Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/secretstores/docker/README.md

@@ -0,0 +1,93 @@
+# Docker Secrets Secret-Store Plugin
+
+The `docker` plugin allows to utilize credentials and secrets mounted by
+Docker during container runtime. The secrets are mounted as files
+under the `/run/secrets` directory within the container.
+
+> NOTE: This plugin can ONLY read the mounted secrets from Docker and NOT set them.
+
+## Usage <!-- @/docs/includes/secret_usage.md -->
+
+Secrets defined by a store are referenced with `@{<store-id>:<secret_key>}`
+the Telegraf configuration. Only certain Telegraf plugins and options of
+support secret stores. To see which plugins and options support
+secrets, see their respective documentation (e.g.
+`plugins/outputs/influxdb/README.md`). If the plugin's README has the
+`Secret-store support` section, it will detail which options support secret
+store usage.
+
+## Configuration
+
+```toml @sample.conf
+# Secret-store to access Docker Secrets
+[[secretstores.docker]]
+  ## Unique identifier for the secretstore.
+  ## This id can later be used in plugins to reference the secrets
+  ## in this secret-store via @{<id>:<secret_key>} (mandatory)
+  id = "docker_secretstore"
+
+  ## Default Path to directory where docker stores the secrets file
+  ## Current implementation in docker compose v2 only allows the following
+  ## value for the path where the secrets are mounted at runtime
+  # path = "/run/secrets"
+
+  ## Allow dynamic secrets that are updated during runtime of telegraf
+  ## Dynamic Secrets work only with `file` or `external` configuration
+  ## in `secrets` section of the `docker-compose.yml` file
+  # dynamic = false
+```
+
+Each Secret mentioned within a Compose service's `secrets` parameter will be
+available as file under the `/run/secrets/<secret-name>` within the container.
+
+It is possible to let Telegraf pick changed secret values into plugins by setting
+`dynamic = true`. This feature will work only for Docker Secrets provided via
+`file` and `external` type within the `docker-compose.yml` file
+and not when using `environment` type
+(Refer here [Docker Secrets in Compose Specification][1]).
+
+## Example Compose File
+
+```yaml
+services:
+  telegraf:
+    image: docker.io/telegraf:latest
+    container_name: dockersecret_telegraf
+    user: "${USERID}" # Required to access the /run/secrets directory in container
+    secrets:
+      - secret_for_plugin
+    volumes:
+      - /path/to/telegrafconf/host:/etc/telegraf/telegraf.conf:ro
+
+secrets:
+  secret_for_plugin:
+    environment: TELEGRAF_PLUGIN_CREDENTIAL
+```
+
+here the `TELEGRAF_PLUGIN_CREDENTIAL` exists in a `.env` file in the same directory
+as the `docker-compose.yml`. An example of the `.env` file can be as follows:
+
+```env
+TELEGRAF_PLUGIN_CREDENTIAL=superSecretStuff
+# determine this value by executing `id -u` in terminal
+USERID=1000
+```
+
+### Referencing Secret within a Plugin
+
+Referencing the secret within a plugin occurs by:
+
+```toml
+[[inputs.<some_plugin>]]
+  password = "@{docker_secretstore:secret_for_plugin}"
+```
+
+## Additional Information
+
+[Docker Secrets in Swarm][2]
+
+[Creating Secrets in Docker][3]
+
+[1]: https://github.com/compose-spec/compose-spec/blob/master/09-secrets.md
+[2]: https://docs.docker.com/engine/swarm/secrets/
+[3]: https://www.rockyourcode.com/using-docker-secrets-with-docker-compose/