nginx is a popular reverse proxy server among node developers. It's common to set up one or more node apps listening on high-numbered ports and use nginx virtual hosting and reverse proxy features to pass traffic to node. nginx can also serve static files better than node can, and it has battle-testd round-robin load balancing features.
We've boiled down our favorite configuration recipes for nginx to a simple utility that takes care of spinning up and shutting down proxies for new node sites on a server. It can also handle load balancing, canonical redirects, direct delivery of static files and https configuration. It takes the place of manually editing nginx configuration files.
Step One: install nginx on your Linux server.
Under Ubuntu Linux that would be:
apt-get install nginx
Make sure Apache isn't in the way, already listening on port 80. Remove it really, really thoroughly. Or reconfigure it for an alternate port, like 9898, and set it up as a fallback as described below.
Step Two:
npm install -g mechanic
NOTE: mechanic will reconfigure nginx after each command given to it. A strong effort is made not to mess up other uses of nginx. Mechanic's nginx configuration output is written to /etc/nginx/conf.d/mechanic.conf, where both Debian-flavored and Red Hat-flavored Linux will load it. No other nginx configuration files are touched. You can change the folder where mechanic.conf is written, see below.
Step Three:
Go nuts.
Let's add a single proxy that talks to one node process, which is listening on port 3000 on the same server (localhost):
All commands must be run as root.
(Optional) Step Four:
Install letsencrypt for automatic host certification or configure your own certificate provider.
mechanic add mysite --host=mysite.com --backends=3000
Replace mysite with a good "shortname" for your site— letters and numbers and underscores only, no leading digits.
mechanic will reconfigure and restart nginx as you go along and remember everything you've asked it to include.
Next we decide we want some aliases: other hostnames that deliver the same content. It's common to do this in the pre-launch period. With the update command we can add new options to a site without starting from scratch:
mechanic update mysite --aliases=www.mysite.com,mysite.temporary.com
In production, it's better to redirect traffic so that everyone sees the same domain. Let's start redirecting from our aliases rather than keeping them in the address bar:
mechanic update mysite --canonical=true
We've realized this site should be the default site for the entire server. If a request arrives with a hostname that doesn't match any --host or --aliases list, it should always go to this site, redirecting first if the site is canonical. We can do that with default:
mechanic update mysite --default=true
Warning: If your server came with a default website already configured,
like the server block that appears in /etc/nginx/nginx.conf in
CentOS 7, you will need to comment that out to use this feature. mechanic
does not mess with the rest of your nginx settings, that is up to you.
Let's score a big performance win by serving our static files directly with nginx. This is simple: if a file matching the URL exists, nginx will serve it directly. Otherwise the request is still sent to node. All we have to do is tell nginx where our static files live.
mechanic update mysite --static=/opt/stagecoach/apps/mysite/current/public
Browsers will cache the static files for up to 7 days. That's a good thing, but if you use this feature make sure any dynamically generated files have new filenames on each new deployment.
When using --static, you can optionally enable serving index.html automatically when a URL matches a directory name by using the --autoindex option.
mechanic update mysite --autoindex
As with all boolean options you can change your mind later:
mechanic update mysite --autoindex=false
In a typical proxy configuration, this makes it possible to use an index.html file as a cached static version of a resource with a "pretty URL" like /people that would normally hit your back end server.
Although static websites will never be a primary use case for mechanic, you can set up a perfectly reasonable static webserver like this:
mechanic add mysite --host=mysite.com --static=/var/www/html/mysite --autoindex
The backends option is no longer mandatory when --static is present.
If you have more elaborate use cases that don't involve a reverse proxy, you should really create a separate nginx configuration file for that site.
Traffic is surging, so we've set up four node processes to take advantage of four cores. They are listening on ports 3000, 3001, 3002 and 3003. Let's tell nginx to distribute traffic to all of them:
mechanic update mysite --backends=3000,3001,3002,3003
This time we want to load-balance between two separate back-end servers, each of which is listening on two ports:
mechanic update mysite --backends=192.168.1.2:3000,192.168.1.2:3001,192.168.1.3:3000,192.168.1.3:3001
You can use hostnames too.
Now we've added ecommerce and we need a secure site:
mechanic update mysite --https=true
Now nginx will serve the site with https (as well as http) and look for mysite.cer and mysite.key in the folder /etc/nginx/certs.
See the nginx docs on how to handle intermediate certificates.
Next we decide we want the site to be secure all the time, redirecting any traffic that arrives at the insecure site:
mechanic update mysite --https=true --redirect-to-https=true
You may use a certificate authority to automatically get SSL certificates for the hostnames on your site.
letsencrypt is included by default.
You may add more providers as shell scripts in /etc/nginx/mechanic-certproviders.
The files can be nunjucks templates, where the following variables are available:
hosts: array of hostnames configured for your site, including aliases
name: the name of your site
host: your site's default host
To automatically generate certificates for a site, add the --certify flag to your site configuration, like so:
mechanic update mysite --certify=true
or
mechanic add mysite --host=example.com --aliases=example1.com,example2.com --https=true --certify=true
To change the global certificate provider, run
mechanic set certProvider myCertProvider
where myCertProvider is the name of the file you've created in /etc/nginx/mechanic-certproviders.
You may change the certificate provider per site.
To do so, run
mechanic update mysite --certProvider=myCertProvider --certify
For the default letsencrypt provider, certificates are symlinked to the configuration folder,
so you can use letsencrypt renew to renew all your certificates automatically.
Now we've decided we don't want ecommerce anymore. Let's shut that off:
mechanic update mysite --https=false
Now let's remove the site completely:
mechanic remove mysite
You can disable any previously set option, such as static, by setting it to false or the empty string.
If you also want to serve some content with Apache on the same server, first configure Apache to listen on port 9898 instead of 80, then set up a default site for mechanic that forwards traffic there:
mechanic add apache --host=dummy --backends=9898 --default=trueWe still need a host setting even for a default site (TODO: remove this requirement).
Apache doesn't have to be your default. You could also use --host and set up individual sites to be forwarded to Apache.
There are a few global options you might want to change. Here's how. The values shown are the defaults.
mechanic set conf /etc/nginx/conf.dThis is the folder where the mechanic.conf nginx configuration file
will be created. Note that both Red Hat and Debian-flavored Linux
load everything in this folder by default.
mechanic set restart "nginx -s reload"The command to restart nginx.
Don't forget the quotes if spaces are present. That's just how the shell works, but it bears repeating.
mechanic set logs /var/log/nginxIf this isn't where you want your nginx access and error log files for each site, change the setting.
mechanic set bind "*"By default, mechanic tells nginx to accept traffic on all IP addresses assigned to the server. (* means "everything.") If this isn't what you want, set a specific ip address with bind.
If you reset this setting to * make sure you quote it, so the shell doesn't give you a list of filenames.
mechanic set template /etc/mechanic/custom.confYou don't have to use our nginx configuration template.
Take a look at the file template.conf in the nginx npm module. It's just a nunjucks template that builds an nginx configuration based on your mechanic settings.
You can copy that template anywhere you like, make your own modifications, then use mechanic set template to tell mechanic where to find it.
If you don't want to customize our template, check out the convenience override files that mechanic creates for you:
/etc/nginx/mechanic-overrides/myshortname/top
/etc/nginx/mechanic-overrides/myshortname/server
/etc/nginx/mechanic-overrides/myshortname/location
/etc/nginx/mechanic-overrides/myshortname/proxy
top is loaded before any of mechanic's directives for that site. Use it when nothing else fits.
server is included inside the server block for the site, just before the location block, when redirect-to-https is not in effect. it is a good place to change a setting like client_max_body_size or access_log.
location is included inside the location block, and is a good place to add something like CORS headers for static font files.
proxy is loaded inside the proxy server configuration and is ideal if you need to override mechanic's proxy settings.
These files start out empty; you can add whatever you like.
Of course, if this isn't enough flexibility for your needs, you can create a custom template.
Maybe you updated mechanic with npm update -g mechanic and you want our
latest configuration. Maybe you edited your custom template. Either way,
you want to rebuild your nginx configuration without changing any
settings:
mechanic refresh
To completely reset mechanic, throwing away everything it knows:
mechanic resetWarning: like it says, this will completely reset your configuration and forget everything you've done. Don't do that unless you really want to.
mechanic list
This gives you back commands sufficient to set them up the same way again. Great for copying to another server. Here's some sample output:
mechanic set restart "/usr/sbin/nginx -s reload"
mechanic add test --host=test.com --aliases=www.test.com --canonical=true --https=true
mechanic add test2 --host=test2.com --aliases=www.test2.com,test2-prelaunch.mycompany.com
If you want to wipe the configuration on another server before applying these commands there, use mechanic reset.
You don't have to use our nginx configuration template.
Take a look at the file template.conf in the nginx npm module. It's just a nunjucks template that builds an nginx configuration based on your mechanic settings.
It's stored in /var/lib/misc/mechanic.json. That's one hundred percent correct according to the filesystem hierarchy standard, adhered to by all major Linux distributions and many other flavors of Unix. But if you absolutely insist, you can use the --data option to specify another location. You'll have to do it every time you run mechanic, though. That's why we only use this option for unit tests.
If necessary mechanic will create /var/lib/misc.
mechanic was created to facilitate our work at P'unk Avenue. We use it to host sites powered by Apostrophe.
1.0.1: Moved standard gzip directives to the start of the server block. Otherwise responses proxied through to node are not compressed. A large performance win.
1.0.0: Officially stable and following semantic versioning from here on out. Also added top and server override files and the --index option, and made backends optional when static is present. This allows the use of mechanic to set up very simple static websites.
0.1.13—0.1.14: pass the X-Forwarded-Proto header for compatibility with the secure flag for session cookies, provided that Express is configured to trust the first proxy.
Killed support for tlsv1 as it is insecure.
0.1.12: killed support for sslv3 as it is insecure.
0.1.11: parse host:port correctly with the --backends option.
0.1.10: the boring dependency was missing, this is fixed.
0.1.9: Accept backend as an alias for backends. Reject invalid hyphenated options passed to add and update, as their absence usually means you've mistyped something important. Don't crash nginx if there are no backends, just skip that site and print a warning. Use boring instead of yargs.
0.1.8: load convenience overrides from suitably named nginx configuration files.
0.1.7: set the ssl flag properly for nginx in the listen statement.
0.1.6: look in the documented place for SSL certificates (/etc/nginx/certs).
0.1.5: don't try to reject invalid arguments, as yargs helpfully introduces camel-cased versions of hyphenated arguments, causing false positives and breaking our hyphenated options. This isn't great; we should find out how to disable that behavior in yargs.
0.1.3: corrected documentation for Apache fallback strategy.
0.1.1, 0.1.2: reset command works.
0.1.0: initial release.