Deploy: Add logging and remote session pages

Part of #6

pages/deploy/_meta.json

@@ -2,6 +2,8 @@
   "index": "Introduction",
   "quickstart": "Quick Start",
   "get-started": "Get Started",
+  "usage": "Usage",
   "configuration": "Configuration",
+  "observability": "Observability",
   "cli": "CLI"
 }

pages/deploy/observability/logging.mdx

@@ -0,0 +1,77 @@
+# Logging on Wasmer Edge
+
+Identifying issues in deployed applications often requires log output. 
+
+To make the experience as frictionless as possible, Wasmer Edge automatically
+collects logs from your Webassembly instances and makes them available to you
+through the web interface and the CLI.
+
+## Producing Logs
+
+To produce logs, all you need to do is to emit log output from your application
+to standard output streams.
+
+This means you can use any logging library of your choice in the language you use.
+In Rust [tracing](https://github.com/tokio-rs/tracing) is a popular option.
+
+## Configuring Log Capture
+
+For [proxy - TODO insert proxy deployment link](./) apps, both `stdout` and
+`stderr` are captured by default.
+
+For [WCGI - TODO insert WCGI deployment link](./) apps, only `stderr` is captured,
+because `stdout` is used for transferring the HTTP response.
+
+You will be able to further customize log capturing in the future through the
+app config, to turn off logs or limit them to a specific stream.
+
+This configuration is not available just yet though, so be mindful of which log
+ouput you produce to avoid leaking information.
+
+## Accessing Logs
+
+There are two methods for accessing your logs.
+
+### CLI
+
+The `wasmer app logs` command can retrieve log output.
+
+Some example commands, which assume that your application is called `webserver`:
+
+* Retrieve logs for the last ten minutes:
+
+```bash
+wasmer app logs webserver
+```
+
+* Retrieve logs for a specific time range:
+
+Note the `--max XXX` entry to limit the amount of retrieved log lines.
+
+```bash
+wasmer app logs --max 1000 --from 2023-06-10 --until 2023-06-10T10:00:00
+```
+
+* Retrieve logs in JSON format for further processing:
+
+```bash
+wasmer app logs -f json
+```
+
+### Web Interface
+
+You can access logs through the Wasmer dashboard as well.
+
+Just open the apps dashboard on [wasmer.io/apps](https://wasmer.io/apps) and
+select your app.
+
+![app logs in the Wasmer Dashboard](./logging_webui.png)
+
+## Log Retention and Limits
+
+During the early testing period log retention and log volume limits are subject
+to change.
+
+Different billing tiers will be introduced in the future to allow upgrading to
+longer retention periods and higher log volume limits.
+

pages/deploy/usage/_meta.json

@@ -0,0 +1,3 @@
+{
+  "remote_sessions": "Remote Sessions"
+}

pages/deploy/usage/remoe_sessions.mdx

@@ -0,0 +1,98 @@
+# Remote Sessions
+
+You can start interactive remote sessions on the Wasmer Edge.
+
+A session opens an interactive bash shell, which allows you to run any package
+from the Wasmer registry.
+
+You can even forward ports from the session to your local machine, allowing you
+access to servers running inside the session!
+
+Note that at the moment sessions do not persist after the connection is closed.
+In the future persistent sessions will be introduced. 
+This means you will be able to close the connection and then re-connect to your
+session later on, giving you a persistent remote environment.
+
+While this isn't available quite yet, sessions are already useful to explore the
+ecosystem and to test out the behaviour of your own apps.
+
+## Usage
+
+To start a session:
+* Install the `wasmer` CLI and log in to Wasmer
+  See the [Quickstart](../quickstart/http-server.mdx) for a guide.
+* Make sure the `ssh` command is installed.
+
+Once that is done, you can simply run:
+
+```bash
+wasmer ssh
+````
+
+This will drop you right into a interactive bash session.
+You can now use standard Linux commands like `cd`, `ls`, `mkdir`, ...
+
+You also have access to the `wasmer run` command, so you can run arbitrary
+packages from the Wasmer registry.
+
+For example:
+```bash
+wasmer run john-sharratt/catsay meow
+```
+
+To forward a port, run: 
+
+```bash
+wasmer ssh --map-port 9000
+```
+
+This will forward your local port 9000 to port 9000 in the remote instance,
+allowing you to access remotely running servers.
+
+### Example: Local Access to a Remote Server
+
+We can now combine all these features to run a static web server inside a remote
+session, and access the server locally through a forwarded port.
+
+The below will first start a session with port 9000 mapped.
+We then create a `public` directory and a stub `index.html` file, and start a
+static web server on port 9000.
+
+```bash
+wasmer ssh --map-port 9000
+
+> mkdir public
+> echo HELLO > public/index.html
+> wasmer run wasmer/static-web-server -- -p 9000
+```
+
+You will now be able to access the remote server!
+
+Run this on your local machine in a new terminal window:
+
+```bash
+curl localhost:9000
+
+> HELLO
+````
+
+## How It Works
+
+`wasmer ssh` simply connects to a server in the Wasmer Edge network through a
+standard SSH connection.
+
+The server then runs a command (bash by default), and connects `stdin`, `stdout`
+and `stderr` of the running workload with the SSH session, forwarding all input
+and output.
+
+Port forwarding is also achieved through SSH.
+
+In fact, you could simply replace `wasmer ssh` with `ssh token@WASMER-SERVER-IP`.
+
+The only thing special about `wasmer ssh` is that it will automatically provision
+a token for your user that will be recognized by the Edge servers.
+
+## Billing
+
+Remote sessions will count toward your resource usage on Wasmer, and will be
+included in your invoice.