Merging upstream version 1.46.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 707 insertions, 0 deletions

diff --git a/src/streaming/compression.c b/src/streaming/compression.c
new file mode 100644
index 000000000..a94c8a0a6
--- /dev/null
+++ b/src/streaming/compression.c
@@ -0,0 +1,707 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "compression.h"
+
+#include "compression_gzip.h"
+
+#ifdef ENABLE_LZ4
+#include "compression_lz4.h"
+#endif
+
+#ifdef ENABLE_ZSTD
+#include "compression_zstd.h"
+#endif
+
+#ifdef ENABLE_BROTLI
+#include "compression_brotli.h"
+#endif
+
+int rrdpush_compression_levels[COMPRESSION_ALGORITHM_MAX] = {
+        [COMPRESSION_ALGORITHM_NONE]    = 0,
+        [COMPRESSION_ALGORITHM_ZSTD]    = 3,    // 1 (faster)  - 22 (smaller)
+        [COMPRESSION_ALGORITHM_LZ4]     = 1,    // 1 (smaller) -  9 (faster)
+        [COMPRESSION_ALGORITHM_BROTLI]  = 3,    // 0 (faster)  - 11 (smaller)
+        [COMPRESSION_ALGORITHM_GZIP]    = 1,    // 1 (faster)  -  9 (smaller)
+};
+
+void rrdpush_parse_compression_order(struct receiver_state *rpt, const char *order) {
+    // empty all slots
+    for(size_t i = 0; i < COMPRESSION_ALGORITHM_MAX ;i++)
+        rpt->config.compression_priorities[i] = STREAM_CAP_NONE;
+
+    char *s = strdupz(order);
+
+    char *words[COMPRESSION_ALGORITHM_MAX + 100] = { NULL };
+    size_t num_words = quoted_strings_splitter_pluginsd(s, words, COMPRESSION_ALGORITHM_MAX + 100);
+    size_t slot = 0;
+    STREAM_CAPABILITIES added = STREAM_CAP_NONE;
+    for(size_t i = 0; i < num_words && slot < COMPRESSION_ALGORITHM_MAX ;i++) {
+        if((STREAM_CAP_ZSTD_AVAILABLE) && strcasecmp(words[i], "zstd") == 0 && !(added & STREAM_CAP_ZSTD)) {
+            rpt->config.compression_priorities[slot++] = STREAM_CAP_ZSTD;
+            added |= STREAM_CAP_ZSTD;
+        }
+        else if((STREAM_CAP_LZ4_AVAILABLE) && strcasecmp(words[i], "lz4") == 0 && !(added & STREAM_CAP_LZ4)) {
+            rpt->config.compression_priorities[slot++] = STREAM_CAP_LZ4;
+            added |= STREAM_CAP_LZ4;
+        }
+        else if((STREAM_CAP_BROTLI_AVAILABLE) && strcasecmp(words[i], "brotli") == 0 && !(added & STREAM_CAP_BROTLI)) {
+            rpt->config.compression_priorities[slot++] = STREAM_CAP_BROTLI;
+            added |= STREAM_CAP_BROTLI;
+        }
+        else if(strcasecmp(words[i], "gzip") == 0 && !(added & STREAM_CAP_GZIP)) {
+            rpt->config.compression_priorities[slot++] = STREAM_CAP_GZIP;
+            added |= STREAM_CAP_GZIP;
+        }
+    }
+
+    freez(s);
+
+    // make sure all participate
+    if((STREAM_CAP_ZSTD_AVAILABLE) && slot < COMPRESSION_ALGORITHM_MAX && !(added & STREAM_CAP_ZSTD))
+        rpt->config.compression_priorities[slot++] = STREAM_CAP_ZSTD;
+    if((STREAM_CAP_LZ4_AVAILABLE) && slot < COMPRESSION_ALGORITHM_MAX && !(added & STREAM_CAP_LZ4))
+        rpt->config.compression_priorities[slot++] = STREAM_CAP_LZ4;
+    if((STREAM_CAP_BROTLI_AVAILABLE) && slot < COMPRESSION_ALGORITHM_MAX && !(added & STREAM_CAP_BROTLI))
+        rpt->config.compression_priorities[slot++] = STREAM_CAP_BROTLI;
+    if(slot < COMPRESSION_ALGORITHM_MAX && !(added & STREAM_CAP_GZIP))
+        rpt->config.compression_priorities[slot++] = STREAM_CAP_GZIP;
+}
+
+void rrdpush_select_receiver_compression_algorithm(struct receiver_state *rpt) {
+    if (!rpt->config.rrdpush_compression)
+        rpt->capabilities &= ~STREAM_CAP_COMPRESSIONS_AVAILABLE;
+
+    // select the right compression before sending our capabilities to the child
+    if(stream_has_more_than_one_capability_of(rpt->capabilities, STREAM_CAP_COMPRESSIONS_AVAILABLE)) {
+        STREAM_CAPABILITIES compressions = rpt->capabilities & STREAM_CAP_COMPRESSIONS_AVAILABLE;
+        for(int i = 0; i < COMPRESSION_ALGORITHM_MAX; i++) {
+            STREAM_CAPABILITIES c = rpt->config.compression_priorities[i];
+
+            if(!(c & STREAM_CAP_COMPRESSIONS_AVAILABLE))
+                continue;
+
+            if(compressions & c) {
+                STREAM_CAPABILITIES exclude = compressions;
+                exclude &= ~c;
+
+                rpt->capabilities &= ~exclude;
+                break;
+            }
+        }
+    }
+}
+
+bool rrdpush_compression_initialize(struct sender_state *s) {
+    rrdpush_compressor_destroy(&s->compressor);
+
+    // IMPORTANT
+    // KEEP THE SAME ORDER IN DECOMPRESSION
+
+    if(stream_has_capability(s, STREAM_CAP_ZSTD))
+        s->compressor.algorithm = COMPRESSION_ALGORITHM_ZSTD;
+    else if(stream_has_capability(s, STREAM_CAP_LZ4))
+        s->compressor.algorithm = COMPRESSION_ALGORITHM_LZ4;
+    else if(stream_has_capability(s, STREAM_CAP_BROTLI))
+        s->compressor.algorithm = COMPRESSION_ALGORITHM_BROTLI;
+    else if(stream_has_capability(s, STREAM_CAP_GZIP))
+        s->compressor.algorithm = COMPRESSION_ALGORITHM_GZIP;
+    else
+        s->compressor.algorithm = COMPRESSION_ALGORITHM_NONE;
+
+    if(s->compressor.algorithm != COMPRESSION_ALGORITHM_NONE) {
+        s->compressor.level = rrdpush_compression_levels[s->compressor.algorithm];
+        rrdpush_compressor_init(&s->compressor);
+        return true;
+    }
+
+    return false;
+}
+
+bool rrdpush_decompression_initialize(struct receiver_state *rpt) {
+    rrdpush_decompressor_destroy(&rpt->decompressor);
+
+    // IMPORTANT
+    // KEEP THE SAME ORDER IN COMPRESSION
+
+    if(stream_has_capability(rpt, STREAM_CAP_ZSTD))
+        rpt->decompressor.algorithm = COMPRESSION_ALGORITHM_ZSTD;
+    else if(stream_has_capability(rpt, STREAM_CAP_LZ4))
+        rpt->decompressor.algorithm = COMPRESSION_ALGORITHM_LZ4;
+    else if(stream_has_capability(rpt, STREAM_CAP_BROTLI))
+        rpt->decompressor.algorithm = COMPRESSION_ALGORITHM_BROTLI;
+    else if(stream_has_capability(rpt, STREAM_CAP_GZIP))
+        rpt->decompressor.algorithm = COMPRESSION_ALGORITHM_GZIP;
+    else
+        rpt->decompressor.algorithm = COMPRESSION_ALGORITHM_NONE;
+
+    if(rpt->decompressor.algorithm != COMPRESSION_ALGORITHM_NONE) {
+        rrdpush_decompressor_init(&rpt->decompressor);
+        return true;
+    }
+
+    return false;
+}
+
+/*
+* In case of stream compression buffer overflow
+* Inform the user through the error log file and
+* deactivate compression by downgrading the stream protocol.
+*/
+void rrdpush_compression_deactivate(struct sender_state *s) {
+    switch(s->compressor.algorithm) {
+        case COMPRESSION_ALGORITHM_MAX:
+        case COMPRESSION_ALGORITHM_NONE:
+            netdata_log_error("STREAM_COMPRESSION: compression error on 'host:%s' without any compression enabled. Ignoring error.",
+                    rrdhost_hostname(s->host));
+            break;
+
+        case COMPRESSION_ALGORITHM_GZIP:
+            netdata_log_error("STREAM_COMPRESSION: GZIP compression error on 'host:%s'. Disabling GZIP for this node.",
+                    rrdhost_hostname(s->host));
+            s->disabled_capabilities |= STREAM_CAP_GZIP;
+            break;
+
+        case COMPRESSION_ALGORITHM_LZ4:
+            netdata_log_error("STREAM_COMPRESSION: LZ4 compression error on 'host:%s'. Disabling ZSTD for this node.",
+                    rrdhost_hostname(s->host));
+            s->disabled_capabilities |= STREAM_CAP_LZ4;
+            break;
+
+        case COMPRESSION_ALGORITHM_ZSTD:
+            netdata_log_error("STREAM_COMPRESSION: ZSTD compression error on 'host:%s'. Disabling ZSTD for this node.",
+                    rrdhost_hostname(s->host));
+            s->disabled_capabilities |= STREAM_CAP_ZSTD;
+            break;
+
+        case COMPRESSION_ALGORITHM_BROTLI:
+            netdata_log_error("STREAM_COMPRESSION: BROTLI compression error on 'host:%s'. Disabling BROTLI for this node.",
+                    rrdhost_hostname(s->host));
+            s->disabled_capabilities |= STREAM_CAP_BROTLI;
+            break;
+    }
+}
+
+// ----------------------------------------------------------------------------
+// compressor public API
+
+void rrdpush_compressor_init(struct compressor_state *state) {
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            rrdpush_compressor_init_zstd(state);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            rrdpush_compressor_init_lz4(state);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            rrdpush_compressor_init_brotli(state);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            rrdpush_compressor_init_gzip(state);
+            break;
+    }
+
+    simple_ring_buffer_reset(&state->input);
+    simple_ring_buffer_reset(&state->output);
+}
+
+void rrdpush_compressor_destroy(struct compressor_state *state) {
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            rrdpush_compressor_destroy_zstd(state);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            rrdpush_compressor_destroy_lz4(state);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            rrdpush_compressor_destroy_brotli(state);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            rrdpush_compressor_destroy_gzip(state);
+            break;
+    }
+
+    state->initialized = false;
+
+    simple_ring_buffer_destroy(&state->input);
+    simple_ring_buffer_destroy(&state->output);
+}
+
+size_t rrdpush_compress(struct compressor_state *state, const char *data, size_t size, const char **out) {
+    size_t ret = 0;
+
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            ret = rrdpush_compress_zstd(state, data, size, out);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            ret = rrdpush_compress_lz4(state, data, size, out);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            ret = rrdpush_compress_brotli(state, data, size, out);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            ret = rrdpush_compress_gzip(state, data, size, out);
+            break;
+    }
+
+    if(unlikely(ret >= COMPRESSION_MAX_CHUNK)) {
+        netdata_log_error("RRDPUSH_COMPRESS: compressed data is %zu bytes, which is >= than the max chunk size %d",
+                ret, COMPRESSION_MAX_CHUNK);
+        return 0;
+    }
+
+    return ret;
+}
+
+// ----------------------------------------------------------------------------
+// decompressor public API
+
+void rrdpush_decompressor_destroy(struct decompressor_state *state) {
+    if(unlikely(!state->initialized))
+        return;
+
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            rrdpush_decompressor_destroy_zstd(state);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            rrdpush_decompressor_destroy_lz4(state);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            rrdpush_decompressor_destroy_brotli(state);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            rrdpush_decompressor_destroy_gzip(state);
+            break;
+    }
+
+    simple_ring_buffer_destroy(&state->output);
+
+    state->initialized = false;
+}
+
+void rrdpush_decompressor_init(struct decompressor_state *state) {
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            rrdpush_decompressor_init_zstd(state);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            rrdpush_decompressor_init_lz4(state);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            rrdpush_decompressor_init_brotli(state);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            rrdpush_decompressor_init_gzip(state);
+            break;
+    }
+
+    state->signature_size = RRDPUSH_COMPRESSION_SIGNATURE_SIZE;
+    simple_ring_buffer_reset(&state->output);
+}
+
+size_t rrdpush_decompress(struct decompressor_state *state, const char *compressed_data, size_t compressed_size) {
+    if (unlikely(state->output.read_pos != state->output.write_pos))
+        fatal("RRDPUSH_DECOMPRESS: asked to decompress new data, while there are unread data in the decompression buffer!");
+
+    size_t ret = 0;
+
+    switch(state->algorithm) {
+#ifdef ENABLE_ZSTD
+        case COMPRESSION_ALGORITHM_ZSTD:
+            ret = rrdpush_decompress_zstd(state, compressed_data, compressed_size);
+            break;
+#endif
+
+#ifdef ENABLE_LZ4
+        case COMPRESSION_ALGORITHM_LZ4:
+            ret = rrdpush_decompress_lz4(state, compressed_data, compressed_size);
+            break;
+#endif
+
+#ifdef ENABLE_BROTLI
+        case COMPRESSION_ALGORITHM_BROTLI:
+            ret = rrdpush_decompress_brotli(state, compressed_data, compressed_size);
+            break;
+#endif
+
+        default:
+        case COMPRESSION_ALGORITHM_GZIP:
+            ret = rrdpush_decompress_gzip(state, compressed_data, compressed_size);
+            break;
+    }
+
+    // for backwards compatibility we cannot check for COMPRESSION_MAX_MSG_SIZE,
+    // because old children may send this big payloads.
+    if(unlikely(ret > COMPRESSION_MAX_CHUNK)) {
+        netdata_log_error("RRDPUSH_DECOMPRESS: decompressed data is %zu bytes, which is bigger than the max msg size %d",
+                          ret, COMPRESSION_MAX_CHUNK);
+        return 0;
+    }
+
+    return ret;
+}
+
+// ----------------------------------------------------------------------------
+// unit test
+
+static inline long int my_random (void) {
+    return random();
+}
+
+void unittest_generate_random_name(char *dst, size_t size) {
+    if(size < 7)
+        size = 7;
+
+    size_t len = 5 + my_random() % (size - 6);
+
+    for(size_t i = 0; i < len ; i++) {
+        if(my_random() % 2 == 0)
+            dst[i] = 'A' + my_random() % 26;
+        else
+            dst[i] = 'a' + my_random() % 26;
+    }
+
+    dst[len] = '\0';
+}
+
+void unittest_generate_message(BUFFER *wb, time_t now_s, size_t counter) {
+    bool with_slots = true;
+    NUMBER_ENCODING integer_encoding = NUMBER_ENCODING_BASE64;
+    NUMBER_ENCODING doubles_encoding = NUMBER_ENCODING_BASE64;
+    time_t update_every = 1;
+    time_t point_end_time_s = now_s;
+    time_t wall_clock_time_s = now_s;
+    size_t chart_slot = counter + 1;
+    size_t dimensions = 2 + my_random() % 5;
+    char chart[RRD_ID_LENGTH_MAX + 1] = "name";
+    unittest_generate_random_name(chart, 5 + my_random() % 30);
+
+    buffer_fast_strcat(wb, PLUGINSD_KEYWORD_BEGIN_V2, sizeof(PLUGINSD_KEYWORD_BEGIN_V2) - 1);
+
+    if(with_slots) {
+        buffer_fast_strcat(wb, " "PLUGINSD_KEYWORD_SLOT":", sizeof(PLUGINSD_KEYWORD_SLOT) - 1 + 2);
+        buffer_print_uint64_encoded(wb, integer_encoding, chart_slot);
+    }
+
+    buffer_fast_strcat(wb, " '", 2);
+    buffer_strcat(wb, chart);
+    buffer_fast_strcat(wb, "' ", 2);
+    buffer_print_uint64_encoded(wb, integer_encoding, update_every);
+    buffer_fast_strcat(wb, " ", 1);
+    buffer_print_uint64_encoded(wb, integer_encoding, point_end_time_s);
+    buffer_fast_strcat(wb, " ", 1);
+    if(point_end_time_s == wall_clock_time_s)
+        buffer_fast_strcat(wb, "#", 1);
+    else
+        buffer_print_uint64_encoded(wb, integer_encoding, wall_clock_time_s);
+    buffer_fast_strcat(wb, "\n", 1);
+
+
+    for(size_t d = 0; d < dimensions ;d++) {
+        size_t dim_slot = d + 1;
+        char dim_id[RRD_ID_LENGTH_MAX + 1] = "dimension";
+        unittest_generate_random_name(dim_id, 10 + my_random() % 20);
+        int64_t last_collected_value = (my_random() % 2 == 0) ? (int64_t)(counter + d) : (int64_t)my_random();
+        NETDATA_DOUBLE value = (my_random() % 2 == 0) ? (NETDATA_DOUBLE)my_random() / ((NETDATA_DOUBLE)my_random() + 1) : (NETDATA_DOUBLE)last_collected_value;
+        SN_FLAGS flags = (my_random() % 1000 == 0) ? SN_FLAG_NONE : SN_FLAG_NOT_ANOMALOUS;
+
+        buffer_fast_strcat(wb, PLUGINSD_KEYWORD_SET_V2, sizeof(PLUGINSD_KEYWORD_SET_V2) - 1);
+
+        if(with_slots) {
+            buffer_fast_strcat(wb, " "PLUGINSD_KEYWORD_SLOT":", sizeof(PLUGINSD_KEYWORD_SLOT) - 1 + 2);
+            buffer_print_uint64_encoded(wb, integer_encoding, dim_slot);
+        }
+
+        buffer_fast_strcat(wb, " '", 2);
+        buffer_strcat(wb, dim_id);
+        buffer_fast_strcat(wb, "' ", 2);
+        buffer_print_int64_encoded(wb, integer_encoding, last_collected_value);
+        buffer_fast_strcat(wb, " ", 1);
+
+        if((NETDATA_DOUBLE)last_collected_value == value)
+            buffer_fast_strcat(wb, "#", 1);
+        else
+            buffer_print_netdata_double_encoded(wb, doubles_encoding, value);
+
+        buffer_fast_strcat(wb, " ", 1);
+        buffer_print_sn_flags(wb, flags, true);
+        buffer_fast_strcat(wb, "\n", 1);
+    }
+
+    buffer_fast_strcat(wb, PLUGINSD_KEYWORD_END_V2 "\n", sizeof(PLUGINSD_KEYWORD_END_V2) - 1 + 1);
+}
+
+int unittest_rrdpush_compression_speed(compression_algorithm_t algorithm, const char *name) {
+    fprintf(stderr, "\nTesting streaming compression speed with %s\n", name);
+
+    struct compressor_state cctx =  {
+            .initialized = false,
+            .algorithm = algorithm,
+    };
+    struct decompressor_state dctx = {
+            .initialized = false,
+            .algorithm = algorithm,
+    };
+
+    rrdpush_compressor_init(&cctx);
+    rrdpush_decompressor_init(&dctx);
+
+    int errors = 0;
+
+    BUFFER *wb = buffer_create(COMPRESSION_MAX_MSG_SIZE, NULL);
+    time_t now_s = now_realtime_sec();
+    usec_t compression_ut = 0;
+    usec_t decompression_ut = 0;
+    size_t bytes_compressed = 0;
+    size_t bytes_uncompressed = 0;
+
+    usec_t compression_started_ut = now_monotonic_usec();
+    usec_t decompression_started_ut = compression_started_ut;
+
+    for(int i = 0; i < 10000 ;i++) {
+        compression_started_ut = now_monotonic_usec();
+        decompression_ut += compression_started_ut - decompression_started_ut;
+
+        buffer_flush(wb);
+        while(buffer_strlen(wb) < COMPRESSION_MAX_MSG_SIZE - 1024)
+            unittest_generate_message(wb, now_s, i);
+
+        const char *txt = buffer_tostring(wb);
+        size_t txt_len = buffer_strlen(wb);
+        bytes_uncompressed += txt_len;
+
+        const char *out;
+        size_t size = rrdpush_compress(&cctx, txt, txt_len, &out);
+
+        bytes_compressed += size;
+        decompression_started_ut = now_monotonic_usec();
+        compression_ut += decompression_started_ut - compression_started_ut;
+
+        if(size == 0) {
+            fprintf(stderr, "iteration %d: compressed size %zu is zero\n",
+                    i, size);
+            errors++;
+            goto cleanup;
+        }
+        else if(size >= COMPRESSION_MAX_CHUNK) {
+            fprintf(stderr, "iteration %d: compressed size %zu exceeds max allowed size\n",
+                    i, size);
+            errors++;
+            goto cleanup;
+        }
+        else {
+            size_t dtxt_len = rrdpush_decompress(&dctx, out, size);
+            char *dtxt = (char *) &dctx.output.data[dctx.output.read_pos];
+
+            if(rrdpush_decompressed_bytes_in_buffer(&dctx) != dtxt_len) {
+                fprintf(stderr, "iteration %d: decompressed size %zu does not rrdpush_decompressed_bytes_in_buffer() %zu\n",
+                        i, dtxt_len, rrdpush_decompressed_bytes_in_buffer(&dctx)
+                       );
+                errors++;
+                goto cleanup;
+            }
+
+            if(!dtxt_len) {
+                fprintf(stderr, "iteration %d: decompressed size is zero\n", i);
+                errors++;
+                goto cleanup;
+            }
+            else if(dtxt_len != txt_len) {
+                fprintf(stderr, "iteration %d: decompressed size %zu does not match original size %zu\n",
+                        i, dtxt_len, txt_len
+                       );
+                errors++;
+                goto cleanup;
+            }
+            else {
+                if(memcmp(txt, dtxt, txt_len) != 0) {
+                    fprintf(stderr, "iteration %d: decompressed data '%s' do not match original data length %zu\n",
+                            i, dtxt, txt_len);
+                    errors++;
+                    goto cleanup;
+                }
+            }
+        }
+
+        // here we are supposed to copy the data and advance the position
+        dctx.output.read_pos += rrdpush_decompressed_bytes_in_buffer(&dctx);
+    }
+
+cleanup:
+    rrdpush_compressor_destroy(&cctx);
+    rrdpush_decompressor_destroy(&dctx);
+
+    if(errors)
+        fprintf(stderr, "Compression with %s: FAILED (%d errors)\n", name, errors);
+    else
+        fprintf(stderr, "Compression with %s: OK "
+                        "(compression %zu usec, decompression %zu usec, bytes raw %zu, compressed %zu, savings ratio %0.2f%%)\n",
+                        name, compression_ut, decompression_ut,
+                        bytes_uncompressed, bytes_compressed,
+                        100.0 - (double)bytes_compressed * 100.0 / (double)bytes_uncompressed);
+
+    return errors;
+}
+
+int unittest_rrdpush_compression(compression_algorithm_t algorithm, const char *name) {
+    fprintf(stderr, "\nTesting streaming compression with %s\n", name);
+
+    struct compressor_state cctx =  {
+            .initialized = false,
+            .algorithm = algorithm,
+    };
+    struct decompressor_state dctx = {
+            .initialized = false,
+            .algorithm = algorithm,
+    };
+
+    char txt[COMPRESSION_MAX_MSG_SIZE];
+
+    rrdpush_compressor_init(&cctx);
+    rrdpush_decompressor_init(&dctx);
+
+    int errors = 0;
+
+    memset(txt, '=', COMPRESSION_MAX_MSG_SIZE);
+
+    for(int i = 0; i < COMPRESSION_MAX_MSG_SIZE ;i++) {
+        txt[i] = 'A' + (i % 26);
+        size_t txt_len = i + 1;
+
+        const char *out;
+        size_t size = rrdpush_compress(&cctx, txt, txt_len, &out);
+
+        if(size == 0) {
+            fprintf(stderr, "iteration %d: compressed size %zu is zero\n",
+                    i, size);
+            errors++;
+            goto cleanup;
+        }
+        else if(size >= COMPRESSION_MAX_CHUNK) {
+            fprintf(stderr, "iteration %d: compressed size %zu exceeds max allowed size\n",
+                    i, size);
+            errors++;
+            goto cleanup;
+        }
+        else {
+            size_t dtxt_len = rrdpush_decompress(&dctx, out, size);
+            char *dtxt = (char *) &dctx.output.data[dctx.output.read_pos];
+
+            if(rrdpush_decompressed_bytes_in_buffer(&dctx) != dtxt_len) {
+                fprintf(stderr, "iteration %d: decompressed size %zu does not rrdpush_decompressed_bytes_in_buffer() %zu\n",
+                        i, dtxt_len, rrdpush_decompressed_bytes_in_buffer(&dctx)
+                       );
+                errors++;
+                goto cleanup;
+            }
+
+            if(!dtxt_len) {
+                fprintf(stderr, "iteration %d: decompressed size is zero\n", i);
+                errors++;
+                goto cleanup;
+            }
+            else if(dtxt_len != txt_len) {
+                fprintf(stderr, "iteration %d: decompressed size %zu does not match original size %zu\n",
+                        i, dtxt_len, txt_len
+                       );
+                errors++;
+                goto cleanup;
+            }
+            else {
+                if(memcmp(txt, dtxt, txt_len) != 0) {
+                    txt[txt_len] = '\0';
+                    dtxt[txt_len + 5] = '\0';
+
+                    fprintf(stderr, "iteration %d: decompressed data '%s' do not match original data '%s' of length %zu\n",
+                            i, dtxt, txt, txt_len);
+                    errors++;
+                    goto cleanup;
+                }
+            }
+        }
+
+        // fill the compressed buffer with garbage
+        memset((void *)out, 'x', size);
+
+        // here we are supposed to copy the data and advance the position
+        dctx.output.read_pos += rrdpush_decompressed_bytes_in_buffer(&dctx);
+    }
+
+cleanup:
+    rrdpush_compressor_destroy(&cctx);
+    rrdpush_decompressor_destroy(&dctx);
+
+    if(errors)
+        fprintf(stderr, "Compression with %s: FAILED (%d errors)\n", name, errors);
+    else
+        fprintf(stderr, "Compression with %s: OK\n", name);
+
+    return errors;
+}
+
+int unittest_rrdpush_compressions(void) {
+    int ret = 0;
+
+    ret += unittest_rrdpush_compression(COMPRESSION_ALGORITHM_ZSTD, "ZSTD");
+    ret += unittest_rrdpush_compression(COMPRESSION_ALGORITHM_LZ4, "LZ4");
+    ret += unittest_rrdpush_compression(COMPRESSION_ALGORITHM_BROTLI, "BROTLI");
+    ret += unittest_rrdpush_compression(COMPRESSION_ALGORITHM_GZIP, "GZIP");
+
+    ret += unittest_rrdpush_compression_speed(COMPRESSION_ALGORITHM_ZSTD, "ZSTD");
+    ret += unittest_rrdpush_compression_speed(COMPRESSION_ALGORITHM_LZ4, "LZ4");
+    ret += unittest_rrdpush_compression_speed(COMPRESSION_ALGORITHM_BROTLI, "BROTLI");
+    ret += unittest_rrdpush_compression_speed(COMPRESSION_ALGORITHM_GZIP, "GZIP");
+
+    return ret;
+}