docs: update test-container docs (#11244)

docs/INTEGRATION_TESTS.md

@@ -47,27 +47,114 @@ defer func() {
 }()
 ```
 
-The `servicePort` is the port the service is running on and Telegraf will
-connect to. When the port is specified as a single value (e.g. `11211`) then
-testcontainers will generate a random port for the service to start on. This
-way multiple tests can be run and prevent ports from conflicting.
+User's should start the container and then defer termination of the container.
 
-The `test.Container` type requires at least the following three items:
+The `test.Container` type requires at least an image, ports to expose, and a
+wait stanza. See the following to learn more:
+
+### Images
+
+Images are pulled from [DockerHub][2] by default. When looking for and
+selecting an image from DockerHub, please use the following priority order:
+
+1. [Official Images][3]: these images are generally produced by the publisher
+  themselves and are fully supported with great documentation. These images are
+  easy to spot as they do not have an author in the name (e.g. "mysql")
+2. Publisher produced: not all software has an entry in the above Official
+  Images. This may be due to the project being smaller or moving faster. In
+  this case, pull directly from the publisher's DockerHub whenever possible.
+3. [Bitnami][4]: If neither of the above images exist, look at the images
+  produced and maintained by Bitnami. They go to great efforts to create images
+  for the most popular software, produce great documentation, and ensure that
+  images are maintained.
+4. Other images: If, and only if, none of the above images will work for a
+  particular use-case, then another image can be used. Be prepared to justify,
+  the use of these types of images.
+
+### Ports
+
+When the port is specified as a single value (e.g. `11211`) then testcontainers
+will generate a random port for the service to start on. This way multiple
+tests can be run and prevent ports from conflicting.
+
+The test container will expect an array of ports to expose for testing. For
+most tests only a single port is used, but a user can specify more than one
+to allow for testing if another port is open for example.
+
+On each container's DockerHub page, the README will usually specify what ports
+are used by the container by default. For many containers this port can be
+changed or specified with an environment variable.
+
+If no ports are specified, a user can view the image tag and view the various
+image layers. Find an image layer with the `EXPOSE` keyword to determine what
+ports are used by the container.
+
+### Wait Stanza
+
+The wait stanza lays out what test containers will wait for to determine that
+the container has started and is ready for use by the test. It is best to
+provide not only a port, but also a log message. Ports can come up very early
+in the container, and the service may not be ready.
+
+To find a good log message, it is suggested to launch the container manually
+and see what the final message is printed. Usually this is something to the
+effect of "ready for connections" or "setup complete". Also ensure that this
+message only shows up once, or the use of the
+
+### Other Parameters
+
+There are other optional parameters that user can make use of for additional
+configuration of the test containers:
+
+- `BindMounts`: used to mount local test data into the container. The order is
+  location in the container as the key and the local file as the value.
+- `Entrypoint`: if a user wishes to override the entrypoint with a custom
+  command
+- `Env`: to pass environmental variables to the container similar to Docker
+  CLI's `--env` option
+- `Name`: if a container needs a hostname set or expects a certain name use
+  this option to set the containers hostname
+- `Networks`: if the user creates a custom network
 
-1. An image name from [DockerHub][2], which can include a specific tag or not
-2. An array of port(s) to expose to the test to connect to
-3. A wait stanza. This lays out what testcontainers will wait for to determine
-  that the container has started and is ready for use by the test. It is best
-  to provide not only a port, but also a log message. Ports can come up very
-  early in the container, and the service may not be ready.
+[1]: <https://golang.testcontainers.org/> "testcontainers-go"
+[2]: <https://hub.docker.com/> "DockerHub"
+[3]: <https://hub.docker.com/search?q=&type=image&image_filter=official> "DockerHub Official Images"
+[4]: <https://hub.docker.com/u/bitnami> "Bitnami Images"
 
-There are other optional parameters like `Env` to pass environmental variables
-to the container or `BindMounts` to pass test data into the container as well.
+## Network
 
-User's should start the container and then defer termination of the container.
+By default the containers will use the bridge network where other containers
+cannot talk to each other.
 
-[1]: <https://golang.testcontainers.org/> "testcontainers-go"
-[2]: <https://hub.docker.com/> "DockerHub"
+If a custom network is required for running tests, for example if containers
+do need to communicate, then users can set that up with the following code:
+
+```go
+networkName := "test-network"
+net, err := testcontainers.GenericNetwork(ctx, testcontainers.GenericNetworkRequest{
+    NetworkRequest: testcontainers.NetworkRequest{
+        Name:           networkName,
+        Attachable:     true,
+        CheckDuplicate: true,
+    },
+})
+require.NoError(t, err)
+defer func() {
+    require.NoError(t, net.Remove(ctx), "terminating network failed")
+}()
+```
+
+Then specify the network name in the container startup:
+
+```go
+zookeeper := testutil.Container{
+    Image:        "wurstmeister/zookeeper",
+    ExposedPorts: []string{"2181:2181"},
+    Networks:     []string{networkName},
+    WaitingFor:   wait.ForLog("binding to port"),
+    Name:         "telegraf-test-zookeeper",
+}
+```
 
 ## Contributing