text: /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
  
  /*  Fluent Bit
   *  ==========
   *  Copyright (C) 2019-2021 The Fluent Bit Authors
   *  Copyright (C) 2015-2018 Treasure Data Inc.
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  #include <fluent-bit/flb_output_plugin.h>
  #include <fluent-bit/flb_http_client.h>
  #include <fluent-bit/flb_pack.h>
  #include <fluent-bit/flb_utils.h>
  #include <fluent-bit/flb_time.h>
  #include <msgpack.h>
  
  #include "azure.h"
  #include "azure_conf.h"
  #include <mbedtls/base64.h>
  
  static int cb_azure_init(struct flb_output_instance *ins,
                            struct flb_config *config, void *data)
  {
      struct flb_azure *ctx;
  
      ctx = flb_azure_conf_create(ins, config);
      if (!ctx) {
          flb_plg_error(ins, "configuration failed");
          return -1;
      }
  
      flb_output_set_context(ins, ctx);
      return 0;
  }
  
  static int azure_format(const void *in_buf, size_t in_bytes,
                          char **out_buf, size_t *out_size,
                          struct flb_azure *ctx)
  {
      int i;
      int array_size = 0;
      int map_size;
      size_t off = 0;
      double t;
      struct flb_time tm;
      msgpack_unpacked result;
      msgpack_object root;
      msgpack_object *obj;
      msgpack_object map;
      msgpack_object k;
      msgpack_object v;
      msgpack_sbuffer mp_sbuf;
      msgpack_packer mp_pck;
      msgpack_sbuffer tmp_sbuf;
      msgpack_packer tmp_pck;
      flb_sds_t record;
  
      /* Count number of items */
      array_size = flb_mp_count(in_buf, in_bytes);
      msgpack_unpacked_init(&result);
  
      /* Create temporary msgpack buffer */
      msgpack_sbuffer_init(&mp_sbuf);
      msgpack_packer_init(&mp_pck, &mp_sbuf, msgpack_sbuffer_write);
      msgpack_pack_array(&mp_pck, array_size);
  
      off = 0;
      while (msgpack_unpack_next(&result, in_buf, in_bytes, &off) == MSGPACK_UNPACK_SUCCESS) {
          root = result.data;
  
          /* Get timestamp */
          flb_time_pop_from_msgpack(&tm, &result, &obj);
          t = flb_time_to_double(&tm);
  
          /* Create temporary msgpack buffer */
          msgpack_sbuffer_init(&tmp_sbuf);
          msgpack_packer_init(&tmp_pck, &tmp_sbuf, msgpack_sbuffer_write);
  
          map = root.via.array.ptr[1];
          map_size = map.via.map.size;
  
          msgpack_pack_map(&mp_pck, map_size + 1);
  
          /* Append the time key */
          msgpack_pack_str(&mp_pck, flb_sds_len(ctx->time_key));
          msgpack_pack_str_body(&mp_pck,
                                ctx->time_key,
                                flb_sds_len(ctx->time_key));
          msgpack_pack_double(&mp_pck, t);
  
          /* Append original map k/v */
          for (i = 0; i < map_size; i++) {
              k = map.via.map.ptr[i].key;
              v = map.via.map.ptr[i].val;
  
              msgpack_pack_object(&tmp_pck, k);
              msgpack_pack_object(&tmp_pck, v);
          }
          msgpack_sbuffer_write(&mp_sbuf, tmp_sbuf.data, tmp_sbuf.size);
          msgpack_sbuffer_destroy(&tmp_sbuf);
      }
  
      record = flb_msgpack_raw_to_json_sds(mp_sbuf.data, mp_sbuf.size);
      if (!record) {
          flb_errno();
          msgpack_sbuffer_destroy(&mp_sbuf);
          msgpack_unpacked_destroy(&result);
          return -1;
      }
  
      msgpack_sbuffer_destroy(&mp_sbuf);
      msgpack_unpacked_destroy(&result);
  
      *out_buf = record;
      *out_size = flb_sds_len(record);
  
      return 0;
  }
  
  static int build_headers(struct flb_http_client *c,
                           size_t content_length,
                           struct flb_azure *ctx)
  {
      int len;
      char *auth;
      char tmp[256];
      time_t t;
      size_t size;
      size_t olen;
      flb_sds_t rfc1123date;
      flb_sds_t str_hash;
      struct tm tm = {0};
      unsigned char hmac_hash[32] = {0};
      mbedtls_md_context_t mctx;
  
      /* Format Date */
      rfc1123date = flb_sds_create_size(32);
      if (!rfc1123date) {
          flb_errno();
          return -1;
      }
  
      t = time(NULL);
      if (!gmtime_r(&t, &tm)) {
          flb_errno();
          flb_sds_destroy(rfc1123date);
          return -1;
      }
      size = strftime(rfc1123date,
                      flb_sds_alloc(rfc1123date) - 1,
                      "%a, %d %b %Y %H:%M:%S GMT", &tm);
      if (size <= 0) {
          flb_errno();
          flb_sds_destroy(rfc1123date);
          return -1;
      }
      flb_sds_len_set(rfc1123date, size);
  
      /* Compose source string for the hash */
      str_hash = flb_sds_create_size(256);
      if (!str_hash) {
          flb_errno();
          flb_sds_destroy(rfc1123date);
          return -1;
      }
  
      len = snprintf(tmp, sizeof(tmp) - 1, "%zu\n", content_length);
      flb_sds_cat(str_hash, "POST\n", 5);
      flb_sds_cat(str_hash, tmp, len);
      flb_sds_cat(str_hash, "application/json\n", 17);
      flb_sds_cat(str_hash, "x-ms-date:", 10);
      flb_sds_cat(str_hash, rfc1123date, flb_sds_len(rfc1123date));
      flb_sds_cat(str_hash, "\n", 1);
      flb_sds_cat(str_hash, FLB_AZURE_RESOURCE, sizeof(FLB_AZURE_RESOURCE) - 1);
  
      /* Authorization signature */
      mbedtls_md_init(&mctx);
      mbedtls_md_setup(&mctx, mbedtls_md_info_from_type(MBEDTLS_MD_SHA256) , 1);
      mbedtls_md_hmac_starts(&mctx, (unsigned char *) ctx->dec_shared_key,
                             flb_sds_len(ctx->dec_shared_key));
      mbedtls_md_hmac_update(&mctx, (unsigned char *) str_hash,
                             flb_sds_len(str_hash));
      mbedtls_md_hmac_finish(&mctx, hmac_hash);
      mbedtls_md_free(&mctx);
  
      /* Encoded hash */
      mbedtls_base64_encode((unsigned char *) &tmp, sizeof(tmp) - 1, &olen,
                            hmac_hash, sizeof(hmac_hash));
      tmp[olen] = '\0';
  
      /* Append headers */
      flb_http_add_header(c, "User-Agent", 10, "Fluent-Bit", 10);
      flb_http_add_header(c, "Log-Type", 8,
                          ctx->log_type, flb_sds_len(ctx->log_type));
      flb_http_add_header(c, "Content-Type", 12, "application/json", 16);
      flb_http_add_header(c, "x-ms-date", 9, rfc1123date,
                          flb_sds_len(rfc1123date));
  
      size = 32 + flb_sds_len(ctx->customer_id) + olen;
      auth = flb_malloc(size);
      if (!auth) {
          flb_errno();
          flb_sds_destroy(rfc1123date);
          flb_sds_destroy(str_hash);
          return -1;
      }
  
  
      len = snprintf(auth, size, "SharedKey %s:%s",
                     ctx->customer_id, tmp);
      flb_http_add_header(c, "Authorization", 13, auth, len);
  
      /* release resources */
      flb_sds_destroy(rfc1123date);
      flb_sds_destroy(str_hash);
      flb_free(auth);
  
      return 0;
  }
  
  static void cb_azure_flush(const void *data, size_t bytes,
                             const char *tag, int tag_len,
                             struct flb_input_instance *i_ins,
                             void *out_context,
                             struct flb_config *config)
  {
      int ret;
      size_t b_sent;
      char *buf_data;
      size_t buf_size;
      struct flb_azure *ctx = out_context;
      struct flb_upstream_conn *u_conn;
      struct flb_http_client *c;
      flb_sds_t payload;
      (void) i_ins;
      (void) config;
  
      /* Get upstream connection */
      u_conn = flb_upstream_conn_get(ctx->u);
      if (!u_conn) {
          FLB_OUTPUT_RETURN(FLB_RETRY);
      }
  
      /* Convert binary logs into a JSON payload */
      ret = azure_format(data, bytes, &buf_data, &buf_size, ctx);
      if (ret == -1) {
          flb_upstream_conn_release(u_conn);
          FLB_OUTPUT_RETURN(FLB_ERROR);
      }
      payload = (flb_sds_t) buf_data;
  
      /* Compose HTTP Client request */
      c = flb_http_client(u_conn, FLB_HTTP_POST, ctx->uri,
                          buf_data, buf_size, NULL, 0, NULL, 0);
      flb_http_buffer_size(c, FLB_HTTP_DATA_SIZE_MAX);
  
      /* Append headers and Azure signature */
      ret = build_headers(c, flb_sds_len(payload), ctx);
      if (ret == -1) {
          flb_plg_error(ctx->ins, "error composing signature");
          flb_sds_destroy(payload);
          flb_http_client_destroy(c);
          flb_upstream_conn_release(u_conn);
          FLB_OUTPUT_RETURN(FLB_ERROR);
      }
  
      ret = flb_http_do(c, &b_sent);
      if (ret != 0) {
          flb_plg_warn(ctx->ins, "http_do=%i", ret);
          goto retry;
      }
      else {
          if (c->resp.status >= 200 && c->resp.status <= 299) {
              flb_plg_info(ctx->ins, "customer_id=%s, HTTP status=%i",
                           ctx->customer_id, c->resp.status);
          }
          else {
              if (c->resp.payload_size > 0) {
                  flb_plg_warn(ctx->ins, "http_status=%i:\n%s",
                               c->resp.status, c->resp.payload);
              }
              else {
                  flb_plg_warn(ctx->ins, "http_status=%i", c->resp.status);
              }
              goto retry;
          }
      }
  
      /* Cleanup */
      flb_http_client_destroy(c);
      flb_sds_destroy(payload);
      flb_upstream_conn_release(u_conn);
      FLB_OUTPUT_RETURN(FLB_OK);
  
      /* Issue a retry */
   retry:
      flb_http_client_destroy(c);
      flb_sds_destroy(payload);
      flb_upstream_conn_release(u_conn);
      FLB_OUTPUT_RETURN(FLB_RETRY);
  }
  
  static int cb_azure_exit(void *data, struct flb_config *config)
  {
      struct flb_azure *ctx = data;
  
      flb_azure_conf_destroy(ctx);
      return 0;
  }
  
  struct flb_output_plugin out_azure_plugin = {
      .name         = "azure",
      .description  = "Send events to Azure HTTP Event Collector",
      .cb_init      = cb_azure_init,
      .cb_flush     = cb_azure_flush,
      .cb_exit      = cb_azure_exit,
  
      /* Plugin flags */
      .flags          = FLB_OUTPUT_NET | FLB_IO_TLS,
  };
  