gearbox 3.0.0

Excessive tooling for Rust, boosting productivity and operations
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
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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278

use crate::log::fmt::formatter::LogFormatter;
use crate::log::fmt::log_layer::{LogLayer, Type};
use crate::log::fmt::log_value::LogValue;
use crate::log::fmt::storage::Storage;
use crate::time::{DateTime, SecondsFormat};
use hashbrown::HashMap;
use serde::ser::{SerializeMap, Serializer};
use tracing::{Event, Id, Level, Subscriber};
use tracing_subscriber::fmt::MakeWriter;
use tracing_subscriber::registry::{LookupSpan, SpanRef};

/// Keys for core fields of the Bunyan format (https://github.com/trentm/node-bunyan#core-fields)
const BUNYAN_VERSION: &str = "v";
const LEVEL: &str = "level";
const NAME: &str = "name";
const HOSTNAME: &str = "hostname";
const PID: &str = "pid";
const TIME: &str = "time";
const MESSAGE: &str = "msg";
const _SOURCE: &str = "src";

const BUNYAN_RESERVED_FIELDS: [&str; 7] =
    [BUNYAN_VERSION, LEVEL, NAME, HOSTNAME, PID, TIME, MESSAGE];

/// Convert from log levels to Bunyan's levels.
fn to_bunyan_level(level: &tracing::Level) -> u16 {
    match *level {
        tracing::Level::ERROR => 50,
        tracing::Level::WARN => 40,
        tracing::Level::INFO => 30,
        tracing::Level::DEBUG => 20,
        tracing::Level::TRACE => 10,
    }
}

/// This layer is exclusively concerned with formatting information using the [Bunyan format](https://github.com/trentm/node-bunyan).
/// It relies on the upstream `JsonStorageLayer` to get access to the fields attached to
/// each span.
pub struct Bunyan {
    pid: u32,
    hostname: String,
    bunyan_version: u8,
    name: String,
    default_fields: HashMap<String, LogValue>,
}

impl Bunyan {
    /// Create a new `BunyanFormattingLayer`.

    pub fn new(name: String) -> Self {
        Self::with_default_fields(name, HashMap::new())
    }

    pub fn with_default_fields(name: String, default_fields: HashMap<String, LogValue>) -> Self {
        Self {
            name,
            pid: crate::common::process::id(),
            hostname: crate::net::hostname::gethostname()
                .to_string_lossy()
                .into_owned(),
            bunyan_version: 0,
            default_fields,
        }
    }

    fn serialize_bunyan_core_fields(
        &self,
        map_serializer: &mut impl SerializeMap<Error = serde_json::Error>,
        message: &str,
        level: &Level,
    ) -> Result<(), std::io::Error> {
        map_serializer.serialize_entry(BUNYAN_VERSION, &self.bunyan_version)?;
        map_serializer.serialize_entry(NAME, &self.name)?;
        map_serializer.serialize_entry(MESSAGE, &message)?;
        map_serializer.serialize_entry(LEVEL, &to_bunyan_level(level))?;
        map_serializer.serialize_entry(HOSTNAME, &self.hostname)?;
        map_serializer.serialize_entry(PID, &self.pid)?;
        map_serializer.serialize_entry(
            TIME,
            &DateTime::now_or_zero().to_rfc3339_opts(SecondsFormat::Millis, true),
        )?;
        Ok(())
    }

    /// Given a span, it serialised it to a in-memory buffer (vector of bytes).
    fn serialize_span<S: Subscriber + for<'a> tracing_subscriber::registry::LookupSpan<'a>>(
        &self,
        span: &SpanRef<S>,
        ty: Type,
    ) -> Result<Vec<u8>, std::io::Error> {
        let mut buffer = Vec::new();
        let mut serializer = serde_json::Serializer::new(&mut buffer);
        let mut map_serializer = serializer.serialize_map(None)?;
        let message = format_span_context(span, ty);
        self.serialize_bunyan_core_fields(&mut map_serializer, &message, span.metadata().level())?;
        // Additional metadata useful for debugging
        // They should be nested under `src` (see https://github.com/trentm/node-bunyan#src )
        // but `tracing` does not support nested values yet
        map_serializer.serialize_entry("target", span.metadata().target())?;
        map_serializer.serialize_entry("line", &span.metadata().line())?;
        map_serializer.serialize_entry("file", &span.metadata().file())?;

        // Add all default fields
        for (key, value) in self.default_fields.iter() {
            if !BUNYAN_RESERVED_FIELDS.contains(&key.as_str()) {
                map_serializer.serialize_entry(key, &serde_json::Value::from(value))?;
            } else {
                tracing::debug!(
                    "{} is a reserved field in the bunyan log format. Skipping it.",
                    key
                );
            }
        }

        let extensions = span.extensions();
        if let Some(visitor) = extensions.get::<Storage>() {
            for (key, value) in visitor.values() {
                if !BUNYAN_RESERVED_FIELDS.contains(key) {
                    map_serializer.serialize_entry(key, &serde_json::Value::from(value))?;
                } else {
                    tracing::debug!(
                        "{} is a reserved field in the bunyan log format. Skipping it.",
                        key
                    );
                }
            }
        }
        map_serializer.end()?;
        Ok(buffer)
    }
}

impl Default for Bunyan {
    fn default() -> Self {
        Self {
            pid: 0,
            hostname: "".to_string(),
            bunyan_version: 0,
            name: "".to_string(),
            default_fields: Default::default(),
        }
    }
}

/// Ensure consistent formatting of the span context.
///
/// Example: "[AN_INTERESTING_SPAN - START]"
fn format_span_context<S: Subscriber + for<'a> tracing_subscriber::registry::LookupSpan<'a>>(
    span: &SpanRef<S>,
    ty: Type,
) -> String {
    format!("[{} - {}]", span.metadata().name().to_uppercase(), ty)
}

/// Ensure consistent formatting of event message.
///
/// Examples:
/// - "[AN_INTERESTING_SPAN - EVENT] My event message" (for an event with a parent span)
/// - "My event message" (for an event without a parent span)
fn format_event_message<S: Subscriber + for<'a> tracing_subscriber::registry::LookupSpan<'a>>(
    current_span: &Option<SpanRef<S>>,
    event: &Event,
    event_visitor: &Storage<'_>,
) -> String {
    // Extract the "message" field, if provided. Fallback to the target, if missing.
    let mut message = event_visitor
        .values()
        .get("message")
        .map(|v| match v {
            LogValue::String(s) => Some(s.as_str()),
            _ => None,
        })
        .flatten()
        .unwrap_or_else(|| event.metadata().target())
        .to_owned();

    // If the event is in the context of a span, prepend the span name to the message.
    if let Some(span) = &current_span {
        message = format!("{} {}", format_span_context(span, Type::Event), message);
    }

    message
}

impl LogFormatter for Bunyan {
    fn from_log_layer<W: for<'a> MakeWriter<'a> + 'static, F: LogFormatter + Default>(
        layer: &LogLayer<W, F>,
    ) -> Self {
        Self {
            pid: layer.proc_id().clone().unwrap_or(0),
            hostname: layer.hostname().clone().unwrap_or("localhost".to_string()),
            bunyan_version: 0,
            name: layer.application().clone().unwrap_or("app".to_string()),
            default_fields: Default::default(),
        }
    }

    fn format_event<S: Subscriber + for<'a> LookupSpan<'a>>(
        &mut self,
        current_span: &Option<SpanRef<S>>,
        event: &Event,
        event_visitor: &Storage<'_>,
    ) -> String {
        let mut event_visitor = Storage::default();
        event.record(&mut event_visitor);

        // Opting for a closure to use the ? operator and get more linear code.
        let format = || {
            let mut buffer = Vec::new();

            let mut serializer = serde_json::Serializer::new(&mut buffer);
            let mut map_serializer = serializer.serialize_map(None)?;

            let message = format_event_message(&current_span, event, &event_visitor);
            self.serialize_bunyan_core_fields(
                &mut map_serializer,
                &message,
                event.metadata().level(),
            )?;
            // Additional metadata useful for debugging
            // They should be nested under `src` (see https://github.com/trentm/node-bunyan#src )
            // but `tracing` does not support nested values yet
            map_serializer.serialize_entry("target", event.metadata().target())?;
            map_serializer.serialize_entry("line", &event.metadata().line())?;
            map_serializer.serialize_entry("file", &event.metadata().file())?;

            // Add all default fields
            for (key, value) in self.default_fields.iter().filter(|(key, _)| {
                key.as_str() != "message" && !BUNYAN_RESERVED_FIELDS.contains(&key.as_str())
            }) {
                map_serializer.serialize_entry(key, &serde_json::Value::from(value))?;
            }

            // Add all the other fields associated with the event, expect the message we already used.
            for (key, value) in event_visitor
                .values()
                .iter()
                .filter(|(&key, _)| key != "message" && !BUNYAN_RESERVED_FIELDS.contains(&key))
            {
                map_serializer.serialize_entry(key, &serde_json::Value::from(value))?;
            }

            // Add all the fields from the current span, if we have one.
            if let Some(span) = &current_span {
                let extensions = span.extensions();
                if let Some(visitor) = extensions.get::<Storage>() {
                    for (key, value) in visitor.values() {
                        if !BUNYAN_RESERVED_FIELDS.contains(key) {
                            map_serializer.serialize_entry(key, &serde_json::Value::from(value))?;
                        } else {
                            tracing::debug!(
                                "{} is a reserved field in the bunyan log format. Skipping it.",
                                key
                            );
                        }
                    }
                }
            }
            map_serializer.end()?;
            Ok(buffer)
        };
        format()
            .map_err(|e: std::io::Error| e.to_string())
            .and_then(|t| String::from_utf8(t).map_err(|e| e.to_string()))
            .unwrap_or_else(|e| e)
    }

    fn format_span<S: Subscriber + for<'a> LookupSpan<'a>>(
        &mut self,
        span: &SpanRef<S>,
        ty: Type,
    ) -> String {
        self.serialize_span(&span, ty)
            .map_err(|e: std::io::Error| e.to_string())
            .and_then(|t| String::from_utf8(t).map_err(|e| e.to_string()))
            .unwrap_or_else(|e| e)
    }
}