vrl/stdlib/
set.rs

1use crate::compiler::prelude::*;
2use crate::path::{OwnedSegment, OwnedValuePath};
3
4fn set(path: Value, mut value: Value, data: Value) -> Resolved {
5    let path = match path {
6        Value::Array(segments) => {
7            let mut insert = OwnedValuePath::root();
8
9            for segment in segments {
10                let segment = match segment {
11                    Value::Bytes(path) => {
12                        OwnedSegment::Field(String::from_utf8_lossy(&path).into())
13                    }
14                    #[allow(clippy::cast_possible_truncation)] //TODO evaluate removal options
15                    Value::Integer(index) => OwnedSegment::Index(index as isize),
16                    value => {
17                        return Err(format!(
18                            "path segment must be either string or integer, not {}",
19                            value.kind()
20                        )
21                        .into());
22                    }
23                };
24
25                insert.push_segment(segment);
26            }
27
28            insert
29        }
30        value => {
31            return Err(ValueError::Expected {
32                got: value.kind(),
33                expected: Kind::array(Collection::any()) | Kind::bytes(),
34            }
35            .into());
36        }
37    };
38    value.insert(&path, data);
39    Ok(value)
40}
41
42#[derive(Clone, Copy, Debug)]
43pub struct Set;
44
45impl Function for Set {
46    fn identifier(&self) -> &'static str {
47        "set"
48    }
49
50    fn usage(&self) -> &'static str {
51        indoc! {"
52            Dynamically insert data into the path of a given object or array.
53
54            If you know the path you want to assign a value to,
55            use static path assignments such as `.foo.bar[1] = true` for
56            improved performance and readability. However, if you do not
57            know the path names, use the dynamic `set` function to
58            insert the data into the object or array.
59        "}
60    }
61
62    fn category(&self) -> &'static str {
63        Category::Path.as_ref()
64    }
65
66    fn internal_failure_reasons(&self) -> &'static [&'static str] {
67        &["The `path` segment must be a string or an integer."]
68    }
69
70    fn return_kind(&self) -> u16 {
71        kind::OBJECT | kind::ARRAY
72    }
73
74    fn parameters(&self) -> &'static [Parameter] {
75        const PARAMETERS: &[Parameter] = &[
76            Parameter::required(
77                "value",
78                kind::OBJECT | kind::ARRAY,
79                "The object or array to insert data into.",
80            ),
81            Parameter::required(
82                "path",
83                kind::ARRAY,
84                "An array of path segments to insert the value into.",
85            ),
86            Parameter::required("data", kind::ANY, "The data to be inserted."),
87        ];
88        PARAMETERS
89    }
90
91    fn examples(&self) -> &'static [Example] {
92        &[
93            example! {
94                title: "Single-segment top-level field",
95                source: r#"set!(value: { "foo": "bar" }, path: ["foo"], data: "baz")"#,
96                result: Ok(r#"{ "foo": "baz" }"#),
97            },
98            example! {
99                title: "Multi-segment nested field",
100                source: r#"set!(value: { "foo": { "bar": "baz" } }, path: ["foo", "bar"], data: "qux")"#,
101                result: Ok(r#"{ "foo": { "bar": "qux" } }"#),
102            },
103            example! {
104                title: "Array",
105                source: r#"set!(value: ["foo", "bar", "baz"], path: [-2], data: 42)"#,
106                result: Ok(r#"["foo", 42, "baz"]"#),
107            },
108            example! {
109                title: "Nested fields",
110                source: r#"set!(value: {}, path: ["foo", "bar"], data: "baz")"#,
111                result: Ok(r#"{ "foo": { "bar" : "baz" } }"#),
112            },
113            example! {
114                title: "Nested indexing",
115                source: r#"set!(value: {"foo": { "bar": [] }}, path: ["foo", "bar", 1], data: "baz")"#,
116                result: Ok(r#"{ "foo": { "bar": [null, "baz"] } }"#),
117            },
118            example! {
119                title: "External target",
120                source: r#"set!(value: ., path: ["bar"], data: "baz")"#,
121                input: r#"{ "foo": true }"#,
122                result: Ok(r#"{ "foo": true, "bar": "baz" }"#),
123            },
124            example! {
125                title: "Variable",
126                source: indoc! {r#"
127                    var = { "foo": true }
128                    set!(value: var, path: ["bar"], data: "baz")
129                "#},
130                result: Ok(r#"{ "foo": true, "bar": "baz" }"#),
131            },
132            example! {
133                title: "Invalid indexing",
134                source: r#"set!(value: [], path: ["foo"], data: "baz")"#,
135                result: Ok(r#"{ "foo": "baz" }"#),
136            },
137            example! {
138                title: "Invalid segment type",
139                source: r#"set!({"foo": { "bar": [92, 42] }}, ["foo", true], "baz")"#,
140                result: Err(
141                    r#"function call error for "set" at (0:56): path segment must be either string or integer, not boolean"#,
142                ),
143            },
144        ]
145    }
146
147    fn compile(
148        &self,
149        _state: &state::TypeState,
150        _ctx: &mut FunctionCompileContext,
151        arguments: ArgumentList,
152    ) -> Compiled {
153        let value = arguments.required("value");
154        let path = arguments.required("path");
155        let data = arguments.required("data");
156
157        Ok(SetFn { value, path, data }.as_expr())
158    }
159}
160
161#[derive(Debug, Clone)]
162pub(crate) struct SetFn {
163    value: Box<dyn Expression>,
164    path: Box<dyn Expression>,
165    data: Box<dyn Expression>,
166}
167
168impl FunctionExpression for SetFn {
169    fn resolve(&self, ctx: &mut Context) -> Resolved {
170        let path = self.path.resolve(ctx)?;
171        let value = self.value.resolve(ctx)?;
172        let data = self.data.resolve(ctx)?;
173
174        set(path, value, data)
175    }
176
177    fn type_def(&self, state: &state::TypeState) -> TypeDef {
178        let value_td = self.value.type_def(state);
179
180        let mut td = TypeDef::from(Kind::never()).fallible();
181
182        if value_td.is_array() {
183            td = td.or_array(Collection::any());
184        }
185
186        if value_td.is_object() {
187            td = td.or_object(Collection::any());
188        }
189
190        td
191    }
192}
193
194#[cfg(test)]
195mod tests {
196    use super::*;
197    use crate::value;
198
199    test_function![
200        set => Set;
201
202        array {
203            args: func_args![value: value!([]), path: vec![0], data: true],
204            want: Ok(vec![true]),
205            tdef: TypeDef::array(Collection::any()).fallible(),
206        }
207
208        object {
209            args: func_args![value: value!({}), path: vec!["foo"], data: true],
210            want: Ok(value!({ "foo": true })),
211            tdef: TypeDef::object(Collection::any()).fallible(),
212        }
213    ];
214}