Flownative Nginx Image

A Docker image providing Nginx for Beach, Local Beach and other purposes. Compared to other Nginx images, this one provides specific features which come in handy for running a Neos CMS instance or Neos Flow application.

tl;dr

$ docker run flownative/nginx

Hosting a Neos website or Flow application

tbd.

Hosting a static website

Set the environment variable "BEACH_NGINX_MODE" to "Static" and optionally set the variable "NGINX_STATIC_ROOT" to the path leading to the root of your static site.

The BEACH_NGINX_MODE variable follows legacy naming and will be renamed / replaced by another concept in the future.

Configuration

Logging

By default, the access log is written to STDOUT, and the error log is redirected to STDERR. That way, you can follow logs by watching container logs with docker logs or using a similar mechanism in Kubernetes or your actual platform.

Additionally, logs are also stored in /opt/flownative/log/nginx-error.log and /opt/flownative/log/nginx-access.log. If the log format is "json", the access log file is /opt/flownative/log/nginx-access.json.log

Note that the error log only contains errors related to the webserver itself. Requests resulting in status codes like 404 (not found) or 503 (internal server error) are logged to the access log, if it is enabled.

The log level for the error log can be defined via the NGINX_LOG_LEVEL environment variable. See the Nginx documentation for possible values. The default value is warn.

The access log is disabled by default, it can be enabled by setting NGINX_ACCESS_LOG_ENABLE to "true".

The access log's default format is similar to the standard Nginx "combined" format with a few additions, so that the IP address of the original request is shown since this Nginx is usually operated behind a reverse proxy.

Instead of the default format, a JSON format can be used by setting NGINX_ACCESS_LOG_FORMAT to "json".

The access log may contain a lot of entries, if enabled. If you are only interested in requests resulting in certain status codes (for example internal server errors), you can define a regular expression which filters out other log entries. Setting NGINX_ACCESS_LOG_IGNORED_STATUS_CODES_REGEX to "^[234]" will ignore all responses whose status code starts with "2", "3" or "4" respectively. Therefore, only 5xx errors will then end up in the access log.

By default, connection-related status (1xx) and redirects (3xx) will be ignored.

NOTE: Be careful when specifying the regular expression, because syntax errors might keep Nginx from starting.

Environment variables

Variable Name	Type	Default	Description
NGINX_BASE_PATH	string	/opt/flownative/nginx	Base path for Nginx
NGINX_ERROR_LOG_LEVEL	string	warn	Nginx log level (see documentation)
NGINX_ACCESS_LOG_ENABLE	boolean	no	Nginx log level (see documentation)
NGINX_ACCESS_LOG_FORMAT	string	default	Format of the access log; possible values are "default" and "json"
NGINX_ACCESS_LOG_MODE	string	dynamic	Defines which requests should be logged: "dynamic" only logs dynamic requests to PHP, "all" also includes requests to static files
NGINX_ACCESS_LOG_IGNORED_STATUS_CODES_REGEX	string	^[13]	Regular expression which defines which status codes should NOT be logged into the access log
NGINX_CACHE_ENABLE	boolean	no	If the FastCGI cache should be enabled; see section about caching
NGINX_CACHE_NAME	string	application	Name of the memory zone Nginx should use for caching
NGINX_CACHE_DEFAULT_LIFETIME	string	5s	Default cache lifetime to use when caching is enabled
NGINX_CACHE_MAX_SIZE	string	1024m	Maximum memory size for the FastCGI cache
NGINX_CACHE_INACTIVE	string	1h	Time after which cache entries are removed automatically
NGINX_CACHE_USE_STALE_OPTIONS	string	updating error timeout invalid_header	Options to pass to the fastcgi_cache_use_stale directive
NGINX_CACHE_BACKGROUND_UPDATE	boolean	off	If background updates should be enabled
NGINX_CUSTOM_ERROR_PAGE_CODES	string	500 501 502 503	FastCGI error codes which should redirect to the custom error page; codes are separated by spaces
NGINX_CUSTOM_ERROR_PAGE_TARGET	string		Upstream URL to use for custom FastCGI error pages, for example https://example.com/maintenance.html
NGINX_STATIC_ROOT	string	/var/www/html	Document root path for when BEACH_NGINX_MODE is "Static"
NGINX_STRICT_TRANSPORT_SECURITY_ENABLE	boolean	no	If Strict-Transport-Security headers should be sent (HSTS)
NGINX_STRICT_TRANSPORT_SECURITY_PRELOAD	boolean	no	If site should be added to list of HTTPS-only sites by Google and others
NGINX_STRICT_TRANSPORT_SECURITY_MAX_AGE	boolean	31536000	Maxmimum age for Strict-Transport-Security header, if enabled
NGINX_AUTH_BASIC_REALM	string	off	Realm for HTTP Basic Authentication; if "off", authentication is disabled
NGINX_AUTH_BASIC_USERNAME	string		Username for HTTP Basic Authentication
NGINX_AUTH_BASIC_ENCODED_HASHED_PASSWORD	string		Base64-encoded hashed password (using httpasswd) for HTTP Basic Authentication
NGINX_ENABLE_UNDERSCORES_IN_HEADERS	boolean	no	Enables or disables the use of underscores in client request header fields.
BEACH_NGINX_CUSTOM_METRICS_ENABLE	boolean	no	If support for a custom metrics endpoint should be enabled
BEACH_NGINX_CUSTOM_METRICS_SOURCE_PATH	string	/metrics	Path where metrics are located
BEACH_NGINX_CUSTOM_METRICS_TARGET_PORT	integer	8082	Port at which Nginx should listen to provide the metrics for scraping
BEACH_NGINX_MODE	string	Flow	Either "Flow" or "Static"; this variable is going to be renamed in the future
BEACH_ASSET_PROXY_ENDPOINT	string		Endpoint of a cloud storage frontend to use for proxying requests to Flow persistent resources. Requires BEACH_PERSISTENT_RESOURCES_BASE_PATH to be set. Example: "https://assets.flownative.com/example-bucket/"
BEACH_ASSET_PROXY_RESOLVER	string	8.8.8.8	IP address of a DNS server to use for resolving domains when proxying assets. Set this to 127.0.0.11 when using Local Beach.
BEACH_PERSISTENT_RESOURCES_BASE_PATH	string		Base path of URLs pointing to Flow persistent resources; example: "https://www.flownative.com/assets/"
BEACH_STATIC_RESOURCES_LIFETIME	string	30d	Expiration time for static resources; examples: "3600s" or "7d" or "max"
FLOW_HTTP_TRUSTED_PROXIES	string	10.0.0.0/8	Nginx passes FLOW_HTTP_TRUSTED_PROXIES to the virtual host using the value of this variable

Asset Proxy

By default, the direct URL of an asset stored in the cloud storage is used as part of the Flow or Neos frontend output. In order to make URLs more user-friendly or hide the fact that assets are stored in a cloud storage, Nginx can act as a reverse proxy and make assets available through a sub-path of the website's main domain.

For example, if the website is reachable via "https://www.example.com", the proxy can be configured to map the path "https://www.example.com/assets/" to assets stored in a cloud storage bucket which is accessible at "https://some.cloud.storage/some-bucket/".

The environment variables to set for the above example are as follows:

BEACH_PERSISTENT_RESOURCES_BASE_PATH=/assets/
BEACH_ASSET_PROXY_ENDPOINT=https://some.cloud.storage/some-bucket

Note: Make sure that both values are formatted exactly like in the given examples, for example don't forget the trailing "/" in BEACH_PERSISTENT_RESOURCES_BASE_PATH and don't add a trailing "/" in "BEACH_ASSET_PROXY_ENDPOINT".

Security aspects

This image is designed to run as a non-root container. Using an unprivileged user generally improves the security of an image, but may have a few side effects, especially when you try to debug something by logging in to the container using docker exec.

When you are running this image with Docker or in a Kubernetes context, you can take advantage of the non-root approach by disallowing privilege escalation:

$ docker run flownative/nginx:latest --security-opt=no-new-privileges

Because Nginx runs as a non-root user, it cannot bind to port 80 and users port 8080 instead. Since you can map that port to any other port by telling Docker or Kubernetes, this won't be a problem in practice. However, be aware that you need to specify 8080 as the container port – otherwise you won't get a connection.