synapse/docker/README.md

Synapse Docker

This Docker image will run Synapse as a single process. By default it uses a sqlite database; for production use you should connect it to a separate postgres database.

The image also does not provide a TURN server.

Run

Using docker-compose (easier)

This image is designed to run either with an automatically generated configuration file or with a custom configuration that requires manual editing.

An easy way to make use of this image is via docker-compose. See the contrib/docker section of the synapse project for examples.

Without Compose (harder)

If you do not wish to use Compose, you may still run this image using plain Docker commands. Note that the following is just a guideline and you may need to add parameters to the docker run command to account for the network situation with your postgres database.

docker run \
    -d \
    --name synapse \
    --mount type=volume,src=synapse-data,dst=/data \
    -e SYNAPSE_SERVER_NAME=my.matrix.host \
    -e SYNAPSE_REPORT_STATS=yes \
    -p 8448:8448 \
    matrixdotorg/synapse:latest

Volumes

The image expects a single volume, located at /data, that will hold:

• temporary files during uploads;
• uploaded media and thumbnails;
• the SQLite database if you do not configure postgres;
• the appservices configuration.

You are free to use separate volumes depending on storage endpoints at your disposal. For instance, /data/media coud be stored on a large but low performance hdd storage while other files could be stored on high performance endpoints.

In order to setup an application service, simply create an appservices directory in the data volume and write the application service Yaml configuration file there. Multiple application services are supported.

TLS certificates

Synapse requires a valid TLS certificate. You can do one of the following:

• Provide your own certificate and key (as ${DATA_PATH}/${SYNAPSE_SERVER_NAME}.tls.crt and ${DATA_PATH}/${SYNAPSE_SERVER_NAME}.tls.key, or elsewhere by providing an entire config as ${SYNAPSE_CONFIG_PATH}). In this case, you should forward traffic to port 8448 in the container, for example with -p 443:8448.

• Use a reverse proxy to terminate incoming TLS, and forward the plain http traffic to port 8008 in the container. In this case you should set -e SYNAPSE_NO_TLS=1.

• Use the ACME (Let's Encrypt) support built into Synapse. This requires ${SYNAPSE_SERVER_NAME} port 80 to be forwarded to port 8009 in the container, for example with -p 80:8009. To enable it in the docker container, set -e SYNAPSE_ACME=1.

If you don't do any of these, Synapse will fail to start with an error similar to:

synapse.config._base.ConfigError: Error accessing file '/data/<server_name>.tls.crt' (config for tls_certificate): No such file or directory

Environment

Unless you specify a custom path for the configuration file, a very generic file will be generated, based on the following environment settings. These are a good starting point for setting up your own deployment.

Global settings:

• UID, the user id Synapse will run as [default 991]
• GID, the group id Synapse will run as [default 991]
• SYNAPSE_CONFIG_PATH, path to a custom config file

If SYNAPSE_CONFIG_PATH is set, you should generate a configuration file then customize it manually: see Generating a config file.

Otherwise, a dynamic configuration file will be used.

Environment variables used to build a dynamic configuration file

The following environment variables are used to build the configuration file when SYNAPSE_CONFIG_PATH is not set.

• SYNAPSE_SERVER_NAME (mandatory), the server public hostname.
• SYNAPSE_REPORT_STATS, (mandatory, yes or no), enable anonymous statistics reporting back to the Matrix project which helps us to get funding.
• SYNAPSE_NO_TLS, (accepts true, false, on, off, 1, 0, yes, no]): disable TLS in Synapse (use this if you run your own TLS-capable reverse proxy). Defaults to false (ie, TLS is enabled by default).
• SYNAPSE_ENABLE_REGISTRATION, set this variable to enable registration on the Synapse instance.
• SYNAPSE_ALLOW_GUEST, set this variable to allow guest joining this server.
• SYNAPSE_EVENT_CACHE_SIZE, the event cache size [default 10K].
• SYNAPSE_RECAPTCHA_PUBLIC_KEY, set this variable to the recaptcha public key in order to enable recaptcha upon registration.
• SYNAPSE_RECAPTCHA_PRIVATE_KEY, set this variable to the recaptcha private key in order to enable recaptcha upon registration.
• SYNAPSE_TURN_URIS, set this variable to the coma-separated list of TURN uris to enable TURN for this homeserver.
• SYNAPSE_TURN_SECRET, set this to the TURN shared secret if required.
• SYNAPSE_MAX_UPLOAD_SIZE, set this variable to change the max upload size [default 10M].
• SYNAPSE_ACME: set this to enable the ACME certificate renewal support.

Shared secrets, that will be initialized to random values if not set:

• SYNAPSE_REGISTRATION_SHARED_SECRET, secret for registrering users if registration is disable.
• SYNAPSE_MACAROON_SECRET_KEY secret for signing access tokens to the server.

Database specific values (will use SQLite if not set):

• POSTGRES_DB - The database name for the synapse postgres database. [default: synapse]
• POSTGRES_HOST - The host of the postgres database if you wish to use postgresql instead of sqlite3. [default: db which is useful when using a container on the same docker network in a compose file where the postgres service is called db]
• POSTGRES_PASSWORD - The password for the synapse postgres database. If this is set then postgres will be used instead of sqlite3. [default: none] NOTE: You are highly encouraged to use postgresql! Please use the compose file to make it easier to deploy.
• POSTGRES_USER - The user for the synapse postgres database. [default: synapse]

Mail server specific values (will not send emails if not set):

• SYNAPSE_SMTP_HOST, hostname to the mail server.
• SYNAPSE_SMTP_PORT, TCP port for accessing the mail server [default 25].
• SYNAPSE_SMTP_USER, username for authenticating against the mail server if any.
• SYNAPSE_SMTP_PASSWORD, password for authenticating against the mail server if any.

Generating a config file

It is possible to generate a basic configuration file for use with SYNAPSE_CONFIG_PATH using the generate commandline option. You will need to specify values for SYNAPSE_CONFIG_PATH, SYNAPSE_SERVER_NAME and SYNAPSE_REPORT_STATS, and mount a docker volume to store the data on. For example:

docker run -it --rm
    --mount type=volume,src=synapse-data,dst=/data \
    -e SYNAPSE_CONFIG_PATH=/data/homeserver.yaml \
    -e SYNAPSE_SERVER_NAME=my.matrix.host \
    -e SYNAPSE_REPORT_STATS=yes \
    matrixdotorg/synapse:latest generate

This will generate a homeserver.yaml in (typically) /var/lib/docker/volumes/synapse-data/_data, which you can then customise and use with:

docker run -d --name synapse \
    --mount type=volume,src=synapse-data,dst=/data \
    -e SYNAPSE_CONFIG_PATH=/data/homeserver.yaml \
    matrixdotorg/synapse:latest