Simple Log Service:Syntaxe JMESPath

JMESPath est un langage de requête et de calcul amélioré pour le format JSON. Utilisez JMESPath pour extraire, calculer et convertir des données JSON. Pour plus d'informations, consultez le Tutoriel JMESPath.

json_select(value, "jmes_expression", ...)
e_json(field_name, jmes="jmes_expression", ...)
e_split(field_name, ... jmes="jmes_expression", ...)

Obtenir une valeur à l'aide de la clé d'un champ

• Journal brut

  json_data: {"a":"foo","b":"bar","c":"baz"}

• Syntaxe de transformation

  # Get the value of a from the JSON expression.
  e_set("a1", json_select(v("json_data"), "a"))
  # Get the value of b from the JSON expression.
  e_set("b1", json_select(v("json_data"), "b"))
  # Get the value of c from the JSON expression.
  e_set("c1", json_select(v("json_data"), "c"))

• Résultat

  a1:foo
  b1:bar
  c1:baz
  json_data:{"a":"foo","b":"bar","c":"baz"}

Obtenir une valeur imbriquée

• Journal brut

  json_data:{"a": {"b":{"c":{"d":"value"}}}}

• Syntaxe de transformation

  # Get the value of d from the JSON expression.
  e_set("e", json_select(v("json_data"), "a.b.c.d"))

• Résultat

  e:value
  json_data:{"a": {"b":{"c":{"d":"value"}}}}

Obtenir une valeur par découpage des données

• Journal brut

  json_data:{"a": ["b", "c", "d", "e", "f"]}

• Syntaxe de transformation

  # Get the values from field a, starting from slice 2. The value at slice 0 is b, and the value at slice 1 is c.
  e_set("key", json_select(v("json_data"), "a[2:]"))

• Résultat

  json_data:{"a": ["b", "c", "d", "e", "f"]}
  key:["d", "e", "f"]

Utilisation combinée

• Journal brut

  json_data:{"a": {"b": {"c": [{"d": [0, [1, 2]]}, {"d": [3, 4]}]}}}

• Syntaxe de transformation

  # c[0] represents the {"d": [0, [1, 2]]} part. d[1] represents [1, 2]]. The return value is 1.
  e_set("key", json_select(v("json_data"), "a.b.c[0].d[1][0]"))

• Résultat

  json_data:{"a": {"b": {"c": [{"d": [0, [1, 2]]}, {"d": [3, 4]}]}}}
  key:1

Obtenir une valeur à l'aide d'une projection

• Exemple 1

  • Journal brut

    json_data:{"people": [{"first": "James", "last": "d"},{"first": "Jacob", "last": "e"},{"first": "Jayden", "last": "f"},{"missing": "different"}],"foo": {"bar": "baz"}}

  • Syntaxe de transformation

    # Get the values of the first fields from the people list.
    e_set("key", json_select(v("json_data"), "people[*].first"))

  • Résultat

    json_data:{"people": [{"first": "James", "last": "d"},{"first": "Jacob", "last": "e"},{"first": "Jayden", "last": "f"},{"missing": "different"}],"foo": {"bar": "baz"}}
    key:["James", "Jacob", "Jayden"]

• Exemple 2

  • Journal brut

    json_data:{"ops": {"functionA": {"numArgs": 2},"functionB": {"numArgs": 3},"functionC": {"variadic": true}}}

  • Syntaxe de transformation

    # Get the values of the numArgs fields from ops.
    e_set("key", json_select(v("json_data"), "ops.*.numArgs"))

  • Résultat

    json_data:{"ops": {"functionA": {"numArgs": 2},"functionB": {"numArgs": 3},"functionC": {"variadic": true}}}
    key:[2, 3]

• Exemple 3

  • Journal brut

    json_data:{"machines": [{"name": "a", "state": "running"},{"name": "b", "state": "stopped"},{"name": "c", "state": "running"}]}

  • Syntaxe de transformation

    # Get the name values from machines where the state is 'running'.
    e_set("key", json_select(v("json_data"), "machines[?state=='running'].name"))

  • Résultat

    json_data:{"machines": [{"name": "a", "state": "running"},{"name": "b", "state": "stopped"},{"name": "c", "state": "running"}]}
    key:["a", "c"]

Extraire plusieurs valeurs

• Journal brut

  json_data:{"people": [{"name": "a","state": {"name": "up"}},{"name": "b","state": {"name": "down"}}]}

• Syntaxe de transformation

  # Get the name and state values from people.
  e_set("key", json_select(v("json_data"), "people[].[name, state.name]"))

• Résultat

  json_data:{"people": [{"name": "a","state": {"name": "up"}},{"name": "b","state": {"name": "down"}}]}
  key:[["a", "up"], ["b", "down"]]

Calculer le nombre d'éléments dans un tableau

• Journal brut

  json_data:{"a": ["b", "c", "d", "e", "f"]}

• Syntaxe

  # Get the length of array a.
  e_set("key", json_select(v("json_data"), "length(a)"))

  # Get the length of array a. If length(a) > 0, set the no-empty field to true.
  e_if(json_select(v("json_data"), "length(a)", default=0), e_set("no-empty", true))

  Résultat

  json_data:{"a": ["b", "c", "d", "e", "f"]}
  key:5

  json_data:{"a": ["b", "c", "d", "e", "f"]}
  no-empty:true