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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

use crate::google::LogSeverity;
use inflector::Inflector;
use serde::ser::SerializeMap;
use std::{collections::BTreeMap, fmt};
use tracing_core::Field;
use tracing_subscriber::field::{Visit, VisitOutput};

/// Visitor for Stackdriver events that formats custom fields
pub(crate) struct Visitor<'a, S>
where
    S: SerializeMap,
{
    values: BTreeMap<&'a str, serde_json::Value>,
    severity: LogSeverity,
    serializer: S,
}

impl<'a, S> Visitor<'a, S>
where
    S: SerializeMap,
{
    /// Returns a new default visitor using the provided writer
    pub(crate) fn new(severity: LogSeverity, serializer: S) -> Self {
        Self {
            values: BTreeMap::new(),
            severity,
            serializer,
        }
    }
}

impl<'a, S> VisitOutput<fmt::Result> for Visitor<'a, S>
where
    S: SerializeMap,
{
    fn finish(mut self) -> fmt::Result {
        let inner = || {
            let severity = self
                .values
                .remove("severity")
                .map(LogSeverity::from)
                .unwrap_or(self.severity);

            self.serializer.serialize_entry("severity", &severity)?;

            let mut http_request = BTreeMap::new();
            let mut labels = BTreeMap::new();

            for (key, value) in self.values {
                let mut key_segments = key.splitn(2, '.');

                match (key_segments.next(), key_segments.next()) {
                    (Some("http_request"), Some(request_key)) => {
                        http_request.insert(request_key.to_camel_case(), value);
                    }
                    (Some("labels"), Some(label_key)) => {
                        let value = match value {
                            serde_json::Value::String(value) => value,
                            _ => value.to_string(),
                        };

                        labels.insert(label_key.to_camel_case(), value);
                    }
                    (Some("insert_id"), None) => {
                        let value = match value {
                            serde_json::Value::String(value) => value,
                            _ => value.to_string(),
                        };

                        self.serializer
                            .serialize_entry("logging.googleapis.com/insertId", &value)?;
                    }
                    (Some(key), None) => self
                        .serializer
                        .serialize_entry(&key.to_camel_case(), &value)?,
                    _ => self
                        .serializer
                        .serialize_entry(&key.to_camel_case(), &value)?,
                }
            }

            if !http_request.is_empty() {
                self.serializer
                    .serialize_entry("httpRequest", &http_request)?;
            }

            if !labels.is_empty() {
                self.serializer
                    .serialize_entry("logging.googleapis.com/labels", &labels)?;
            }

            self.serializer.end()
        };

        if inner().is_err() {
            Err(fmt::Error)
        } else {
            Ok(())
        }
    }
}

impl<'a, S> Visit for Visitor<'a, S>
where
    S: SerializeMap,
{
    fn record_i64(&mut self, field: &Field, value: i64) {
        self.values
            .insert(field.name(), serde_json::Value::from(value));
    }

    fn record_u64(&mut self, field: &Field, value: u64) {
        self.values
            .insert(field.name(), serde_json::Value::from(value));
    }

    fn record_bool(&mut self, field: &Field, value: bool) {
        self.values
            .insert(field.name(), serde_json::Value::from(value));
    }

    fn record_str(&mut self, field: &Field, value: &str) {
        self.values
            .insert(field.name(), serde_json::Value::from(value));
    }

    fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
        self.values.insert(
            field.name(),
            serde_json::Value::from(format!("{:?}", value)),
        );
    }

    #[cfg(all(tracing_unstable, feature = "valuable"))]
    fn record_value(&mut self, field: &Field, value: valuable::Value<'_>) {
        let value = serde_json::to_value(valuable_serde::Serializable::new(value)).unwrap();

        self.values.insert(field.name(), value);
    }
}

impl<'a, S> fmt::Debug for Visitor<'a, S>
where
    S: SerializeMap,
{
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter
            .debug_struct("Visitor")
            .field("values", &self.values)
            .finish()
    }
}