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https://github.com/dburriss/fennel
A Prometheus parsing and line generation library
https://github.com/dburriss/fennel
domain-telemetry parser prometheus team-devon
Last synced: 21 days ago
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A Prometheus parsing and line generation library
- Host: GitHub
- URL: https://github.com/dburriss/fennel
- Owner: dburriss
- License: mit
- Created: 2020-05-31T13:50:21.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-10-15T12:06:40.000Z (about 1 year ago)
- Last Synced: 2024-11-10T10:51:56.243Z (about 1 month ago)
- Topics: domain-telemetry, parser, prometheus, team-devon
- Language: F#
- Homepage:
- Size: 36.1 KB
- Stars: 14
- Watchers: 4
- Forks: 2
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Fennel
*Fennel* - **A flowering plant in the carrot family**
Fennel is a simple library that speaks Promethean. If can translate prometheus log strings to typed metrics, as well as create metrics in well formatted Prometheus lines.
## Why Fennel?
> But the noble son of Iapetus outwitted him and stole the far-seen gleam of unwearying fire in a hollow fennel stalk - Hesiod in the Theogony
The myth has it that Prometheus stole fire from Zeus by smuggling an ember in a hollow fennel stalk.
If you are wondering more about why I created this than about the name, it is simple. I was looking for something that just allowed me to create Prometheus log lines as strings.
I also wanted to be able to parse Prometheus logs. Circa 2019 when I looked for this all I found were libraries that tied very deeply into ASP.NET Core.
I had been looking for an excuse to play with a parsing library like FParsec... and here we are.
## Nuget
Available on [Nuget.org](https://www.nuget.org/packages/Fennel/)
### Nuget Package Manger
`Install-Package Fennel`
### .NET CLI
`dotnet add package Fennel`
### PackageReference
``
### Paket
`paket add Fennel`
## Usage
### Translating text to Types
Assuming we have the following Prometheus logs as `input`:
```text
# Finally a summary, which has a complex representation, too:
# HELP rpc_duration_seconds A summary of the RPC duration in seconds.
# TYPE rpc_duration_seconds summary
rpc_duration_seconds{quantile="0.01"} 3102
rpc_duration_seconds{quantile="0.05"} 3272
rpc_duration_seconds{quantile="0.5"} 4773
rpc_duration_seconds{quantile="0.9"} 9001
rpc_duration_seconds{quantile="0.99"} 76656
rpc_duration_seconds_sum 1.7560473e+07
rpc_duration_seconds_count 2693
```
You can break the result down into individually parsed lines.
#### F#
```f#
open Fennel
let lines = Prometheus.parseText input
```
Each line has multiple possibilities:
```f#
match line with
| Help (name, doc) -> printfn "Help line %A" (name, doc)
| Comment txt -> printfn "Comment line %s" txt
| Type (name, t) -> printfn "Type line %A" (name, t)
| Metric m -> printfn "Metric line %A" m
| Blank -> printfn "Blank line"
```
#### C#
```c#
using Fennel.CSharp;
var lines = Prometheus.ParseText(input);
```
Or you can parse an individual line:
```c#
var input = "http_requests_total{method=\"post\",code=\"200\"} 1027 1395066363000";
var result = Prometheus.ParseLine(input);
if(result.IsMetric)
{
var metric = result as Metric;
}
```
### Metric to string
You can also create correctly formatted Prometheus strings for `comment`, `help`, and `metric` lines.
#### F#
```f#
open Fennel
let prometheusString = Prometheus.metric "http_requests_total" 1027. [("method","post");("code","200")] DateTimeOffset.UtcNow
```
#### C#
```c#
using Fennel.CSharp;
var labels = new Dictionary{ {"method", "post"}, {"code", "200"} };
var prometheusString = Prometheus.Metric("http_requests_total", 1027, labels, DateTimeOffset.UtcNow);
```