eslp - Elastic Stack Local Proxy

eslp is a localhost proxy to elastic stack servers. It provides:

• an unauthenticated CORS-friendly http server running on localhost
• that proxies to authenticated elastic servers running elsewhere
• via a locally available DNS host names

install

npm install -g pmuellr/eslp

or run via

npx pmuellr/eslp

usage

eslp [options] 

options:

short	long	description
-h	--help	display help
-d	--debug	generate verbose output when running
-v	--version	print version
-p	--port <num>	use this port number instead of default 19200
-c	--config <file>	use this config file instead of ~/.eslp.toml
-o	`--output plain	env`

Once started, the proxy will become available and populate local DNS with host names for each proxy. For example: (using -o env)

eslp: handling servers:

# local
export ES_URL=http://local-es.eslp.local:19200
export KB_URL=http://local-kb.eslp.local:19200

# pmuellr-8-9-0
export ES_URL=http://pmuellr-8-9-0-es.eslp.local:19200
export KB_URL=http://pmuellr-8-9-0-kb.eslp.local:19200

# pmuellr-8-9-0-apikey
export ES_URL=http://pmuellr-8-9-0-apikey-es.eslp.local:19200
export KB_URL=http://pmuellr-8-9-0-apikey-kb.eslp.local:19200

eslp: server started on port 19200, access at https://proxy.eslp.local:19200/

Each host name is an alias to localhost, and so each HTTP request to that port will be disambiguated via it's Host header.

The DNS entries are only available on your local network, given the .local suffix. That's good and bad. The proxies aren't available via DNS outside your own local network which is great. The proxies ARE available via DNS within your own network, but the server only accepts connections from localhost. That means two separate machines on the same local network may fight over these names. If that becomes a problem, there is likely some straight-forward fix like allowing another string in the DNS names.

When this program runs, it writes the names of the hosts it's proxying to stdout. When you press the "Enter" key at the terminal this program is running, it will reload the config file - but just the servers, not the port. If you edit and save the config file, the config file will also be reloaded, but the port (if specified) will be ignored.

config file

The config file is a TOML file describing the operation of eslp.

It must be in mode '600' (user: read/write, group/world: no access). To make your config file mode '600', use the command:

chmod 600 my-config-file-name.toml

The following properties can be used:

• port - the port to run on, overrideable on the command line
• cert - TLS certificate file to run the servers as https
• key - TLS key file to run the servers as https
• servers - an array of server entries, see below.
• cors - contains two properties, origins and methods, both arrays of strings

The cert property should be a file name of a TLS certificate to use when running the server as https servers instead of http servers. See the cert directory for some instructions on building the certificate, which should be self-signed and set up with a wild card for all the hosts running under the server.

When using the cert property, you must also use the key property. A key file is also generated in the cert directory.

The cors property is required when you want CORS support. You must list the origins that will be accessing the proxy, and the methods that are allowed to be used. And example which allows GET and POST requests from two hosts - a localhost one and a GitHub pages one is below.

[cors]
	origins = [ "http://localhost:3000", "https://pmuellr.github.io" ]
	methods = [ "GET", "POST" ]

The server property is an array of objects. The default server objects configured are specified as:

port = 19200

[[server]]
name   = "local"
es     = "http://localhost:9200"
kb     = "http://localhost:5601"
user   = "elastic"
pass   = "changeme"

[[server]]
name   = "locals"
es     = "https://localhost:9200"
kb     = "https://localhost:5601"
user   = "elastic"
pass   = "changeme"

The name property will be used as the part of the host name of proxy generated for this server.

The es and kb properties are the URLs to Elasticsearch and Kibana. I guess there could be more later.

Rather than use user and pass, you can use apiKey.

change log

1.0.8 - 2024-07-04

• add pretty much mandatory cors options in config

1.0.7 - 2024-06-26

• add CORS headers to https://proxy.eslp.local/index.json

1.0.6 - 2024-05-04

• add --output / -o option to output server in plain or env var format

1.0.5 - 2024-02-01

• add http[s]://proxy.eslp.local to provide basic web page and JSON index

1.0.4 - 2024-01-30

• add https support

1.0.3 - 2023-09-06

• fix up a few things

1.0.2 - 2023-09-01

• reload config file when expected

1.0.1 - 2023-08-21

• remove interstitial .eslp from domain names (eg http://local.es.eslp.eslp.local:19200)

1.0.0 - 2023-08-19

• initial working version

license

This package is licensed under the MIT license. See the LICENSE.md file for more information.

contributing

Awesome! We're happy that you want to contribute.

Please read the CONTRIBUTING.md file for more information.