Adding Redis documentation

docs/connectors/redis.md

@@ -0,0 +1,159 @@
+---
+description: Datero data platform Redis connector. 
+---
+
+# Redis
+This section describes how to connect to Redis in-memory database from Datero.
+
+!!! info "Notice"
+    Used approach is almost identical to the one described in the [Mongo](./mongo.md) section.
+
+## Environment
+If not running, let's start `datero` container created in the [installation](../installation.md#running-the-container) section.
+``` sh
+docker start datero
+```
+
+!!! note "Connectivity pattern"
+    To emulate external host connectivity, we will use [container 2 container](./index.md#container-to-container) approach.
+    We will create `dr` network and connect `datero` container to it.
+    Then we will run datasource `redis` container and connect it to the `dr` network as well.
+
+Now, let's create `dr` network and connect `datero` container to it.
+Also make it resolvable under the `datero` hostname.
+``` sh
+docker network create dr
+docker network connect --alias datero dr datero
+```
+
+To get Redis database we can use official [redis :octicons-tab-external-16:](https://hub.docker.com/_/redis){: target="_blank" rel="noopener noreferrer" } docker image.
+Let's pull the image first.
+``` sh
+docker pull redis
+```
+Now run the container, connect it to the `dr` network and make it resolvable under the `redis_db` hostname.
+We also don't to set any password for database access.
+``` sh
+docker run -d --name redis \
+    --network dr --network-alias redis_db \
+    redis
+```
+Now we can access `redis` container from the `datero` container by its hostname `redis_db`.
+
+
+## Redis database
+Having `redis` container running, we can connect to it and create some test data.
+``` sh
+$ docker exec -it redis redis-cli 
+127.0.0.1:6379> 
+```
+
+Redis is a key-value store.
+Instead of tables and rows it operates by terms of keys and values.
+Key-value creation in Redis is implemented by `SET` command. 
+To setup a "record" like object we could use `HSET` command.
+It sets multiple fields in a hash stored at key.
+
+``` sh
+127.0.0.1:6379> hset furniture:1 id 1 name table
+(integer) 2
+127.0.0.1:6379> hset furniture:2 id 2 name chair
+(integer) 2
+127.0.0.1:6379> hset furniture:3 id 3 name bed
+(integer) 2
+```
+
+To check the data of a specific "record" we could leverage `hgetall` command.
+``` sh
+27.0.0.1:6379> hgetall furniture:1
+1) "id"
+2) "1"
+3) "name"
+4) "table"
+```
+
+Now we are ready to connect to the `redis` database from `datero`.
+
+
+## Datero connection
+Open `Datero` web ui at [http://localhost :octicons-tab-external-16:](http://localhost){: target="_blank" rel="noopener noreferrer" } and click on the `Redis` entry in the the `Connectors` navigation section on the left.
+
+Enter any descriptive name in the `Description` field. For example, `Redis Server`.
+Enter `redis_db` as the `Host` value.
+This is that custom hostname that we specified when were launching `redis` container in the `dr` network.
+This emulates external host connectivity.
+
+In a real-world case, the situation would be similar.
+If you have, for example, Redis running on `redis-host.my-company.com` hostname and
+it's resolvable from the machine where `datero` container is running, you can use that hostname instead.
+
+For the testing purposes we won't set any `Password` value.
+`Port` value is set to the `6379` by default.
+
+Click `Save` to create the Server logical object.
+
+Connector|Connection Form
+:---:|:---:
+![Connectors](../images/connectors/redis/connector.png){ loading=lazy }|![Create Server](../images/connectors/redis/create_server.png){ loading=lazy }
+
+
+## Import table (collection)
+After the Server is created, connection wizard will switch the tab and open `Import Table` form.
+
+!!! note "Import Table"
+    Automatic fetch of the hashes list is under development.
+    Corresponding form is empty for now.
+    User needs to define foreign table manually in the `Query Editor`.
+
+Server Object|Import Schema
+:---:|:---:
+![Server Object](../images/connectors/redis/server_entry.png){ loading=lazy }|![Import Schema](../images/connectors/redis/import_table.png){ loading=lazy }
+
+Because automatic fetching of the collections list is under development, we need to define foreign table manually.
+
+![Servers list](../images/connectors/redis/server_list.png){ loading=lazy; align=right }
+Navigate to the `Query Editor` by clicking on the corresponding icon in the navigation section on the left.
+Get the names of already created server objects via the query.
+``` sql
+select srvname from pg_foreign_server;
+```
+
+`redis_fdw_1` is the internal name of the `Redis Server` object that we created in the previous step.
+We should use it in the `CREATE FOREIGN TABLE` statement.
+
+```sql
+DROP SCHEMA IF EXISTS redis CASCADE;
+CREATE SCHEMA IF NOT EXISTS redis;
+
+CREATE FOREIGN TABLE redis.furniture
+( key       text
+, val       text[]
+) 
+SERVER redis_fdw_1
+OPTIONS (database '0', tabletype 'hash', tablekeyprefix 'furniture:')
+;
+```
+Execute these commands one by one in the editor by pressing `Ctrl+Enter` or clicking green `Run` button above.
+
+
+## Data Querying
+Once table created we could query it.
+```sql
+select * from redis.furniture;
+```
+
+We could also see its structure in the `Query Editor` object navigator.
+
+Foreign Table|Query Data
+:---:|:---:
+![Foreign Table](../images/connectors/redis/foreign_table.png){ loading=lazy }|![Query Data](../images/connectors/redis/query_data.png){ loading=lazy }
+
+And that's it! You have successfully connected to the Redis database from Datero and queried the data.
+
+## Summary
+Of course, having just a single datasource is not very interesting.
+It's non-distinguishable from the direct connection to Redis via any other tool, like DBeaver.
+But the real power of Datero is in its ability to connect to multiple datasources and join data from them.
+
+This is what is not possible via the "direct connection" tools.
+Even if they support connecting to multiple datasources, they don't support joining the data from them.

mkdocs.yml

@@ -110,6 +110,7 @@ nav:
   - MSSQL: connectors/mssql.md
   - SQLite: connectors/sqlite.md
   - File: connectors/file.md
+  - Redis: connectors/redis.md
 - Clouds:
   - clouds/index.md
   - AWS: