tricorder

Automation the KISS way.

Introduction

Ansible is a great tool for automation. But it suffers from the same problem of many such tools: a big pile of custom YAML DSL.

YAML is used to provide a declarative syntax of your automated workflow. This is nice for simple use cases, but automation can become rather complex very quickly.

But once those tools start implementing:

• control flow structures (conditions, loops)
• variable assignations
• modules
• package management
• ...

Your YAML files become a programming language with terrible developer experience.

tricorder aims to fix this. It gives you a single tool to perform tasks on multiple remotes. You then use your common UNIX tools like bash, jq, curl, etc... to compose those tasks together.

Usage

Just like Ansible, tricorder uses an inventory file, listing the hosts to connect to:

[[hosts]]

id = "backend"
tags = ["server", "backend", "myapp"]
address = "10.0.1.10:22"
user = "admin"

[[hosts]]

id = "frontend"
tags = ["server", "frontend", "myapp"]
address = "10.0.1.20:22"
user = "admin"

NB: The inventory is either a TOML file or an executable producing a JSON output. This way you can create dynamic inventories by querying a remote service or database.

Then, run one of the following commands:

$ tricorder -i /path/to/inventory do -- echo "run on all hosts"
$ tricorder -i /path/to/inventory -H backend do -- echo "run on specific host"
$ tricorder -i /path/to/inventory -t "server & myapp" do -- echo "run on all hosts matching tags"

Or to run concurrently instead of sequencially:

$ tricorder -i /path/to/inventory do -p -- echo "run on all hosts"
$ tricorder -i /path/to/inventory -H backend do -p -- echo "run on specific host"
$ tricorder -i /path/to/inventory -t "server & myapp" do -p -- echo "run on all hosts matching tags"

NB: Authentication is done via ssh-agent only.

Every logging messages is written on stderr, the command result for each host is written as a JSON document on stdout:

[
  {
    "host": "backend",
    "success": false,
    "error": "..."
  },
  {
    "host": "frontend",
    "success": true,
    "info": {
      "exit_code": 0,
      "stdout": "...",
      "stderr": "...",
    }
  }
]

This way, you can compose this tool with jq to extract the relevant informations in your scripts.

Usage with the Rust API

tricorder is also available as a Rust crate to include it directly in your software:

use tricorder::prelude::*;
use tricorder::tasks::exec;
use serde_json::json;

let inventory = Inventory::new()
  .add_host(
    Host::new(Host::id("localhost").unwrap(), "localhost:22".to_string())
      .set_user("root".to_string())
      .add_tag(Host::tag("local").unwrap())
      .set_var("msg".to_string(), json!("hello"))
      .to_owned()
  )
  .to_owned();

let task = exec::Task::new("echo \"{host.id} says {host.vars.msg}\"".to_string());

// Run the task sequentially:
let result = inventory.hosts.run_task_seq(&task).unwrap();
// Run the task concurrently:
let result = inventory.hosts.run_task_parallel(&task).unwrap();

println!("{}", result);

Documentation

For more informations, consult the documentation.

Roadmap

Checkout the Bug Tracker.

License

This software is released under the terms of the MIT License.