Log env var before merge on Combine

Also, add debug configuration & example for Combine

Author: kylos101

.vscode/launch.json

@@ -18,6 +18,23 @@
                 "."
             ]
         },
+        {
+            "name": "Dazzle example combine",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${fileWorkspaceFolder}",
+            "args": [
+                "combine",
+                "--addr",
+                "unix:///run/buildkit/buildkitd.sock",
+                "--context",
+                "example",
+                "localhost:5000/dazzle",
+                "--all",
+                "."
+            ]
+        },
         {
             "name": "Dazzle runner",
             "type": "go",

example.sh

@@ -2,4 +2,5 @@
 
 # Build and run the example
 gp await-port 5000
-go run main.go build --context example localhost:5000/dazzle
+go run main.go build --context example localhost:5000/dazzle
+go run main.go combine --context example localhost:5000/dazzle --all

pkg/dazzle/build.go

@@ -170,7 +170,7 @@ func (p *Project) Build(ctx context.Context, session *BuildSession) error {
 	for _, chk := range p.Chunks {
 		_, _, err := chk.test(ctx, session)
 		if err != nil {
-			return fmt.Errorf("cannot build chunk %s: %w", chk.Name, err)
+			return fmt.Errorf("cannot test chunk %s: %w", chk.Name, err)
 		}
 
 		_, _, err = chk.build(ctx, session)

pkg/dazzle/combiner.go

@@ -286,15 +286,15 @@ func mergeEnv(base *ociv1.Image, others []*ociv1.Image, vars []EnvVarCombination
 		envs[segs[0]] = segs[1]
 	}
 
-	for _, m := range others {
-		for _, e := range m.Config.Env {
-			segs := strings.Split(e, "=")
+	for _, ociImage := range others {
+		for _, imageEnvVars := range ociImage.Config.Env {
+			segs := strings.Split(imageEnvVars, "=")
 			if len(segs) != 2 {
-				return nil, fmt.Errorf("env var %s in invalid", e)
+				return nil, fmt.Errorf("env var %s in invalid", imageEnvVars)
 			}
 
 			k, v := segs[0], segs[1]
-			if ov, exists := envs[k]; exists {
+			if envValue, exists := envs[k]; exists {
 				action := EnvVarCombineUseFirst
 				for _, mv := range vars {
 					if mv.Name == k {
@@ -312,7 +312,7 @@ func mergeEnv(base *ociv1.Image, others []*ociv1.Image, vars []EnvVarCombination
 					envs[k] += ":" + v
 				case EnvVarCombineMergeUnique:
 					vs := make(map[string]struct{})
-					for _, s := range strings.Split(ov, ":") {
+					for _, s := range strings.Split(envValue, ":") {
 						vs[s] = struct{}{}
 					}
 					vs[v] = struct{}{}
@@ -323,9 +323,10 @@ func mergeEnv(base *ociv1.Image, others []*ociv1.Image, vars []EnvVarCombination
 					envs[k] = strings.Join(vss, ":")
 				}
 				log.WithFields(log.Fields{
-					"action":    action,
-					"name":      k,
-					"new-value": envs[k],
+					"action":     action,
+					"name":       k,
+					"image-vars": envValue,
+					"new-value":  envs[k],
 				}).Info("merged environment variable")
 
 				continue