refactor(lib, hicn-light, vpp, hiperf): HICN-723

 - move infra data structure into the shared lib
 - new packet cache using double hashing and lookup on prefix suffix
 - testing updates
 - authenticated requests using interest manifests

Co-authored-by: Mauro Sardara <msardara@cisco.com>
Co-authored-by: Jordan Augé <jordan.auge+fdio@cisco.com>
Co-authored-by: Michele Papalini <micpapal@cisco.com>
Co-authored-by: Olivier Roques <oroques+fdio@cisco.com>
Co-authored-by: Enrico Loparco <eloparco@cisco.com>

Change-Id: Iaddebfe6aa5279ea8553433b0f519578f6b9ccd9
Signed-off-by: Luca Muscariello <muscariello@ieee.org>

4 files changed, 823 insertions, 0 deletions

diff --git a/telemetry/kafka-collectd/CMakeLists.txt b/telemetry/kafka-collectd/CMakeLists.txt
new file mode 100644
index 000000000..f1ff81117
--- /dev/null
+++ b/telemetry/kafka-collectd/CMakeLists.txt
@@ -0,0 +1,62 @@
+# Copyright (c) 2022 Cisco and/or its affiliates.
+
+##############################################################
+# Source files
+##############################################################
+file(GLOB_RECURSE COLLECTD_UTILS_SOURCES "${THIRD_PARTY_INCLUDE_DIRS}/utils/cmds/*.c")
+
+list(APPEND SOURCE_FILES
+  ${CMAKE_CURRENT_SOURCE_DIR}/write_kafka_line_protocol.c
+  ${THIRD_PARTY_INCLUDE_DIRS}/utils/format_json/format_json.c
+  ${THIRD_PARTY_INCLUDE_DIRS}/utils/format_graphite/format_graphite.c
+  ${CMAKE_CURRENT_SOURCE_DIR}/format_influxdb.c
+  ${COLLECTD_UTILS_SOURCES}
+)
+
+
+##############################################################
+# Include dirs
+##############################################################
+list(APPEND INCLUDE_DIRS
+  PRIVATE ${COLLECTD_INCLUDE_DIRS}
+  PRIVATE ${THIRD_PARTY_INCLUDE_DIRS}
+)
+
+
+##############################################################
+# Libraries
+##############################################################
+find_package(RdKafka ${RDKAFKA_DEFAULT_VERSION} REQUIRED)
+find_library(YAJL_LIB libyajl.so REQUIRED)
+
+list (APPEND LIBRARIES
+  ${YAJL_LIB}
+  ${RdKafka_LIBRARY_PATH}
+)
+
+
+##############################################################
+# Compiler options
+##############################################################
+list(APPEND COMPILER_OPTIONS
+  ${DEFAULT_COMPILER_OPTIONS}
+  ${COLLECTD_COMPILER_OPTIONS}
+)
+
+
+##############################################################
+# Build library
+##############################################################
+build_library(${KAFKA_TELEMETRY}
+  SHARED
+  EMPTY_PREFIX
+  SOURCES ${SOURCE_FILES}
+  LINK_LIBRARIES ${LIBRARIES}
+  INCLUDE_DIRS
+    PRIVATE ${INCLUDE_DIRS}
+  INSTALL_FULL_PATH_DIR ${COLLECTD_PLUGIN_DIR}
+  COMPONENT ${COLLECTD_PLUGINS}
+  DEPENDS ${DEPENDENCIES}
+  LINK_FLAGS ${LINK_FLAGS}
+  COMPILE_OPTIONS ${COMPILER_OPTIONS}
+)
diff --git a/telemetry/kafka-collectd/format_influxdb.c b/telemetry/kafka-collectd/format_influxdb.c
new file mode 100644
index 000000000..f7ff29501
--- /dev/null
+++ b/telemetry/kafka-collectd/format_influxdb.c
@@ -0,0 +1,190 @@
+/**
+ * collectd - src/utils_format_influxdb.c
+ * Copyright (C) 2007-2009  Florian octo Forster
+ * Copyright (C) 2009       Aman Gupta
+ * Copyright (C) 2019       Carlos Peon Costa
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; only version 2 of the License is applicable.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Florian octo Forster <octo at collectd.org>
+ *   Aman Gupta <aman at tmm1.net>
+ *   Carlos Peon Costa <carlospeon at gmail.com>
+ *   multiple Server directives by:
+ *   Paul (systemcrash) <newtwen thatfunny_at_symbol gmail.com>
+ **/
+
+#include "format_influxdb.h"
+
+#include "collectd.h"
+#include "plugin.h"
+#include "utils/common/common.h"
+#include "utils/metadata/meta_data.h"
+#include "utils_cache.h"
+
+static int format_influxdb_escape_string(char *buffer, size_t buffer_size,
+                                         const char *string) {
+  if ((buffer == NULL) || (string == NULL)) return -EINVAL;
+
+  if (buffer_size < 3) return -ENOMEM;
+
+  int dst_pos = 0;
+
+#define BUFFER_ADD(c)                   \
+  do {                                  \
+    if (dst_pos >= (buffer_size - 1)) { \
+      buffer[buffer_size - 1] = '\0';   \
+      return -ENOMEM;                   \
+    }                                   \
+    buffer[dst_pos] = (c);              \
+    dst_pos++;                          \
+  } while (0)
+
+  /* Escape special characters */
+  for (int src_pos = 0; string[src_pos] != 0; src_pos++) {
+    if ((string[src_pos] == '\\') || (string[src_pos] == ' ') ||
+        (string[src_pos] == ',') || (string[src_pos] == '=') ||
+        (string[src_pos] == '"')) {
+      BUFFER_ADD('\\');
+      BUFFER_ADD(string[src_pos]);
+    } else
+      BUFFER_ADD(string[src_pos]);
+  } /* for */
+  buffer[dst_pos] = 0;
+
+#undef BUFFER_ADD
+
+  return dst_pos;
+} /* int format_influxdb_escape_string */
+
+int format_influxdb_value_list(
+    char *buffer, int buffer_len, const data_set_t *ds, const value_list_t *vl,
+    bool store_rates, format_influxdb_time_precision_t time_precision) {
+  int status;
+  int offset = 0;
+  gauge_t *rates = NULL;
+  bool have_values = false;
+
+  assert(0 == strcmp(ds->type, vl->type));
+
+#define BUFFER_ADD_ESCAPE(...)                                                \
+  do {                                                                        \
+    status = format_influxdb_escape_string(buffer + offset,                   \
+                                           buffer_len - offset, __VA_ARGS__); \
+    if (status < 0) return status;                                            \
+    offset += status;                                                         \
+  } while (0)
+
+#define BUFFER_ADD(...)                                                   \
+  do {                                                                    \
+    status = snprintf(buffer + offset, buffer_len - offset, __VA_ARGS__); \
+    if ((status < 0) || (status >= (buffer_len - offset))) {              \
+      sfree(rates);                                                       \
+      return -ENOMEM;                                                     \
+    }                                                                     \
+    offset += status;                                                     \
+  } while (0)
+
+  assert(vl->type);
+  BUFFER_ADD_ESCAPE(vl->type);
+  BUFFER_ADD(",host=");
+  BUFFER_ADD_ESCAPE(vl->host);
+  if (vl->meta) {
+    char **toc;
+    int n = meta_data_toc(vl->meta, &toc);
+
+    for (int i = 0; i < n; i++) {
+      char *key = toc[i];
+      char *value;
+
+      if (meta_data_as_string(vl->meta, key, &value) == 0) {
+        BUFFER_ADD(",");
+        BUFFER_ADD_ESCAPE(key);
+        BUFFER_ADD("=");
+        BUFFER_ADD_ESCAPE(value);
+        free(value);
+      }
+      free(toc[i]);
+    }
+
+    if (n != 0) free(toc);
+  }
+
+  BUFFER_ADD(" ");
+  for (size_t i = 0; i < ds->ds_num; i++) {
+    if ((ds->ds[i].type != DS_TYPE_COUNTER) &&
+        (ds->ds[i].type != DS_TYPE_GAUGE) &&
+        (ds->ds[i].type != DS_TYPE_DERIVE) &&
+        (ds->ds[i].type != DS_TYPE_ABSOLUTE)) {
+      sfree(rates);
+      return -EINVAL;
+    }
+
+    if (ds->ds[i].type == DS_TYPE_GAUGE) {
+      if (isnan(vl->values[i].gauge)) continue;
+      if (have_values) BUFFER_ADD(",");
+      BUFFER_ADD("%s=%lf", ds->ds[i].name, vl->values[i].gauge);
+      have_values = true;
+    } else if (store_rates) {
+      if (rates == NULL) rates = uc_get_rate(ds, vl);
+      if (rates == NULL) {
+        WARNING(
+            "format_influxdb: "
+            "uc_get_rate failed.");
+        return -EINVAL;
+      }
+      if (isnan(rates[i])) continue;
+      if (have_values) BUFFER_ADD(",");
+      BUFFER_ADD("%s=%lf", ds->ds[i].name, rates[i]);
+      have_values = true;
+    } else if (ds->ds[i].type == DS_TYPE_COUNTER) {
+      if (have_values) BUFFER_ADD(",");
+      BUFFER_ADD("%s=%" PRIu64 "i", ds->ds[i].name,
+                 (uint64_t)vl->values[i].counter);
+      have_values = true;
+    } else if (ds->ds[i].type == DS_TYPE_DERIVE) {
+      if (have_values) BUFFER_ADD(",");
+      BUFFER_ADD("%s=%" PRIi64 "i", ds->ds[i].name, vl->values[i].derive);
+      have_values = true;
+    } else if (ds->ds[i].type == DS_TYPE_ABSOLUTE) {
+      if (have_values) BUFFER_ADD(",");
+      BUFFER_ADD("%s=%" PRIu64 "i", ds->ds[i].name, vl->values[i].absolute);
+      have_values = true;
+    }
+
+  } /* for ds->ds_num */
+  sfree(rates);
+
+  if (!have_values) return 0;
+
+  uint64_t influxdb_time = 0;
+  switch (time_precision) {
+    case NS:
+      influxdb_time = CDTIME_T_TO_NS(vl->time);
+      break;
+    case US:
+      influxdb_time = CDTIME_T_TO_US(vl->time);
+      break;
+    case MS:
+      influxdb_time = CDTIME_T_TO_MS(vl->time);
+      break;
+  }
+
+  BUFFER_ADD(" %" PRIu64 "\n", influxdb_time);
+
+#undef BUFFER_ADD_ESCAPE
+#undef BUFFER_ADD
+
+  return offset;
+} /* int format_influxdb_value_list */
diff --git a/telemetry/kafka-collectd/format_influxdb.h b/telemetry/kafka-collectd/format_influxdb.h
new file mode 100644
index 000000000..fd298f11b
--- /dev/null
+++ b/telemetry/kafka-collectd/format_influxdb.h
@@ -0,0 +1,45 @@
+/**
+ * collectd - src/utils_format_influxdb.h
+ * Copyright (C) 2007-2009  Florian octo Forster
+ * Copyright (C) 2009       Aman Gupta
+ * Copyright (C) 2019       Carlos Peon Costa
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; only version 2 of the License is applicable.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Florian octo Forster <octo at collectd.org>
+ *   Aman Gupta <aman at tmm1.net>
+ *   Carlos Peon Costa <carlospeon at gmail.com>
+ *   multiple Server directives by:
+ *   Paul (systemcrash) <newtwen thatfunny_at_symbol gmail.com>
+ **/
+
+#ifndef UTILS_FORMAT_INFLUXDB_H
+#define UTILS_FORMAT_INFLUXDB_H 1
+
+#include "collectd.h"
+#include "plugin.h"
+
+typedef enum {
+  NS,
+  US,
+  MS,
+} format_influxdb_time_precision_t;
+
+int format_influxdb_value_list(char *buffer, int buffer_len,
+                               const data_set_t *ds, const value_list_t *vl,
+                               bool store_rates,
+                               format_influxdb_time_precision_t time_precision);
+
+#endif /* UTILS_FORMAT_INFLUXDB_H */
diff --git a/telemetry/kafka-collectd/write_kafka_line_protocol.c b/telemetry/kafka-collectd/write_kafka_line_protocol.c
new file mode 100644
index 000000000..5eb7b520d
--- /dev/null
+++ b/telemetry/kafka-collectd/write_kafka_line_protocol.c
@@ -0,0 +1,526 @@
+/**
+ * collectd - src/write_kafka.c
+ * Copyright (C) 2014       Pierre-Yves Ritschard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *   Pierre-Yves Ritschard <pyr at spootnik.org>
+ */
+
+#include <errno.h>
+#include <librdkafka/rdkafka.h>
+#include <stdint.h>
+
+#include "../data_model.h"
+#include "collectd.h"
+#include "format_influxdb.h"
+#include "plugin.h"
+#include "utils/cmds/putval.h"
+#include "utils/common/common.h"
+#include "utils/format_graphite/format_graphite.h"
+#include "utils/format_json/format_json.h"
+#include "utils_random.h"
+
+struct kafka_topic_context {
+#define KAFKA_FORMAT_JSON 0
+#define KAFKA_FORMAT_COMMAND 1
+#define KAFKA_FORMAT_GRAPHITE 2
+#define KAFKA_FORMAT_INFLUXDB 3
+  uint8_t format;
+  unsigned int graphite_flags;
+  bool store_rates;
+  rd_kafka_topic_conf_t *conf;
+  rd_kafka_topic_t *topic;
+  rd_kafka_conf_t *kafka_conf;
+  rd_kafka_t *kafka;
+  char *key;
+  char *prefix;
+  char *postfix;
+  char escape_char;
+  char *topic_name;
+  pthread_mutex_t lock;
+};
+
+static int kafka_handle(struct kafka_topic_context *);
+static int kafka_write(const data_set_t *, const value_list_t *, user_data_t *);
+static int32_t kafka_partition(const rd_kafka_topic_t *, const void *, size_t,
+                               int32_t, void *, void *);
+
+/* Version 0.9.0 of librdkafka deprecates rd_kafka_set_logger() in favor of
+ * rd_kafka_conf_set_log_cb(). This is to make sure we're not using the
+ * deprecated function. */
+#ifdef HAVE_LIBRDKAFKA_LOG_CB
+#undef HAVE_LIBRDKAFKA_LOGGER
+#endif
+
+#if defined(HAVE_LIBRDKAFKA_LOGGER) || defined(HAVE_LIBRDKAFKA_LOG_CB)
+static void kafka_log(const rd_kafka_t *, int, const char *, const char *);
+
+static void kafka_log(const rd_kafka_t *rkt, int level, const char *fac,
+                      const char *msg) {
+  plugin_log(level, "%s", msg);
+}
+#endif
+
+static rd_kafka_resp_err_t kafka_error() {
+#if RD_KAFKA_VERSION >= 0x000b00ff
+  return rd_kafka_last_error();
+#else
+  return rd_kafka_errno2err(errno);
+#endif
+}
+
+static uint32_t kafka_hash(const char *keydata, size_t keylen) {
+  uint32_t hash = 5381;
+  for (; keylen > 0; keylen--)
+    hash = ((hash << 5) + hash) + keydata[keylen - 1];
+  return hash;
+}
+
+/* 31 bit -> 4 byte -> 8 byte hex string + null byte */
+#define KAFKA_RANDOM_KEY_SIZE 9
+#define KAFKA_RANDOM_KEY_BUFFER \
+  (char[KAFKA_RANDOM_KEY_SIZE]) { "" }
+static char *kafka_random_key(char buffer[static KAFKA_RANDOM_KEY_SIZE]) {
+  ssnprintf(buffer, KAFKA_RANDOM_KEY_SIZE, "%08" PRIX32, cdrand_u());
+  return buffer;
+}
+
+static int32_t kafka_partition(const rd_kafka_topic_t *rkt, const void *keydata,
+                               size_t keylen, int32_t partition_cnt, void *p,
+                               void *m) {
+  uint32_t key = kafka_hash(keydata, keylen);
+  uint32_t target = key % partition_cnt;
+  int32_t i = partition_cnt;
+
+  while (--i > 0 && !rd_kafka_topic_partition_available(rkt, target)) {
+    target = (target + 1) % partition_cnt;
+  }
+  return target;
+}
+
+static int kafka_handle(struct kafka_topic_context *ctx) /* {{{ */
+{
+  char errbuf[1024];
+  rd_kafka_conf_t *conf;
+  rd_kafka_topic_conf_t *topic_conf;
+
+  if (ctx->kafka != NULL && ctx->topic != NULL) return 0;
+
+  if (ctx->kafka == NULL) {
+    if ((conf = rd_kafka_conf_dup(ctx->kafka_conf)) == NULL) {
+      ERROR("write_kafka plugin: cannot duplicate kafka config");
+      return 1;
+    }
+
+    if ((ctx->kafka = rd_kafka_new(RD_KAFKA_PRODUCER, conf, errbuf,
+                                   sizeof(errbuf))) == NULL) {
+      ERROR("write_kafka plugin: cannot create kafka handle.");
+      return 1;
+    }
+
+    rd_kafka_conf_destroy(ctx->kafka_conf);
+    ctx->kafka_conf = NULL;
+
+    INFO("write_kafka plugin: created KAFKA handle : %s",
+         rd_kafka_name(ctx->kafka));
+
+#if defined(HAVE_LIBRDKAFKA_LOGGER) && !defined(HAVE_LIBRDKAFKA_LOG_CB)
+    rd_kafka_set_logger(ctx->kafka, kafka_log);
+#endif
+  }
+
+  if (ctx->topic == NULL) {
+    if ((topic_conf = rd_kafka_topic_conf_dup(ctx->conf)) == NULL) {
+      ERROR("write_kafka plugin: cannot duplicate kafka topic config");
+      return 1;
+    }
+
+    if ((ctx->topic = rd_kafka_topic_new(ctx->kafka, ctx->topic_name,
+                                         topic_conf)) == NULL) {
+      ERROR("write_kafka plugin: cannot create topic : %s\n",
+            rd_kafka_err2str(kafka_error()));
+      return errno;
+    }
+
+    rd_kafka_topic_conf_destroy(ctx->conf);
+    ctx->conf = NULL;
+
+    INFO("write_kafka plugin: handle created for topic : %s",
+         rd_kafka_topic_name(ctx->topic));
+  }
+
+  return 0;
+
+} /* }}} int kafka_handle */
+
+static int kafka_write(const data_set_t *ds, /* {{{ */
+                       const value_list_t *vl, user_data_t *ud) {
+  int status = 0;
+  void *key;
+  size_t keylen = 0;
+  char buffer[8192];
+  size_t bfree = sizeof(buffer);
+  size_t bfill = 0;
+  size_t blen = 0;
+  struct kafka_topic_context *ctx = ud->data;
+
+  if ((ds == NULL) || (vl == NULL) || (ctx == NULL)) return EINVAL;
+
+  pthread_mutex_lock(&ctx->lock);
+  status = kafka_handle(ctx);
+  pthread_mutex_unlock(&ctx->lock);
+  if (status != 0) return status;
+
+  bzero(buffer, sizeof(buffer));
+
+  switch (ctx->format) {
+    case KAFKA_FORMAT_COMMAND:
+      status = cmd_create_putval(buffer, sizeof(buffer), ds, vl);
+      if (status != 0) {
+        ERROR("write_kafka plugin: cmd_create_putval failed with status %i.",
+              status);
+        return status;
+      }
+      blen = strlen(buffer);
+      break;
+    case KAFKA_FORMAT_JSON:
+      format_json_initialize(buffer, &bfill, &bfree);
+      format_json_value_list(buffer, &bfill, &bfree, ds, vl, ctx->store_rates);
+      format_json_finalize(buffer, &bfill, &bfree);
+      blen = strlen(buffer);
+      break;
+    case KAFKA_FORMAT_GRAPHITE:
+      status =
+          format_graphite(buffer, sizeof(buffer), ds, vl, ctx->prefix,
+                          ctx->postfix, ctx->escape_char, ctx->graphite_flags);
+      if (status != 0) {
+        ERROR("write_kafka plugin: format_graphite failed with status %i.",
+              status);
+        return status;
+      }
+      blen = strlen(buffer);
+      break;
+    case KAFKA_FORMAT_INFLUXDB: {
+      // Decide format depending on the topic
+      // (to handle multilple topics w/ different formats);
+      // Comment this part to use the stream topic as default for other
+      // collectd plugins (e.g. cpu, mem)
+      char *topic = NULL;
+      int rc = meta_data_get_string(vl->meta, KAFKA_TOPIC_KEY, &topic);
+      if (rc != 0 || topic == NULL) return 0;
+      if (strcasecmp(KAFKA_STREAM_TOPIC, topic) != 0) {
+        free(topic);
+        return 0;
+      }
+      meta_data_delete(vl->meta, KAFKA_TOPIC_KEY);
+
+      status =
+          format_influxdb_value_list(buffer, sizeof(buffer), ds, vl, false, NS);
+      if (status <= 0) {
+        ERROR("write_kafka plugin: format_influxdb failed with status %i.",
+              status);
+        return status;
+      }
+      blen = strlen(buffer);
+
+      // Print without newline
+      buffer[blen - 1] = 0;
+      INFO("%s", buffer);
+      buffer[blen - 1] = '\n';
+
+      break;
+    }
+    default:
+      ERROR("write_kafka plugin: invalid format %i.", ctx->format);
+      return -1;
+  }
+
+  key =
+      (ctx->key != NULL) ? ctx->key : kafka_random_key(KAFKA_RANDOM_KEY_BUFFER);
+  keylen = strlen(key);
+
+  rd_kafka_produce(ctx->topic, RD_KAFKA_PARTITION_UA, RD_KAFKA_MSG_F_COPY,
+                   buffer, blen, key, keylen, NULL);
+
+  return status;
+} /* }}} int kafka_write */
+
+static void kafka_topic_context_free(void *p) /* {{{ */
+{
+  struct kafka_topic_context *ctx = p;
+
+  if (ctx == NULL) return;
+
+  if (ctx->topic_name != NULL) sfree(ctx->topic_name);
+  if (ctx->topic != NULL) rd_kafka_topic_destroy(ctx->topic);
+  if (ctx->conf != NULL) rd_kafka_topic_conf_destroy(ctx->conf);
+  if (ctx->kafka_conf != NULL) rd_kafka_conf_destroy(ctx->kafka_conf);
+  if (ctx->kafka != NULL) rd_kafka_destroy(ctx->kafka);
+
+  sfree(ctx);
+} /* }}} void kafka_topic_context_free */
+
+static void kafka_config_topic(rd_kafka_conf_t *conf,
+                               oconfig_item_t *ci) /* {{{ */
+{
+  int status;
+  struct kafka_topic_context *tctx;
+  char *key = NULL;
+  char *val;
+  char callback_name[DATA_MAX_NAME_LEN];
+  char errbuf[1024];
+  oconfig_item_t *child;
+  rd_kafka_conf_res_t ret;
+
+  if ((tctx = calloc(1, sizeof(*tctx))) == NULL) {
+    ERROR("write_kafka plugin: calloc failed.");
+    return;
+  }
+
+  tctx->escape_char = '.';
+  tctx->store_rates = true;
+  tctx->format = KAFKA_FORMAT_JSON;
+  tctx->key = NULL;
+
+  if ((tctx->kafka_conf = rd_kafka_conf_dup(conf)) == NULL) {
+    sfree(tctx);
+    ERROR("write_kafka plugin: cannot allocate memory for kafka config");
+    return;
+  }
+
+#ifdef HAVE_LIBRDKAFKA_LOG_CB
+  rd_kafka_conf_set_log_cb(tctx->kafka_conf, kafka_log);
+#endif
+
+  if ((tctx->conf = rd_kafka_topic_conf_new()) == NULL) {
+    rd_kafka_conf_destroy(tctx->kafka_conf);
+    sfree(tctx);
+    ERROR("write_kafka plugin: cannot create topic configuration.");
+    return;
+  }
+
+  if (ci->values_num != 1) {
+    WARNING("kafka topic name needed.");
+    goto errout;
+  }
+
+  if (ci->values[0].type != OCONFIG_TYPE_STRING) {
+    WARNING("kafka topic needs a string argument.");
+    goto errout;
+  }
+
+  if ((tctx->topic_name = strdup(ci->values[0].value.string)) == NULL) {
+    ERROR("write_kafka plugin: cannot copy topic name.");
+    goto errout;
+  }
+
+  for (int i = 0; i < ci->children_num; i++) {
+    /*
+     * The code here could be simplified but makes room
+     * for easy adding of new options later on.
+     */
+    child = &ci->children[i];
+    status = 0;
+
+    if (strcasecmp("Property", child->key) == 0) {
+      if (child->values_num != 2) {
+        WARNING("kafka properties need both a key and a value.");
+        goto errout;
+      }
+      if (child->values[0].type != OCONFIG_TYPE_STRING ||
+          child->values[1].type != OCONFIG_TYPE_STRING) {
+        WARNING("kafka properties needs string arguments.");
+        goto errout;
+      }
+      key = child->values[0].value.string;
+      val = child->values[1].value.string;
+      ret =
+          rd_kafka_topic_conf_set(tctx->conf, key, val, errbuf, sizeof(errbuf));
+      if (ret != RD_KAFKA_CONF_OK) {
+        WARNING("cannot set kafka topic property %s to %s: %s.", key, val,
+                errbuf);
+        goto errout;
+      }
+
+    } else if (strcasecmp("Key", child->key) == 0) {
+      if (cf_util_get_string(child, &tctx->key) != 0) continue;
+      if (strcasecmp("Random", tctx->key) == 0) {
+        sfree(tctx->key);
+        tctx->key = strdup(kafka_random_key(KAFKA_RANDOM_KEY_BUFFER));
+      }
+    } else if (strcasecmp("Format", child->key) == 0) {
+      status = cf_util_get_string(child, &key);
+      if (status != 0) goto errout;
+
+      assert(key != NULL);
+
+      if (strcasecmp(key, "Command") == 0) {
+        tctx->format = KAFKA_FORMAT_COMMAND;
+
+      } else if (strcasecmp(key, "Graphite") == 0) {
+        tctx->format = KAFKA_FORMAT_GRAPHITE;
+
+      } else if (strcasecmp(key, "Json") == 0) {
+        tctx->format = KAFKA_FORMAT_JSON;
+
+      } else if (strcasecmp(key, "InfluxDB") == 0) {
+        tctx->format = KAFKA_FORMAT_INFLUXDB;
+
+      } else {
+        WARNING("write_kafka plugin: Invalid format string: %s", key);
+      }
+
+      sfree(key);
+
+    } else if (strcasecmp("StoreRates", child->key) == 0) {
+      status = cf_util_get_boolean(child, &tctx->store_rates);
+      (void)cf_util_get_flag(child, &tctx->graphite_flags,
+                             GRAPHITE_STORE_RATES);
+
+    } else if (strcasecmp("GraphiteSeparateInstances", child->key) == 0) {
+      status = cf_util_get_flag(child, &tctx->graphite_flags,
+                                GRAPHITE_SEPARATE_INSTANCES);
+
+    } else if (strcasecmp("GraphiteAlwaysAppendDS", child->key) == 0) {
+      status = cf_util_get_flag(child, &tctx->graphite_flags,
+                                GRAPHITE_ALWAYS_APPEND_DS);
+
+    } else if (strcasecmp("GraphitePreserveSeparator", child->key) == 0) {
+      status = cf_util_get_flag(child, &tctx->graphite_flags,
+                                GRAPHITE_PRESERVE_SEPARATOR);
+
+    } else if (strcasecmp("GraphiteUseTags", child->key) == 0) {
+      status =
+          cf_util_get_flag(child, &tctx->graphite_flags, GRAPHITE_USE_TAGS);
+
+    } else if (strcasecmp("GraphitePrefix", child->key) == 0) {
+      status = cf_util_get_string(child, &tctx->prefix);
+    } else if (strcasecmp("GraphitePostfix", child->key) == 0) {
+      status = cf_util_get_string(child, &tctx->postfix);
+    } else if (strcasecmp("GraphiteEscapeChar", child->key) == 0) {
+      char *tmp_buff = NULL;
+      status = cf_util_get_string(child, &tmp_buff);
+      if (strlen(tmp_buff) > 1)
+        WARNING(
+            "write_kafka plugin: The option \"GraphiteEscapeChar\" handles "
+            "only one character. Others will be ignored.");
+      tctx->escape_char = tmp_buff[0];
+      sfree(tmp_buff);
+    } else {
+      WARNING("write_kafka plugin: Invalid directive: %s.", child->key);
+    }
+
+    if (status != 0) break;
+  }
+
+  rd_kafka_topic_conf_set_partitioner_cb(tctx->conf, kafka_partition);
+  rd_kafka_topic_conf_set_opaque(tctx->conf, tctx);
+
+  ssnprintf(callback_name, sizeof(callback_name), "write_kafka/%s",
+            tctx->topic_name);
+
+  status = plugin_register_write(callback_name, kafka_write,
+                                 &(user_data_t){
+                                     .data = tctx,
+                                     .free_func = kafka_topic_context_free,
+                                 });
+  if (status != 0) {
+    WARNING(
+        "write_kafka plugin: plugin_register_write (\"%s\") "
+        "failed with status %i.",
+        callback_name, status);
+    goto errout;
+  }
+
+  pthread_mutex_init(&tctx->lock, /* attr = */ NULL);
+
+  return;
+errout:
+  if (tctx->topic_name != NULL) free(tctx->topic_name);
+  if (tctx->conf != NULL) rd_kafka_topic_conf_destroy(tctx->conf);
+  if (tctx->kafka_conf != NULL) rd_kafka_conf_destroy(tctx->kafka_conf);
+  sfree(tctx);
+} /* }}} int kafka_config_topic */
+
+static int kafka_config(oconfig_item_t *ci) /* {{{ */
+{
+  oconfig_item_t *child;
+  rd_kafka_conf_t *conf;
+  rd_kafka_conf_res_t ret;
+  char errbuf[1024];
+
+  if ((conf = rd_kafka_conf_new()) == NULL) {
+    WARNING("cannot allocate kafka configuration.");
+    return -1;
+  }
+  for (int i = 0; i < ci->children_num; i++) {
+    child = &ci->children[i];
+
+    if (strcasecmp("Topic", child->key) == 0) {
+      kafka_config_topic(conf, child);
+    } else if (strcasecmp(child->key, "Property") == 0) {
+      char *key = NULL;
+      char *val = NULL;
+
+      if (child->values_num != 2) {
+        WARNING("kafka properties need both a key and a value.");
+        goto errout;
+      }
+      if (child->values[0].type != OCONFIG_TYPE_STRING ||
+          child->values[1].type != OCONFIG_TYPE_STRING) {
+        WARNING("kafka properties needs string arguments.");
+        goto errout;
+      }
+      if ((key = strdup(child->values[0].value.string)) == NULL) {
+        WARNING("cannot allocate memory for attribute key.");
+        goto errout;
+      }
+      if ((val = strdup(child->values[1].value.string)) == NULL) {
+        WARNING("cannot allocate memory for attribute value.");
+        sfree(key);
+        goto errout;
+      }
+      ret = rd_kafka_conf_set(conf, key, val, errbuf, sizeof(errbuf));
+      if (ret != RD_KAFKA_CONF_OK) {
+        WARNING("cannot set kafka property %s to %s: %s", key, val, errbuf);
+        sfree(key);
+        sfree(val);
+        goto errout;
+      }
+      sfree(key);
+      sfree(val);
+    } else {
+      WARNING(
+          "write_kafka plugin: Ignoring unknown "
+          "configuration option \"%s\" at top level.",
+          child->key);
+    }
+  }
+  if (conf != NULL) rd_kafka_conf_destroy(conf);
+  return 0;
+errout:
+  if (conf != NULL) rd_kafka_conf_destroy(conf);
+  return -1;
+} /* }}} int kafka_config */
+
+void module_register(void) {
+  plugin_register_complex_config("write_kafka_line_protocol", kafka_config);
+}