Introduce volume configuration for floki

This introduces configuration parsing for volumes in floki.

Currently the configuration isn't interpreted, so no volumes are actually added to the running floki container.
However this provides the intended configuration semantics.

Volumes can be configured in `floki.yaml` under the `volumes` key:

```
volumes:
  cargo-registry:
    shared: true
    mount: /home/rust/.cargo/registry
  something-else:
    mount: /something
```

Intended interpretation
-----------------------

The `shared` key indicates that this volume should be shared across all containers using
the same key (with `shared` also set). Setting `shared` may be elided, in which case it
defaults to false, and the volume will only be used by containers using the same `floki.yaml`
configuration files.

Signed-off-by: Richard Lupton <[email protected]>

src/config.rs

@@ -4,32 +4,40 @@ use crate::image;
 use failure::Error;
 use quicli::prelude::*;
 
+use std::collections::BTreeMap;
 use std::fs::File;
 use std::path;
 
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[serde(untagged)]
-pub enum Shell {
+pub(crate) enum Shell {
     Shell(String),
     TwoShell { inner: String, outer: String },
 }
 
 impl Shell {
-    pub fn inner_shell(&self) -> &str {
+    pub(crate) fn inner_shell(&self) -> &str {
         match self {
             Shell::Shell(s) => s,
             Shell::TwoShell { inner: s, outer: _ } => s,
         }
     }
 
-    pub fn outer_shell(&self) -> &str {
+    pub(crate) fn outer_shell(&self) -> &str {
         match self {
             Shell::Shell(s) => s,
             Shell::TwoShell { inner: _, outer: s } => s,
         }
     }
 }
 
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+pub(crate) struct Volume {
+    #[serde(default = "default_to_false")]
+    shared: bool,
+    mount: path::PathBuf,
+}
+
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub(crate) struct FlokiConfig {
@@ -48,6 +56,8 @@ pub(crate) struct FlokiConfig {
     pub(crate) dind: bool,
     #[serde(default = "default_to_false")]
     pub(crate) forward_user: bool,
+    #[serde(default = "BTreeMap::new")]
+    pub(crate) volumes: BTreeMap<String, Volume>,
 }
 
 impl FlokiConfig {
@@ -83,6 +93,12 @@ impl FlokiConfig {
             }
         }
 
+        debug!(
+            "Parsed '{}' into configuration: {:?}",
+            file.display(),
+            &config
+        );
+
         Ok(config)
     }
 }

src/verify.rs

@@ -16,6 +16,8 @@ mod test {
     use crate::config::Shell::Shell;
     use crate::image::Image::Name;
 
+    use std::collections::BTreeMap;
+
     fn get_test_config(docker_switches: Vec<String>) -> FlokiConfig {
         FlokiConfig {
             image: Name("foo".into()),
@@ -26,6 +28,7 @@ mod test {
             forward_ssh_agent: false,
             dind: false,
             forward_user: false,
+            volumes: BTreeMap::new(),
         }
     }