20211023 Blynk Server - experimental branch - PR 3 of 3

This PR began with a [Discord question](https://discord.com/channels/638610460567928832/638610461109256194/900627294798893056)
and uncovered a small can of worms.

1. The [github.com/blynkkk/blynk-server](https://github.com/blynkkk/blynk-server)
repository appears to have been deleted. The replacement fork is at
[github.com/Peterkn2001/blynk-server](https://github.com/Peterkn2001/blynk-server).
This requires a change to the Dockerfile.

2. There are several problems with the `directoryfix.sh` mechanism which
are best shown by example:

	* By default, the script lacks execute permission:

		```
		$ cd ~/IOTstack
		$ ls -l ./.templates/blynk_server/directoryfix.sh
		-rw-r--r-- 1 pi pi 2524 Sep  6 11:39 ./.templates/blynk_server/directoryfix.sh
		```

	* Correcting, executing and examining the result:

		```
		$ chmod +x ./.templates/blynk_server/directoryfix.sh
		$ ./.templates/blynk_server/directoryfix.sh
		Sample properties files created in ~/IOTstack/volumes/blynk_server/data/config
		Make sure you edit the files with your details, and restart the container to take effect.
		$ tree ./volumes/blynk_server/
		./volumes/blynk_server/
		└── data
		    └── config
		        ├── mail.properties
		        └── server.properties
		```

	* That folder structure is incorrect. The service definition declares:

		```
		volumes:
		  - ./volumes/blynk_server/data:/data
		  - ./volumes/blynk_server/config:/config
		```

		and the Dockerfile expects `/config` in the `-serverConfig` and
`-mailConfig` arguments:

		```
		ENTRYPOINT ["java", "-jar", "/blynk/server.jar", "-dataFolder", "/data", "-serverConfig", "/config/server.properties", "-mailConfig", "/config/mail.properties"]
		```

	* Thus, a manual fix is needed before the container initialises properly:

		```
		$ sudo mv ./volumes/blynk_server/data/config ./volumes/blynk_server/
		$ tree ./volumes/blynk_server/
		./volumes/blynk_server/
		├── config
		│   ├── mail.properties
		│   └── server.properties
		└── data
		```

	* These problems could be corrected by altering `directoryfix.sh`
but it still leaves the basic problem common to all "directoryFix"
bandaids: the script only runs at menu time, or when the user "just
knows" to run it by hand, and doesn't handle container self-repair
automatically each time the container starts.

3. The existing Dockerfile references `adoptopenjdk/openjdk14` as its
base image. At the time of writing (2021-10-23) the
[DockerHub page](https://hub.docker.com/r/adoptopenjdk/openjdk14)
claims to have been updated 6 months ago but the actual image that
downloads on Raspbian is significantly older:

	```
	$ docker images | grep -e "^REPOSITORY" -e "^adoptopenjdk"
	REPOSITORY                    TAG         IMAGE ID       CREATED         SIZE
	adoptopenjdk/openjdk14        latest      4b3c72387798   15 months ago   403MB
	```

	There is an example Dockerfile at
[github.com/Peterkn2001/blynk-server](https://github.com/Peterkn2001/blynk-server/blob/master/server/Docker/Dockerfile)
which uses `ubuntu` as its base image. This implies that the current
Blynk Server fork is being tested on Ubuntu. It is also clear that
Ubuntu is getting a lot more maintenance:

	```
	$ docker images | grep -e "^REPOSITORY" -e "ubuntu"
	REPOSITORY                    TAG         IMAGE ID       CREATED         SIZE
	ubuntu                        latest      897590a6c564   7 days ago      49.8MB
	```

4. The existing Dockerfile is tightly-coupled with the Blynk-Server
version number. I have abstracted this using an `ARG` statement:

	```
	ARG BLYNK_SERVER_VERSION=0.41.16
	```

	In the Dockerfile, this defaults to the current version but can be
altered by the end user in the compose file:

	```
	  blynk_server:
	    build:
	      context: ./.templates/blynk_server/.
	      args:
	        - BLYNK_SERVER_VERSION=0.41.16
	```

	A user who wants to adopt a later version can alter the compose file
and "build" the container.

5. The blynk server appears to listen to a large number of ports (at
least 587, 7443, 8080, 8081, 8082, 8440, 8441, 8442, 8443 & 9443). Three
ports seem to be directly relevant:

	- 8080 http.port
	- 8440 hardware.mqtt.port
	- 9443 https.port

	Those ports have been:

	- exposed in the Dockerfile, adding 8440 which *is* mentioned in
`server.properties`; and
	- declared in the default service definition, removing 8441 which
is *not* mentioned in `server.properties`.

	Note:

	- The Dockerfile at
[github.com/Peterkn2001/blynk-server](https://github.com/Peterkn2001/blynk-server/blob/master/server/Docker/Dockerfile)
attempts to expose:

		```
		EXPOSE ${HARDWARE_MQTT_PORT} ${HARDWARE_MQTT_PORT_SSL} ${HTTP_PORT} ${HTTPS_PORT}
		```

		`HARDWARE_MQTT_PORT_SSL` is *probably* intended to be port 8441
but it is not actually defined so it evaluates to a null.

6. Container self-repair is implemented in the now fairly
well-established fashion:

	- An `iotstack_defaults` folder in the template is copied into the
image. In this case, it contains the contents of the `config` directory.
	- A `docker-entrypoint.sh` in the template is copied into the image.
When the container is brought up, this script executes first and
performs self-repair, then "execs" the original command over the top.

7. Support for three environment variables:

	- `TZ=Etc/UTC` - the container already has timezone support so this
just makes it clear that it can be activated.
	- `IOTSTACK_UID=1000` & `IOTSTACK_GID=1000` control the ownwership
assigned to the "config" directory and its contents during self-repair.
Defaults to "nobody" if omitted.

8. Documentation not changed.

Author: Paraphraser

.internal/templates/services/blynk_server/buildFiles/Dockerfile

@@ -1,20 +1,75 @@
-FROM adoptopenjdk/openjdk14
-MAINTAINER 877dev <[email protected]>
+# Acknowledgements:
+#   Based on:
+#    https://github.com/SensorsIot/IOTstack/blob/master/.templates/blynk_server/Dockerfile
+#      (as at commit ID 4dff89c1bb6a5b1c01d3c087dcb662256a0c050f)
+#   Borrows from:
+#    https://github.com/Peterkn2001/blynk-server/blob/master/server/Docker/Dockerfile
+#      (as at commit ID 889c7e55161832e21264d993d9fa5abd1c015e1c)
 
-#RUN apt-get update
-#RUN apt-get install -y apt-utils
-#RUN apt-get install -y default-jdk curl
+FROM ubuntu
 
-ENV BLYNK_SERVER_VERSION 0.41.16
-RUN mkdir /blynk
-RUN curl -L https://github.com/blynkkk/blynk-server/releases/download/v${BLYNK_SERVER_VERSION}/server-${BLYNK_SERVER_VERSION}.jar > /blynk/server.jar
+# declare the version to be built, defaulting to 0.41.16 (which is
+# current as of 2021-10-22)
+ARG BLYNK_SERVER_VERSION=0.41.16
 
-# Create data folder. To persist data, map a volume to /data
-RUN mkdir /data
+# form the download URL
+ENV BLYNK_SERVER_URL=https://github.com/Peterkn2001/blynk-server/releases/download/v${BLYNK_SERVER_VERSION}/server-${BLYNK_SERVER_VERSION}.jar
 
-# Create configuration folder. To persist data, map a file to /config/server.properties
-RUN mkdir /config && touch /config/server.properties
-VOLUME ["/config", "/data/backup"]
+# Add support packages to the base image
+RUN apt-get update \
+ && apt-get install -y \
+      apt-utils \
+      libreadline8 \
+      libreadline-dev \
+ && apt-get install -y \
+      curl \
+      libxrender1 \
+      maven \
+      openjdk-11-jdk \
+      rsync
 
-WORKDIR /data
-ENTRYPOINT ["java", "-jar", "/blynk/server.jar", "-dataFolder", "/data", "-serverConfig", "/config/server.properties", "-mailConfig", "/config/mail.properties"]
+# Add IOTstack-specific support
+ENV IOTSTACK_DEFAULTS_DIR="iotstack_defaults"
+ENV IOTSTACK_ENTRY_POINT="docker-entrypoint.sh"
+COPY ${IOTSTACK_DEFAULTS_DIR} /${IOTSTACK_DEFAULTS_DIR}
+COPY ${IOTSTACK_ENTRY_POINT} /${IOTSTACK_ENTRY_POINT}
+RUN chmod 755 /${IOTSTACK_ENTRY_POINT}
+
+# define well-known paths
+ENV IOTSTACK_DATA_DIR="/data"
+ENV IOTSTACK_CONF_DIR="/config"
+ENV IOTSTACK_JAVA_DIR="/blynk"
+
+# Create and populate expected folders
+RUN mkdir -p ${IOTSTACK_DATA_DIR} ${IOTSTACK_JAVA_DIR} \
+ && curl -L ${BLYNK_SERVER_URL} >"${IOTSTACK_JAVA_DIR}/server.jar"
+
+# declare expected mapped volumes
+VOLUME ["${IOTSTACK_CONF_DIR}", "${IOTSTACK_DATA_DIR}"]
+
+# Expose assumed internal ports:
+#   8080 http.port
+#   8440 hardware.mqtt.port
+#   9443 https.port
+EXPOSE 8080 8440 9443
+
+# set the working directory
+WORKDIR ${IOTSTACK_DATA_DIR}
+
+# define launch procedure
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["java", "-jar", "/blynk/server.jar", "-dataFolder", "/data", "-serverConfig", "/config/server.properties", "-mailConfig", "/config/mail.properties"]
+
+# supplement image metadata
+LABEL blynk-server.version=${BLYNK_SERVER_VERSION}
+LABEL blynk-server.url=${BLYNK_SERVER_URL}
+LABEL com.github.SensorsIot.IOTstack.Dockerfile.maintainer="877dev <[email protected]>"
+LABEL com.github.Peterkn2001.blynk-server.Dockerfile.maintainer="Florian Mauduit <[email protected]>"
+
+# unset variables that are not needed by docker-entrypoint.sh
+ENV IOTSTACK_ENTRY_POINT=
+ENV IOTSTACK_DATA_DIR=
+ENV IOTSTACK_JAVA_DIR=
+ENV BLYNK_SERVER_URL=
+
+# EOF

.internal/templates/services/blynk_server/buildFiles/docker-entrypoint.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -e
+
+# were we launched as root with defaults available?
+if [ "$(id -u)" = "0" -a -d /"$IOTSTACK_DEFAULTS_DIR" ]; then
+
+   # yes! ensure that the IOTSTACK_CONF_DIR exists
+   mkdir -p "$IOTSTACK_CONF_DIR"
+
+   # populate runtime directory from the defaults
+   rsync -arp --ignore-existing "/${IOTSTACK_DEFAULTS_DIR}/" "${IOTSTACK_CONF_DIR}"
+
+   # enforce correct ownership
+   chown -R "${IOTSTACK_UID:-nobody}":"${IOTSTACK_GID:-nobody}" "$IOTSTACK_CONF_DIR"
+
+fi
+
+# start the blynk server
+exec "$@"

.internal/templates/services/blynk_server/buildFiles/iotstack_defaults/mail.properties

@@ -0,0 +1,9 @@
+mail.smtp.auth=true
+    mail.smtp.starttls.enable=true
+    mail.smtp.host=smtp.gmail.com
+    mail.smtp.port=587
+    mail.smtp.username[email protected]
+    mail.smtp.password=YOUR_GMAIL_APP_PASSWORD
+    mail.smtp.connectiontimeout=30000
+    mail.smtp.timeout=120000
+    

.internal/templates/services/blynk_server/buildFiles/iotstack_defaults/server.properties

@@ -0,0 +1,40 @@
+hardware.mqtt.port=8440
+    http.port=8080
+    force.port.80.for.csv=false
+    force.port.80.for.redirect=true
+    https.port=9443
+    data.folder=./data
+    logs.folder=./logs
+    log.level=info
+    user.devices.limit=10
+    user.tags.limit=100
+    user.dashboard.max.limit=100
+    user.widget.max.size.limit=20
+    user.message.quota.limit=100
+    notifications.queue.limit=2000
+    blocking.processor.thread.pool.limit=6
+    notifications.frequency.user.quota.limit=5
+    webhooks.frequency.user.quota.limit=1000
+    webhooks.response.size.limit=96
+    user.profile.max.size=128
+    terminal.strings.pool.size=25
+    map.strings.pool.size=25
+    lcd.strings.pool.size=6
+    table.rows.pool.size=100
+    profile.save.worker.period=60000
+    stats.print.worker.period=60000
+    web.request.max.size=524288
+    csv.export.data.points.max=43200
+    hard.socket.idle.timeout=10
+    enable.db=false
+    enable.raw.db.data.store=false
+    async.logger.ring.buffer.size=2048
+    allow.reading.widget.without.active.app=false
+    allow.store.ip=true
+    initial.energy=1000000
+    admin.rootPath=/admin
+    restore.host=blynk-cloud.com
+    product.name=Blynk
+    admin.email[email protected]
+    admin.pass=admin
+    

.internal/templates/services/blynk_server/directoryfix.sh

@@ -1,14 +1,20 @@
 blynk_server:
-  build: ./services/blynk_server/.
+  build:
+    context: ./.templates/blynk_server/.
+    args:
+      - BLYNK_SERVER_VERSION=0.41.16
   container_name: blynk_server
   restart: unless-stopped
+  environment:
+    - TZ=Etc/UTC
+    - IOTSTACK_UID=1000
+    - IOTSTACK_GID=1000
   ports:
     - "8180:8080"
-    - "8441:8441"
+    - "8440:8440"
     - "9443:9443"
   volumes:
     - ./volumes/blynk_server/data:/data
     - ./volumes/blynk_server/config:/config
   networks:
     - iotstack_nw
-