parsing - Clojure - 解析 Elasticsearch 查询响应并提取值

Question

我正在解析 Elasticsearch 查询响应并将其转换为我自己的格式。响应可能具有嵌套桶，并且嵌套级别对于每个查询都是可变的。这是结果的简化版本:

{:bucket-aggregation
 {:buckets
  [{:key "outer_bucket"
    :bucket-aggregation
    {:buckets
     [{:key "inner_bucket_1"
       :bucket-aggregation
       {:buckets
        [{:key 1510657200000, :sum {:value 25}}
         {:key 1510660800000, :sum {:value 50}}]}}
      {:key "inner_bucket_2"
       :bucket-aggregation
       {:buckets
        [{:key 1510657200000, :sum {:value 30}}
         {:key 1510660800000, :sum {:value 35}}]}}
      {:key "inner_bucket_3"
       :bucket-aggregation
       {:buckets
        [{:key 1510657200000, :sum {:value 40}}
         {:key 1510660800000, :sum {:value 45}}]}}]}}]}}

我想将 :value 和 :key 提取到如下结构中:

[{:key ["outer_bucket" "inner_bucket_1" 1510657200000], :value 25}
 {:key ["outer_bucket" "inner_bucket_1" 1510660800000], :value 50}
 {:key ["outer_bucket" "inner_bucket_2" 1510657200000], :value 30}
 {:key ["outer_bucket" "inner_bucket_2" 1510660800000], :value 35}
 {:key ["outer_bucket" "inner_bucket_3" 1510657200000], :value 40}
 {:key ["outer_bucket" "inner_bucket_3" 1510660800000], :value 45}]

关于我应该如何解决这个问题有什么建议吗？

编辑:简化所需的格式

Answer 1

这是使用 clojure.walk/postwalk 执行此操作的另一种方法它不假设固定的嵌套深度，即它可以处理更浅或更深的嵌套输入。

(clojure.walk/postwalk
  (fn [v]
    (cond
      ;; deepest case, pull up sum value
      (and (map? v) (:key v) (:sum v))
      {:key [(:key v)], :value (get-in v [:sum :value])}
      ;; pull up unnecessary buckets map wrapper
      (and (map? v) (:buckets v))
      (flatten (:buckets v))
      ;; select outer bucket + inner buckets
      (and (map? v) (:key v) (:bucket-aggregation v))
      (let [outer-key (:key v)
            buckets (:bucket-aggregation v)]
        (map #(update % :key (fn [k] (into [outer-key] k))) buckets))
      ;; pass-through
      :else v))
  (:bucket-aggregation result))
=>
({:key ["outer_bucket" "inner_bucket_1" 1510657200000], :value 25}
 {:key ["outer_bucket" "inner_bucket_1" 1510660800000], :value 50}
 {:key ["outer_bucket" "inner_bucket_2" 1510657200000], :value 30}
 {:key ["outer_bucket" "inner_bucket_2" 1510660800000], :value 35}
 {:key ["outer_bucket" "inner_bucket_3" 1510657200000], :value 40}
 {:key ["outer_bucket" "inner_bucket_3" 1510660800000], :value 45})