Merge pull request #76 from joesturge/73-store-ip-in-configtoml-instead-of-hostname-if-provided

fix: use static ip in lazymc config file if availible

Author: joesturge

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Use static IP in the lazymc.toml instead of hostname
+
+### Deprecated
+
+- The app will throw a warning if it notices you are not using a static ip for the minecraft container
+
 ## [2.2.0] - 2024-08-05
 
 ### Added

README.md

@@ -14,10 +14,39 @@ This project is also somewhat inspired by [lazytainer](https://github.com/vmorga
 
 Here is a minimal Docker Compose example using [itzg/minecraft-server](https://github.com/itzg/docker-minecraft-server) as the server:
 
+> ⚠️ It is **very important** that you assign **static** IP Address to each container. 
+This is due to quirk in how lazymc monitors the servers, it does not expect the IP address of a server to change,
+this can happen when a container stops and starts again There is an open issue for this: https://github.com/joesturge/lazymc-docker-proxy/issues/63.
+As this is an issue with lazymc itself it is unlikely that a fix can be found. Im open to suggestions on this.
+
 ```yaml
+# Lazymc requires that the minecraft server have a static IP.
+#
+# To ensure that our servers have a static IP we need to create
+# a network for our services to use.
+#
+# By default, Docker uses 172.17.0.0/16 subnet range.
+# So we need to create a new network in a different subnet
+# See the readme for more information.
+#
+# Please ensure that the subnet falls within the private CIDRs:
+# https://datatracker.ietf.org/doc/html/rfc1918#section-3
+#
+# And that it is not in use by anything else.
+networks:
+  minecraft-network:
+    driver: bridge    
+    ipam:
+      config:
+        - subnet: 172.18.0.0/16
+
 services:
   lazymc:
     image: ghcr.io/joesturge/lazymc-docker-proxy:latest
+    # the IPs should start at .2 as .1 is reserved for the gateway
+    networks:
+      minecraft-network:
+        ipv4_address: 172.18.0.2
     restart: unless-stopped
     volumes:
       # you should mount the minecraft server dir under /server, using read only.
@@ -32,6 +61,10 @@ services:
   # Standard Docker Minecraft server, also works with other server types
   mc:
     image: itzg/minecraft-server:java21
+    # Assign a static IP to the server container
+    networks:
+      minecraft-network:
+        ipv4_address: 172.18.0.3
     # We need to add a label here so that lazymc-docker-proxy knows which
     # container to manage
     labels:
@@ -59,27 +92,7 @@ volumes:
 
 This container can also proxy to and control multiple containers at once. You could use it with `itzg/mc-router` if you choose to:
 
-> ⚠️ When running multiple minecraft containers it is **very important** that you assign **static** IP Address to each container. 
-This is due to quirk in how lazymc monitors the servers, it does not expect the IP address of a server to change,
-this can happen when a container stops and starts again There is an open issue for this: https://github.com/joesturge/lazymc-docker-proxy/issues/63.
-As this is an issue with lazymc itself it is unlikely that a fix can be found. Im open to suggestions on this.
-
 ```yaml
-# Lazymc requires that the minecraft server have a static IP.
-# This generally isn't a problem when running a single server
-# as the stopped container will usually start with same IP as before.
-#
-# To ensure that our servers have a static IP we need to create
-# a network for our services to use.
-#
-# By default, Docker uses 172.17.0.0/16 subnet range.
-# So we need to create a new network in a different subnet
-# See the readme for more information.
-#
-# Please ensure that the subnet falls within the private CIDRs:
-# https://datatracker.ietf.org/doc/html/rfc1918#section-3
-#
-# And that it is not in use by anything else.
 networks:
   minecraft-network:
     driver: bridge    
@@ -196,9 +209,19 @@ volumes:
 ## Forge 1.19.2
 
 ```yaml
+networks:
+  minecraft-network:
+    driver: bridge    
+    ipam:
+      config:
+        - subnet: 172.18.0.0/16
+
 services:
   lazymc:
     image: ghcr.io/joesturge/lazymc-docker-proxy:latest
+    networks:
+      minecraft-network:
+        ipv4_address: 172.18.0.2
     restart: unless-stopped
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock:ro
@@ -208,6 +231,9 @@ services:
 
   mc:
     image: itzg/minecraft-server:java21
+    networks:
+      minecraft-network:
+        ipv4_address: 172.18.0.3
     labels:
       - lazymc.enabled=true
       - lazymc.group=mc
@@ -243,7 +269,7 @@ Here is the list of the supported container labels which can be added to the min
 which will be picked up by `lazymc-docker-proxy` (\* is required):
 
 - **\*lazymc.enabled=true** - Enable this to inform `lazymc-docker-proxy` that this container should be managed.
-- **\*lazymc.server.address** - The address of the Docker Minecraft server to manage, should use the Docker network address, such as `mc:25565`.
+- **\*lazymc.server.address** - The address of the Docker Minecraft server to manage, should use the internal Docker network address of the server container, such as `mc:25565` or the assigned static IP such as `172.18.0.3:25565`.
 - **\*lazymc.group** - This is used by `lazymc-docker-proxy` to locate the container to start and stop
 - **lazymc.port** - The port on the `lazymc-docker-proxy` container this server will be accessible from. Defaults to `25565`.
 - **lazymc.motd.sleeping** - MOTD, shown in the server browser when sleeping.
@@ -281,7 +307,7 @@ You can enable debug logging using the `RUST_LOG` env var.
 
 Here is a full list of the environment variables supported by this image (\* is required):
 
-- **\*SERVER_ADDRESS** - The address of the Docker Minecraft server to manage, should use the Docker network address, such as `mc:25565`.
+- **\*SERVER_ADDRESS** - The address of the Docker Minecraft server to manage, should use the internal Docker network address of the server container, such as `mc:25565` or the assigned static IP such as `172.18.0.3:25565`.
 - **\*LAZYMC_GROUP** - The value of the `lazymc.group` label assigned to the Docker Minecraft server. This is used by the image to start or stop the server when lazymc triggers it.
 - **LAZYMC_PORT** - The port on the `lazymc-docker-proxy` container this server will be accessible from. Defaults to `25565`.
 - **MOTD_SLEEPING** - MOTD, shown in the server browser when sleeping.

src/entrypoint/docker.rs

@@ -16,7 +16,7 @@ pub fn get_container_labels() -> Vec<HashMap<std::string::String, std::string::S
     let mut list_container_filters: HashMap<String, Vec<String>> =
         HashMap::<String, Vec<String>>::new();
 
-    // find all matching running containers which have labels starting with "lazymc."
+    // find all docker containers with the label "lazymc.enabled=true"
     list_container_filters.insert("label".to_string(), vec![format!("lazymc.enabled=true")]);
 
     // find all matching containers and then get their labels
@@ -40,6 +40,44 @@ pub fn get_container_labels() -> Vec<HashMap<std::string::String, std::string::S
         for (key, value) in container.labels.as_ref().unwrap() {
             labels.insert(key.clone(), value.clone());
         }
+
+        // parse port from lazymc.server.address label
+        let port: Option<u16> = labels
+            .get("lazymc.server.address")
+            .and_then(|address| address.rsplit(':').next())
+            .and_then(|port_str| port_str.parse().ok());
+
+        // try to get the container's IP address from the ipam config as optional
+        let ip_address: Option<String> = container
+            .network_settings
+            .as_ref()
+            .and_then(|network_settings| {
+            network_settings
+                .networks
+                .as_ref()
+                .and_then(|networks| {
+                networks
+                    .values()
+                    .find(|network| network.ipam_config.is_some())
+                })
+                .and_then(|network| network.ipam_config.as_ref())
+                .and_then(|ipam_config| ipam_config.ipv4_address.clone())
+            })
+            .or_else(|| {
+                warn!(target: "lazymc-docker-proxy::entrypoint::docker", "**************************************************************************************************************************");
+                warn!(target: "lazymc-docker-proxy::entrypoint::docker", "WARNING: You should use IPAM to assign a static IP address to your server container otherwise performance may be degraded.");
+                warn!(target: "lazymc-docker-proxy::entrypoint::docker", "    see: https://github.com/joesturge/lazymc-docker-proxy?tab=readme-ov-file#usage");
+                warn!(target: "lazymc-docker-proxy::entrypoint::docker", "**************************************************************************************************************************");
+                None
+            });
+
+        // if we have a port and an IP address, add the resolved address to the labels
+        if port.is_some() && ip_address.is_some() {
+            let address = format!("{}:{}", ip_address.unwrap(), port.unwrap());
+            debug!(target: "lazymc-docker-proxy::entrypoint::docker", "Resolved address: {}", address);
+            labels.insert("lazymc.server.address".to_string(), address);
+        }
+
         label_sets.push(labels);
     }
 

tests/bats/static-network/docker-compose.yaml

@@ -0,0 +1,47 @@
+version: '3.7'
+
+networks:
+  minecraft-network:
+    driver: bridge    
+    ipam:
+      config:
+        - subnet: 172.21.0.0/16
+
+services:
+  lazymc-static-network:
+    container_name: lazymc-static-network
+    networks:
+      minecraft-network:
+        ipv4_address: 172.21.0.2
+    restart: unless-stopped
+    environment:
+      RUST_LOG: "debug"
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - data:/server:ro
+    ports:
+      - "25565:25565"
+    build: ../../../
+
+  mc-static-network:
+    image: itzg/minecraft-server:java21
+    container_name: mc-static-network
+    networks:
+      minecraft-network:
+        ipv4_address: 172.21.0.3
+    labels:
+      - lazymc.enabled=true
+      - lazymc.group=mc
+      - lazymc.server.address=mc-vanilla:25565
+      - lazymc.time.minimum_online_time=30
+      - lazymc.time.sleep_after=5
+    tty: true
+    stdin_open: true
+    restart: no
+    environment:
+      EULA: "TRUE"
+    volumes:
+      - data:/data
+
+volumes:
+  data:

tests/bats/static-network/static-network.bats

@@ -0,0 +1,50 @@
+#!/usr/bin/env bats
+
+load ../util.bash
+
+project="./tests/bats/static-network"
+
+@test "Static network - Test lazymc resolves the IP address of the minecraft server if using a static network" {
+    # stop the server container
+    stop_container mc-static-network
+
+    # restart the lazymc container
+    restart_container lazymc-static-network
+
+    # reset the start timestamp
+    reset_timestamp
+
+    #
+    # The above steps ensures that this app can read the ip address of a stopped minecraft server
+    #
+
+    # wait for lazymc to replace the address in the config
+    wait_for_formatted_log "lazymc-static-network" "DEBUG" "lazymc-docker-proxy::entrypoint::docker" "Resolved address: 172.21.0.3:25565"
+
+    # wait for the config to generated
+    wait_for_log "lazymc-static-network" "address = \"172.21.0.3:25565\""
+
+        # wait for lazymc process to start
+    wait_for_formatted_log "lazymc-static-network" "INFO" "lazymc-docker-proxy::entrypoint" "Starting lazymc process for group: mc..."
+
+    # wait for lazymc to start the server
+    wait_for_formatted_log "lazymc-static-network" "INFO" "mc::lazymc" "Starting server..."
+
+    # wait for the server to be online
+    wait_for_formatted_log "lazymc-static-network" "INFO" "mc::lazymc::monitor" "Server is now online" 300
+
+    # wait for the mincraft server to be ready
+    wait_for_log "mc-static-network" "RCON running on 0.0.0.0:25575" 300
+
+    # wait for the server to be idle
+    wait_for_formatted_log "lazymc-static-network" "INFO" "mc::lazymc::monitor" "Server has been idle, sleeping..." 120
+
+    # wait for the server to be stopped
+    wait_for_formatted_log "lazymc-static-network" "INFO" "mc::lazymc-docker-proxy::command" "Received SIGTERM, stopping server..."
+
+    # wait for the server to exit
+    wait_for_log "mc-static-network" "Thread RCON Listener stopped"
+
+    # wait for lazymc to sleep
+    wait_for_formatted_log "lazymc-static-network" "INFO" "mc::lazymc::monitor" "Server is now sleeping"
+}

tests/bats/util.bash

@@ -2,9 +2,14 @@
 
 start_timestamp=""
 
+# set up start timestamp
+reset_timestamp() {
+    start_timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+}
+
 # before all tests
 setup() {
-    start_timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+    reset_timestamp
 
     echo "Building docker compose..." >&3
     docker compose --project-directory $project build
@@ -61,4 +66,18 @@ wait_for_log() {
         sleep 1
         ((timeout--))
     done
+}
+
+stop_container() {
+    local container=$1
+
+    echo "Stopping container: $container" >&3
+    docker compose --project-directory $project stop $container
+}
+
+restart_container() {
+    local container=$1
+
+    echo "Restarting container: $container" >&3
+    docker compose --project-directory $project restart $container
 }