Fix/followup fix kinesis compression (open-telemetry#32860)

**Description:** 
Follow up fix on kinesis exporter compression. The streams were not
closed properly so the compressed data was not generating compression
footers


**Testing:** 
* tested compressed and uncompressed data locally
* modified compressor test to validate uncompressed data by content and
not just size

.chloggen/fix_followup-fix-kinesis-compression.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: awskinesisexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: fixed compressed data not generating the compression footers
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [32860]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

exporter/awskinesisexporter/internal/compress/compresser.go

@@ -31,7 +31,6 @@ func NewCompressor(format string) (Compressor, error) {
 func flateCompressor(in []byte) ([]byte, error) {
 	var buf bytes.Buffer
 	w, _ := flate.NewWriter(&buf, flate.BestSpeed)
-	defer w.Close()
 
 	_, err := w.Write(in)
 
@@ -44,13 +43,17 @@ func flateCompressor(in []byte) ([]byte, error) {
 		return nil, err
 	}
 
+	err = w.Close()
+	if err != nil {
+		return nil, err
+	}
+
 	return buf.Bytes(), nil
 }
 
 func gzipCompressor(in []byte) ([]byte, error) {
 	var buf bytes.Buffer
 	w, _ := gzip.NewWriterLevel(&buf, gzip.BestSpeed)
-	defer w.Close()
 
 	_, err := w.Write(in)
 
@@ -59,6 +62,12 @@ func gzipCompressor(in []byte) ([]byte, error) {
 	}
 
 	err = w.Flush()
+	if err != nil {
+
+		return nil, err
+	}
+
+	err = w.Close()
 	if err != nil {
 		return nil, err
 	}
@@ -69,7 +78,6 @@ func gzipCompressor(in []byte) ([]byte, error) {
 func zlibCompressor(in []byte) ([]byte, error) {
 	var buf bytes.Buffer
 	w, _ := zlib.NewWriterLevel(&buf, zlib.BestSpeed)
-	defer w.Close()
 
 	_, err := w.Write(in)
 
@@ -82,6 +90,11 @@ func zlibCompressor(in []byte) ([]byte, error) {
 		return nil, err
 	}
 
+	err = w.Close()
+	if err != nil {
+		return nil, err
+	}
+
 	return buf.Bytes(), nil
 }
 

exporter/awskinesisexporter/internal/compress/compresser_test.go

@@ -4,7 +4,12 @@
 package compress_test
 
 import (
+	"bytes"
+	"compress/flate"
+	"compress/gzip"
+	"compress/zlib"
 	"fmt"
+	"io"
 	"math/rand"
 	"sync"
 	"testing"
@@ -29,7 +34,8 @@ func TestCompressorFormats(t *testing.T) {
 		{format: "flate"},
 	}
 
-	const data = "You know nothing Jon Snow"
+	data := createRandomString(1024)
+
 	for _, tc := range testCases {
 		t.Run(fmt.Sprintf("format_%s", tc.format), func(t *testing.T) {
 			c, err := compress.NewCompressor(tc.format)
@@ -39,12 +45,44 @@ func TestCompressorFormats(t *testing.T) {
 			out, err := c([]byte(data))
 			assert.NoError(t, err, "Must not error when processing data")
 			assert.NotNil(t, out, "Must have a valid record")
+
+			// now data gets decompressed and the original string gets compared with the decompressed one
+			var dc []byte
+			var err2 error
+
+			switch tc.format {
+			case "gzip":
+				dc, err2 = decompressGzip(out)
+			case "zlib":
+				dc, err2 = decompressZlib(out)
+			case "flate":
+				dc, err2 = decompressFlate(out)
+			case "noop", "none":
+				dc = out
+			default:
+				dc = out
+			}
+
+			assert.NoError(t, err2)
+			assert.Equal(t, data, string(dc))
 		})
 	}
 	_, err := compress.NewCompressor("invalid-format")
 	assert.Error(t, err, "Must error when an invalid compression format is given")
 }
 
+func createRandomString(length int) string {
+	// some characters for the random generation
+	const letterBytes = " ,.;:*-+/[]{}<>abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+	b := make([]byte, length)
+	for i := range b {
+		b[i] = letterBytes[rand.Intn(len(letterBytes))]
+	}
+
+	return string(b)
+}
+
 func BenchmarkNoopCompressor_1000Bytes(b *testing.B) {
 	benchmarkCompressor(b, "none", 1000)
 }
@@ -178,3 +216,48 @@ func concurrentCompressFunc(t *testing.T) {
 		t.Errorf("Error encountered on concurrent compression: %v", err)
 	}
 }
+
+func decompressGzip(input []byte) ([]byte, error) {
+	r, err := gzip.NewReader(bytes.NewReader(input))
+	if err != nil {
+		return nil, err
+	}
+
+	defer r.Close()
+
+	decompressedData, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	return decompressedData, nil
+}
+
+func decompressZlib(input []byte) ([]byte, error) {
+	r, err := zlib.NewReader(bytes.NewReader(input))
+	if err != nil {
+		return nil, err
+	}
+
+	defer r.Close()
+
+	decompressedData, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	return decompressedData, nil
+}
+
+func decompressFlate(input []byte) ([]byte, error) {
+
+	r := flate.NewReader(bytes.NewReader(input))
+	defer r.Close()
+
+	decompressedData, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	return decompressedData, nil
+}