxH71XW0e2g+Og4dzQM8pk34aFYlA1Ga8db7gU0=
 github.com/valyala/fasthttp v1.52.0/go.mod h1:hf5C4QnVMkNXMspnsUlfM3WitlgYflyhHYoKol/szxQ=
 github.com/valyala/tcplisten v1.0.0 h1:rBHj/Xf+E1tRGZyWIWwJDiRY0zc1Js+CV5DqwacVSA8=
 github.com/valyala/tcplisten v1.0.0/go.mod h1:T0xQ8SeCZGxckz9qRXTfG43PvQ/mcWh7FwZEA7Ioqkc=
-go.opentelemetry.io/otel v1.6.3/go.mod h1:7BgNga5fNlF/iZjG06hM3yofffp0ofKCDwSXx1GC4dI=
 go.opentelemetry.io/otel v1.26.0 h1:LQwgL5s/1W7YiiRwxf03QGnWLb2HW4pLiAhaA5cZXBs=
 go.opentelemetry.io/otel v1.26.0/go.mod h1:UmLkJHUAidDval2EICqBMbnAd0/m2vmpf/dAM+fvFs4=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.26.0 h1:1u/AyyOqAWzy+SkPxDpahCNZParHV8Vid1RnI2clyDE=
@@ -65,33 +55,18 @@ go.opentelemetry.io/otel/metric v1.26.0 h1:7S39CLuY5Jgg9CrnA9HHiEjGMF/X2VHvoXGgS
 go.opentelemetry.io/otel/metric v1.26.0/go.mod h1:SY+rHOI4cEawI9a7N1A4nIg/nTQXe1ccCNWYOJUrpX4=
 go.opentelemetry.io/otel/sdk v1.26.0 h1:Y7bumHf5tAiDlRYFmGqetNcLaVUZmh4iYfmGxtmz7F8=
 go.opentelemetry.io/otel/sdk v1.26.0/go.mod h1:0p8MXpqLeJ0pzcszQQN4F0S5FVjBLgypeGSngLsmirs=
-go.opentelemetry.io/otel/trace v1.6.3/go.mod h1:GNJQusJlUgZl9/TQBPKU/Y/ty+0iVB5fjhKeJGZPGFs=
 go.opentelemetry.io/otel/trace v1.26.0 h1:1ieeAUb4y0TE26jUFrCIXKpTuVK7uJGN9/Z/2LP5sQA=
 go.opentelemetry.io/otel/trace v1.26.0/go.mod h1:4iDxvGDQuUkHve82hJJ8UqrwswHYsZuWCBllGV2U2y0=
 go.opentelemetry.io/proto/otlp v1.2.0 h1:pVeZGk7nXDC9O2hncA6nHldxEjm6LByfA2aN8IOkz94=
 go.opentelemetry.io/proto/otlp v1.2.0/go.mod h1:gGpR8txAl5M03pDhMC79G6SdqNV26naRm/KDsgaHD8A=
-golang.org/x/crypto v0.0.0-20220214200702-86341886e292/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
-golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.0.0-20220225172249-27dd8689420f/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
 golang.org/x/net v0.23.0 h1:7EYJ93RZ9vYSZAIb2x3lnuvqO5zneoD6IvWjuhfxjTs=
 golang.org/x/net v0.23.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
 golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-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 v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/genproto v0.0.0-20240227224415-6ceb2ff114de h1:F6qOa9AZTYJXOUEr4jDysRDLrm4PHePlge4v4TGAlxY=
 google.golang.org/genproto v0.0.0-20240227224415-6ceb2ff114de/go.mod h1:VUhTRKeHn9wwcdrk73nvdC9gF178Tzhmt/qyaFcPLSo=
 google.golang.org/genproto/googleapis/api v0.0.0-20240227224415-6ceb2ff114de h1:jFNzHPIeuzhdRwVhbZdiym9q0ory/xY3sA+v2wPg8I0=
@@ -104,8 +79,6 @@ google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGm
 google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/Graylog2/go-gelf.v2 v2.0.0-20191017102106-1550ee647df0 h1:Xg23ydYYJLmb9AK3XdcEpplHZd1MpN3X2ZeeMoBClmY=
 gopkg.in/Graylog2/go-gelf.v2 v2.0.0-20191017102106-1550ee647df0/go.mod h1:CeDeqW4tj9FrgZXF/dQCWZrBdcZWWBenhJtxLH4On2g=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gorm.io/gorm v1.25.11 h1:/Wfyg1B/je1hnDx3sMkX+gAlxrlZpn6X0BXRlwXlvHg=

pkg/attr/attr.go

@@ -1,18 +1,27 @@
 package attr
 
 import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/hex"
 	"encoding/json"
+	"errors"
+	"io"
 	"os"
 	"runtime"
 	"runtime/debug"
 	"time"
 
 	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"github.com/gofrs/uuid"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/semconv/v1.25.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.25.0"
 	"go.opentelemetry.io/otel/trace"
 )
 
+type KV = attribute.KeyValue
 type KeyValue = attribute.KeyValue
 type Key = attribute.Key
 type Value = attribute.Value
@@ -72,11 +81,192 @@ const (
 	LayerUtil                                         = "util"
 )
 
+type secretKey struct {
+	Key    []byte
+	Cipher cipher.Block
+	Nonce  []byte
+}
+
+// Interprets a string as AES secret key (32 bytes) first decoding it with base64
+// It can be used to set the variable `EncryptSecretKey` which is responsible
+// for encrypting the `Encrypted` attributes.
+func NewSecretKey(key string) (secretKey, error) {
+	keyBytes, err := base64.RawStdEncoding.DecodeString(key)
+	if err != nil {
+		return secretKey{}, err
+	}
+	if len(keyBytes) != 32 {
+		return secretKey{}, errors.New("wrong length of encryption key, should be 32 bits")
+	}
+	cipher, err := aes.NewCipher(keyBytes)
+	if err != nil {
+		return secretKey{}, err
+	}
+	nonce := make([]byte, 12)
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return secretKey{}, err
+	}
+	return secretKey{
+		Key:    keyBytes,
+		Cipher: cipher,
+		Nonce:  nonce,
+	}, nil
+}
+
+// **Unless set, it will default to a random key that cannot be later retrievied!**
+//
+// The variable is used to encrypt values provided to the `Encrypted` attribute.
+var EncryptSecretKey secretKey = func() secretKey {
+	key := make([]byte, 32)
+	rand.Read(key)
+	cipher, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+	nonce := make([]byte, 12)
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		panic(err)
+	}
+	return secretKey{
+		Key:    key,
+		Cipher: cipher,
+		Nonce:  nonce,
+	}
+}()
+
 // Build an attribute with a value formatted as json
 func JsonAttr(key string, jsonEl map[string]interface{}) attribute.KeyValue {
 	jsonStr, _ := json.Marshal(jsonEl)
 	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(jsonStr))}
+}
 
+// Create an arbitrary attribute with value marshalled to json.
+// In case of marshalling error, it is returned in place of value.
+func Json[M json.Marshaler](key string, val M) attribute.KeyValue {
+	data, err := json.Marshal(val)
+	if err != nil {
+		return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(err.Error())}
+	} else {
+		return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(data))}
+	}
+}
+
+// Create an arbitrary attribute with a `string` value.
+func String(key string, val string) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(val)}
+}
+
+// Create an arbitrary attribute with a `[]string` value.
+func StringSlice(key string, val []string) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringSliceValue(val)}
+}
+
+// Create an arbitrary attribute with an `int` value.
+func Int(key string, val int) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.IntValue(val)}
+}
+
+// Create an arbitrary attribute with an `int64` value.
+func Int64(key string, val int64) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.Int64Value(val)}
+}
+
+// Cast value to an `int` to create a new attribute.
+func Uint(key string, val uint) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.IntValue(int(val))}
+}
+
+// Cast value to an `int` to create a new attribute.
+func Uint8(key string, val uint8) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.IntValue(int(val))}
+}
+
+// Create an arbitrary attribute using an `uuid.UUID` from `github.com/gofrs/uuid` as value.
+func Uuid(key string, val uuid.UUID) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(val.String())}
+}
+
+// Create an arbitrary attribute using standard library's `time.Time` as value. It will be formatted using RFC3339.
+func Time(key string, val time.Time) attribute.KeyValue {
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(val.Format(time.RFC3339))}
+}
+
+// Create an arbitrary attribute with bytes encoded to base64 (RFC 4648) as value.
+func BytesB64(key string, val []byte) attribute.KeyValue {
+	res := base64.StdEncoding.EncodeToString(val)
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(res)}
+}
+
+// Create an arbitrary attribute with bytes encoded to hexadecimal format as value.
+func BytesHex(key string, val []byte) attribute.KeyValue {
+	res := hex.EncodeToString(val)
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(res)}
+}
+
+// Create an arbitrary attribute with value encrypted using `secretKey` which should be set on
+// global variable `EncryptSecretKey` using `NewSecretKey`. The result will be encoded using
+// base64.
+//
+// This approach is an alternative to logs tokenization. It is using AES symmetric encryption
+// that is suspectible to brute force attacks. It is a computionally expensive attribute to
+// generate.
+//
+// In most cases, for very sensitive data it would be a better approach to use masking instead.
+// Encrypting the fields of the logs/traces can provide an extra protection while they are being
+// transported to a log collector and when the collector does not encrypt logs at rest (but most
+// should implement this feature). This will mostly protect the logs from developers working
+// with them provided that they do not have access to the key. The key should be set from an
+// environment variable defined on application deployment. Alternatively it could be set from
+// a secure vault, a software for storing private keys.
+func Encrypted(key string, val string) attribute.KeyValue {
+	aesGcm, err := cipher.NewGCM(EncryptSecretKey.Cipher)
+	if err != nil {
+		return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(err.Error())}
+	}
+	resBytes := aesGcm.Seal(nil, EncryptSecretKey.Nonce, []byte(val), nil)
+	res := base64.StdEncoding.EncodeToString(resBytes)
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(res)}
+}
+
+// Creates an arbitrary attribute with masked value. It will leave only last 4 (or less) characters
+// unmasked by 'X' characters.
+//
+// It is not a good idea to use it for logging passwords as it preserves the lenght of the input.
+//
+// Masking is a good idea for very sensitive data like official identity numbers, or addresses.
+// Storing such data in logs is usually too much of a risk even when it is encrypted.
+// However, for the purpose of debugging it might be convenient to be able to distinguish one record
+// from another.
+func Masked(key string, val string) attribute.KeyValue {
+	lenght := len(val)
+	var unmasked int
+
+	if lenght <= 4 {
+		unmasked = 1
+	} else {
+		if lenght <= 8 {
+			unmasked = 2
+		} else {
+			if lenght <= 12 {
+				unmasked = 3
+			} else {
+				unmasked = 4
+			}
+		}
+	}
+
+	masked := lenght - unmasked
+	resBytes := make([]byte, lenght)
+	i := 0
+
+	for ; i < masked; i++ {
+		resBytes[i] = byte('X')
+	}
+	for ; i < lenght; i++ {
+		resBytes[i] = byte(val[i])
+	}
+
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(resBytes))}
 }
 
 // An attribute informing about the severity or importance of an event using our own standard of log levels that