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[](https://goreportcard.com/report/git.darknebu.la/GalaxySimulator/generator-container)
# generator-container
-the generator generates a star using the NFW-profile-api
\ No newline at end of file
+The generator container generates stars by [random-sampling](https://en.wikipedia.org/wiki/Simple_random_sample) random values on the [Navarro-Frenk-White profile](https://en.wikipedia.org/wiki/Navarro%E2%80%93Frenk%E2%80%93White_profile).
+
+In order to do so, it functions as a manager-container creating random stars.
+In the end, the generator container doesn't calculate the NFW-values by itself, but accesses the [NFW-containers](https://git.darknebu.la/GalaxySimulator/NFW-container) that
+is specialized on this job.
+
+This has the advantage that a lot of manager containers can be started an the generator container
+interacts with a reverse proxy such as [traefik](https://traefik.io) that load-balances the request.
+The complete process of generating stars can though be speed up a lot.
+
+Instructing the generator container about where to look for the nfw-containers works in the
+following way: simply set the environment variable `nfwurl` to the base-url of the nfw-container or proxy.
+
+## Examples
+
+- single nfw-container
+
+ Let's suppose we've got a generator-container running on `localhost:8080` and we want it
+ to access the nfw-container running on `localhost:8081`. The solution is to simply set the
+ `nfwurl` to `localhost:8081`:
+ ```bash
+ $ go build . -o generator
+ $ nfwurl=localhost:8081 ./generator
+ ```
+ As soon as we access the /gen endpoint of the generator endpoint, the generator generates
+ a random star and makes a request to the NFW-container with the coordinates of the star.
+ The nfw-container returns the NFW-value of the given star and allows the generator container
+ to continue testing if the star exists or not.
+
+- multiple nfw-containers
+
+ Let's suppose the amount of stars we want to generate is really big and generating them on
+ a single host is not fast enough: the solution is to use more hardware!
+
+ So let's assume we've got multiple nodes running in a docker-swarm environment that uses
+ traefik as a reverse-proxy. We instruct the generator-container to use the nfw.docker.localhost
+ endpoint that is balanced through traefik.
+ ```bash
+ $ go build . -o generator
+ $ nfwurl=nfw.docker.localhost ./generator
+ ```
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