fiddler 4.9.1

Data Stream processor written in rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105

use crate::config::register_plugin;
use crate::config::{parse_configuration_item, Item, ItemType};
use crate::config::{ConfigSpec, ExecutionType};
use crate::Message;
use crate::{Closer, Error, Output};
use async_trait::async_trait;
use fiddler_macros::fiddler_registration_func;
use serde::{Deserialize, Serialize};
use serde_yaml::Value;

#[derive(Deserialize, Serialize)]
struct CheckConfig {
    label: Option<String>,
    condition: String,
    output: Item,
}

pub struct Check {
    condition: String,
    output: Box<dyn Output + Send + Sync>,
}

fn perform_check(condition: &str, json_str: String) -> Result<(), Error> {
    let mut runtime = jmespath::Runtime::new();
    runtime.register_builtin_functions();
    let expr = runtime
        .compile(condition)
        .map_err(|e| Error::ProcessingError(format!("{e}")))?;
    let data = jmespath::Variable::from_json(&json_str)
        .map_err(|e| Error::ProcessingError(format!("{e}")))?;

    let result = expr
        .search(data)
        .map_err(|e| Error::ProcessingError(format!("{e}")))?;

    // Explicitly check that result is a boolean type
    match result.as_boolean() {
        Some(true) => Ok(()),
        Some(false) => Err(Error::ConditionalCheckfailed),
        None => Err(Error::ProcessingError(format!(
            "Condition '{}' did not return a boolean value, got: {:?}",
            condition, result
        ))),
    }
}

#[async_trait]
impl Output for Check {
    async fn write(&mut self, message: Message) -> Result<(), Error> {
        let json_str = String::from_utf8(message.bytes.clone())
            .map_err(|e| Error::ProcessingError(format!("{e}")))?;

        perform_check(&self.condition, json_str)?;

        self.output.write(message).await?;
        Ok(())
    }
}

#[async_trait]
impl Closer for Check {
    async fn close(&mut self) -> Result<(), Error> {
        self.output.close().await
    }
}

#[fiddler_registration_func]
fn create_check(conf: Value) -> Result<ExecutionType, Error> {
    let c: CheckConfig = serde_yaml::from_value(conf.clone())?;
    let _ = jmespath::compile(&c.condition)
        .map_err(|e| Error::ConfigFailedValidation(format!("{e}")))?;

    let ri = parse_configuration_item(ItemType::Output, &c.output.extra).await?;

    let step = ((ri.creator)(ri.config.clone())).await?;
    let out = match step {
        ExecutionType::Output(o) => o,
        _ => {
            return Err(Error::ConfigFailedValidation(
                "output must be a valid output".into(),
            ))
        }
    };

    let s = Check {
        condition: c.condition,
        output: out,
    };

    Ok(ExecutionType::Output(Box::new(s)))
}

pub(super) fn register_check() -> Result<(), Error> {
    let config = "type: object
properties:
  label:
    type: string
  condition:
    type: string
  output:
    type: object";
    let conf_spec = ConfigSpec::from_schema(config)?;

    register_plugin("check".into(), ItemType::Output, conf_spec, create_check)
}