ARCHITECTURE.md

Andrew has two primary concepts: the Server and the Page.

The Server owns:

• answering questions about the layout of files in the directory structure
• understanding the kinds of file that are being served
• serving those files If you are answering a question about files, the Server's got the answers. The server creates Pages and serves those Pages.

The Page owns the content and metadata.

Page tracks the content of a specific file and various pieces of metadata about it.

For example, the page parses the contents of a file and parses out the andrew metadata headers, so that when the Server wants to present those elements to an end-user they're already built.

Metric Names

Andrew exposes prometheus metrics, serving on /metrics.

The naming scheme is case-preserving.

The scheme is:

flowchart TD
    A[packagename_] --> B{Is there a type that owns the function?}
    B -->|yes| C[typename_]
    B -->|no| D[functionname_]
    C --> D[functionname_]
    D --> F[conceptname]
    F --> |sorted by labels| G[bylabel]

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definitions

packagename_ : the name of the package containing the function, followed by an underscore e.g. andrew_ typename_ : the name of the type which owns the function being instrumented e.g. AndrewServer_. If the function is owned by a package without an associated type, skip this. functionname_ : the name of the function being instrumented, followed by an underscore e.g. Serve_ conceptname: what conceptually are we instrumenting here? For example, in the code below we are instrumenting noises. bylabel:

package roflcopter

import (
    "github.com/prometheus/client_golang/prometheus/promauto"
    "github.com/prometheus/client_golang/prometheus"
)

func noise(noiseType string) {
    switch noiseType {
    case "soisoisoi":
        promauto.NewCounter(prometheus.CounterOpts{
            Name: "roflcopter_noise_soisoisoi",
            Help: "The total number of soisoisoi noises the roflcopter made",
        }).Inc()
    case "explosion"
        promauto.NewCounter(prometheus.CounterOpts{
            Name: "roflcopter_noise_explosion",
            Help: "The total number of explosion noises the roflcopter made",
        }).Inc()
    default:
        // Handle unknown noise types if needed
        promauto.NewCounter(prometheus.CounterOpts{
            Name: "roflcopter_noise_unknownnoise",
            Help: "The total number of unknown noises the roflcopter made",
        }).Inc()
    }
}