NATS.io NATS by Example Slack NATS Docs

Basics

Basic configuration revolves around 4 settings:

  • The store to read JWTs from

  • The HTTP/S configuration

  • NATS (for cases where updates are enabled)

  • Logging

For complete information, please refer to the project's Github.

Directory Configuration

You can start a server using a plain directory. In this case you'll be responsible for adding any JWT that you want resolved.

The server looks for account JWTs by using the public key of the account as the file name followed by the extension .jwt. The server will not introspect the JWTs, so if you don't name the files correctly, it will fail to find them or serve a JWT that doesn't match the requested account.

mkdir /tmp/jwts
nats-account-server -dir /tmp/jwts
2019/05/10 11:33:40.501305 [INF] starting NATS Account server, version 0.0-dev
2019/05/10 11:33:40.501383 [INF] server time is Fri May 10 11:33:40 CDT 2019
2019/05/10 11:33:40.501404 [INF] creating a store at /tmp/jwts
2019/05/10 11:33:40.501430 [INF] NATS is not configured, server will not fire notifications on update
2019/05/10 11:33:40.510273 [INF] http listening on port 9090
2019/05/10 11:33:40.510283 [INF] nats-account-server is running
2019/05/10 11:33:40.510285 [INF] configure the nats-server with:
2019/05/10 11:33:40.510291 [INF]   resolver: URL(http://localhost:9090/jwt/v1/accounts/)

Configuration for the NATS server is the same as in the previous example:

operator: /Users/synadia/.nsc/nats/Test/Test.jwt
resolver: URL(http://localhost:9090/jwt/v1/accounts/)

A step by step tutorial using directory configuration can be found here.

Configuration File

While the -dir store flag is sufficient for some very simple developer setups, any production or non-read-only server will require a configuration file.

Let's take a look at the configuration options:

Configuration Options

OptionDescription

http

An http configuration block specifying HTTP options.

logging

A logging configuration block specifying server logging options.

nats

A nats configuration block specifying NATS connection information for the account server to push JWT changes to a NATS server.

operatorjwtpath

The path to an operator JWT. Required for non-read-only servers. Only JWTs signed by the operator (or one of it's signing keys) are accepted.

store

A store configuration block specifying store options.

systemaccountjwtpath

Path to an Account JWT that should be returned as the system account.

primary

URL for the primary, protocol://host:port.

replicationtimeout

Timeout, in milliseconds, used by the replica when talking to the primary, defaults to 5000.

store Configuration

OptionDescription

dir

Configures a directory as a store.

readonly

If true, the store will not accept POST requests. Note that to receive requests, the store must also have operatorjwtpath specified as a root option.

shard

If true, JWTs will be stored in multiple sub directories of the store directory.

logging Options

OptionDescription

time

If true, a timestamp is added to log messages.

debug

If true, debug messages are logged.

trace

If true, trace messages are logged.

colors

If true, messages are logged using ANSI color escape sequences.

pid

If true, the process id for the server is added to log messages.

http Options

OptionDescription

host

Interface to listen for requests on.

port

Port to listen for requests on.

readtimeout

Max amount of time in milliseconds to wait for a http read operation to complete.

writetimeout

Max amount of time in milliseconds to wait for a http write operation to complete.

nats Options

OptionDescription

servers

List of NATS servers for the account server to use when connecting to a NATS server to publish updates.

connecttimeout

Max amount of time in milliseconds to wait for a NATS connection.

reconnecttimewait

Amount of time in milliseconds to between NATS server reconnect attempts.

tls

A tls configuration block.

usercredentials

A credentials creds file for connecting to the NATS server. Account must be a member of a system account.

tls Options

OptionDescription

root

filepath to the CA certificate.

cert

filepath to the certificate.

cert

filepath to the certificate key.

Example Setup

Provided a setup with 4 accounts, one of them a system account, this example shows how to set up the account server by:

  • adding the account server to the operator

  • configuring the account server

  • push the accounts to the account server

  • configure a nats-server to make use of the account server

  • test the setup

Set environment variables

export NKEYS_PATH=$(pwd)/nsc/nkeys
export NSC_HOME=$(pwd)/nsc/accounts

Run setup script that creates a few sample accounts and a system account

curl -sSL https://nats-io.github.io/k8s/setup/nsc-setup.sh | sh

List all accounts

nsc list accounts
╭─────────────────────────────────────────────────────────────────╮
│                            Accounts                             │
├──────┬──────────────────────────────────────────────────────────┤
│ Name │ Public Key                                               │
├──────┼──────────────────────────────────────────────────────────┤
│ A    │ AA6LOQIZRKEAC5FUGLMZHAXERZRQFAFQOO7YC6ZMQ325BYUAEPDUEIV5 │
│ B    │ ACPD2M7QFV33HPPY563PI7C664LXG2YVWXQBB6EAHDXZR7EK7L52AWUG │
│ STAN │ ABD4DPO745A5U2JKPWCI7LFGW4UCTN5LPUXDA5BCMXEYWLCU7J346NGU │
│ SYS  │ AB25DCM6BL5SDWYR45F65MSVOVXATN64AZXGI7IGS3IXBPWWDB4FIR2H │
╰──────┴──────────────────────────────────────────────────────────╯

Add the endpoint for the account server to which accounts can be published

nsc edit operator --account-jwt-server-url http://localhost:9090/jwt/v1/ --service-url nats://localhost:4222

Generate account server config that references the operator jwt

echo '
operatorjwtpath: "./nsc/accounts/nats/KO/KO.jwt"

http {
    port: 9090
}
' > nats-account-server.conf

Start the account server

nats-account-server -c nats-account-server.conf &

Upload the local accounts in the nsc directory structure

nsc push -A

Generate the NATS Server config that points to the account server

echo '
operator: "./nsc/accounts/nats/KO/KO.jwt"
resolver: URL(http://localhost:9090/jwt/v1/accounts/)
system_account: AB25DCM6BL5SDWYR45F65MSVOVXATN64AZXGI7IGS3IXBPWWDB4FIR2H
' > nats-server.conf

Start the NATS Server in trusted operator mode

nats-server -c nats-server.conf &

Try to subscribe on account without permissions, this should fail

nats sub -creds nsc/nkeys/creds/KO/A/test.creds foo
nats: Permissions Violation for Subscription to "foo"

Subscribe then publish to subject should work on 'test' since enough permissions

nats sub -creds nsc/nkeys/creds/KO/A/test.creds test &

Published message on 'test' subject would be received by started subscriber above

nats pub -creds nsc/nkeys/creds/KO/A/test.creds test foo &

Subscribe using the system account user credentials can receive all system events

nats sub -creds nsc/nkeys/creds/KO/SYS/sys.creds '>'
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