Telegraf 1.32.3输出ClickHouse：test_data字段类型转换失败求助

在Alpine系统上使用Telegraf 1.32.3，通过StatsD输入将数据输出至ClickHouse。示例输入消息如下：

globals_properties_count,app_name=SAGA_LOCAL_TEST,metric_type=counter,name=foo,service=web_cluster,test_data=true value=1i 1735736040000000000

遇到的问题：无法将布尔类型的tag字段test_data转换为ClickHouse的UInt8类型，该字段始终以String类型存储。已配置outputs.sql.convert但未生效，相关配置片段：

[outputs.sql.convert]
conversion_style     = "literal"
integer              = "Int64"
text                 = "String"
timestamp            = "DateTime"
defaultvalue         = "String"
unsigned             = "UInt64"
bool                 = "UInt8"
real                 = "Float64"

当前ClickHouse建表语句（test_data为String类型）：

CREATE TABLE default.globals_properties_count
(
    `timestamp` DateTime,
    `app_name` String,
    `metric_type` String,
    `name` String,
    `service` String,
    `test_data` String,
    `value` Int64
)
ENGINE = MergeTree
PARTITION BY toYYYYMMDD(timestamp)
ORDER BY timestamp
SETTINGS index_granularity = 8192

完整Telegraf配置如下：

[[processors.printer]] ##Enable for verbose logging

[global_tags]
  app_name = "$APP_NAME"
  service = "$SERVICE"

[agent]
  omit_hostname = true
  debug = true
  ## Log only error level messages.
  quiet = false
  metric_buffer_limit = 10000

[[inputs.mem]]

[[inputs.cpu]]
  ## Whether to report per-cpu stats or not
  percpu = false
  ## Whether to report total system cpu stats or not
  totalcpu = true
  ## If true, collect raw CPU time metrics.
  collect_cpu_time = false
  ## If true, compute and report the sum of all non-idle CPU states.
  report_active = true

# Statsd Server
[[inputs.statsd]]
   ## Address and port to host UDP listener on
   service_address = ":8125"

   ## The following configuration options control when telegraf clears it's cache
   ## of previous values. If set to false, then telegraf will only clear it's
   ## cache when the daemon is restarted.
   ## Reset gauges every interval (default=true)
   delete_gauges = true
   ## Reset counters every interval (default=true)
   delete_counters = true
   ## Reset sets every interval (default=true)
   delete_sets = true
   ## Reset timings & histograms every interval (default=true)
   delete_timings = true

   ## Percentiles to calculate for timing & histogram stats
   percentiles = [90]

   ## separator to use between elements of a statsd metric
   metric_separator = "_"


   ## Number of UDP messages allowed to queue up, once filled,
   ## the statsd server will start dropping packets
   allowed_pending_messages = 10000

   ## Number of timing/histogram values to track per-measurement in the
   ## calculation of percentiles. Raising this limit increases the accuracy
   ## of percentiles but also increases the memory usage and cpu time.
   percentile_limit = 1000

   fieldexclude = ["metric_type"]


[[outputs.sql]]
   driver = "clickhouse"
   data_source_name = "tcp://clickhouse:9000?database=default"
   timestamp_column = "timestamp"
   table_template = "CREATE TABLE IF NOT EXISTS {TABLE}({COLUMNS}) ENGINE = MergeTree()  ORDER by (timestamp)  Partition by toYYYYMMDD(timestamp)"
   table_exists_template = "SELECT 1 FROM {TABLE} LIMIT 1"

  [outputs.sql.convert]
    conversion_style     = "literal"
    integer              = "Int64"
    text                 = "String"
    timestamp            = "DateTime"
    defaultvalue         = "String"
    unsigned             = "UInt64"
    bool                 = "UInt8"
    real                 = "Float64"

问题根源：Telegraf的outputs.sql.convert仅对字段（field）生效，而test_data是标签（tag），标签默认会被当作String类型处理，不会触发该转换规则。

解决步骤：

1. 修改ClickHouse表结构 #

将test_data字段类型改为UInt8：

ALTER TABLE default.globals_properties_count MODIFY COLUMN test_data UInt8;

2. 添加Telegraf处理器转换标签类型 #

在Telegraf配置中，[[inputs.statsd]]之后、[[outputs.sql]]之前添加以下处理器，先把标签转为字段，再将布尔值转为UInt8：

[[processors.tags_to_fields]]
  keys = ["test_data"]

[[processors.converter]]
  [processors.converter.fields]
    uint8 = ["test_data"]

3. 可选：清理冗余标签 #

如果不需要test_data作为标签保留，可在[[inputs.statsd]]中添加配置排除该标签：

[[inputs.statsd]]
  # 原有配置...
  tagexclude = ["test_data"]

4. 重启Telegraf服务 #

使配置生效：

telegraf restart

验证：发送示例消息后查询ClickHouse表，test_data字段应显示为1（对应true）或0（对应false）的UInt8值。

内容的提问来源于stack exchange，提问作者Stan Wiechers