snapshots: Prepare for restructuring

This commit renames the 'wisski' package to 'dis' and prepares the
snapshots component for restructuring.

internal/dis/init.go

@@ -0,0 +1,70 @@
+package dis
+
+import (
+	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/config"
+	"github.com/FAU-CDI/wisski-distillery/internal/core"
+	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
+	"github.com/tkw1536/goprogram/exit"
+)
+
+var errNoConfigFile = exit.Error{
+	ExitCode: exit.ExitGeneralArguments,
+	Message:  "Configuration File does not exist",
+}
+
+var errOpenConfig = exit.Error{
+	ExitCode: exit.ExitGeneralArguments,
+	Message:  "error loading configuration file: %s",
+}
+
+// NewDistillery creates a new distillery from the provided flags
+func NewDistillery(params core.Params, flags core.Flags, req core.Requirements) (dis *Distillery, err error) {
+	dis = &Distillery{
+		Core: component.Core{
+			Environment: environment.Native{},
+		},
+		Upstream: Upstream{
+			SQL:         "127.0.0.1:3306",
+			Triplestore: "127.0.0.1:7200",
+		},
+	}
+
+	// we are within the docker
+	//
+	// so setup the ports to connect everything to peroperly.
+	// also override some of the parameters for the environment.
+	if flags.InternalInDocker {
+		dis.Upstream.SQL = "sql:3306"
+		dis.Upstream.Triplestore = "triplestore:7200"
+		params.ConfigPath = dis.Core.Environment.GetEnv("CONFIG_PATH")
+	}
+
+	// if we don't need to load the config, there is nothing to do
+	if !req.NeedsDistillery {
+		return
+	}
+
+	// try to find the configuration file
+	cfg := flags.ConfigPath // command line flags first
+	if cfg == "" {
+		cfg = params.ConfigPath // then globally provided files
+	}
+	if cfg == "" {
+		return nil, errNoConfigFile
+	}
+
+	// open the config file!
+	f, err := dis.Core.Environment.Open(params.ConfigPath)
+	if err != nil {
+		return nil, errOpenConfig.WithMessageF(err)
+	}
+	defer f.Close()
+
+	// unmarshal the config
+	dis.Config = &config.Config{
+		ConfigPath: cfg,
+	}
+	err = dis.Config.Unmarshal(dis.Core.Environment, f)
+	return
+}