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refactor(context): Implement more explicit merging of variables

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The hierarchy for loading variables was previously not expressed
explicitly.

This commit refactors the logic for merging variables to explicitly
set the different layers of variables as values on the context object
and merge them for each resource set in `mergeContextValues`.
This commit is contained in:
Vincent Ambo 2018-06-09 16:23:09 +02:00 committed by Vincent Ambo
parent 5cf9d53e80
commit b33c353233
5 changed files with 96 additions and 62 deletions
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86
context/context.go
View file

@ -43,11 +43,17 @@ type Context struct {
Global map[string]interface{} `json:"global"`
// File names of YAML or JSON files including extra variables that should be globally accessible
VariableImports []string `json:"import"`
VariableImportFiles []string `json:"import"`
// The resource sets to include in this context
ResourceSets []ResourceSet `json:"include"`
// Variables imported from additional files
ImportedVars map[string]interface{}
// Explicitly set variables (via `--var`) that should override all others
ExplicitVars map[string]interface{}
// This field represents the absolute path to the context base directory and should not be manually specified.
BaseDir string
}
@ -57,41 +63,59 @@ func contextLoadingError(filename string, cause error) error {
}
// Attempt to load and deserialise a Context from the specified file.
func LoadContextFromFile(filename string) (*Context, error) {
var c Context
err := util.LoadJsonOrYaml(filename, &c)
func LoadContext(filename string, explicitVars *[]string) (*Context, error) {
var ctx Context
err := util.LoadJsonOrYaml(filename, &ctx)
if err != nil {
return nil, contextLoadingError(filename, err)
}
c.ResourceSets = flattenPrepareResourceSetPaths(&c.ResourceSets)
c.BaseDir = path.Dir(filename)
c.ResourceSets = loadAllDefaultValues(&c)
ctx.BaseDir = path.Dir(filename)
err = c.loadImportedVariables()
// Prepare the resource sets by resolving parents etc.
ctx.ResourceSets = flattenPrepareResourceSetPaths(&ctx.ResourceSets)
// Add variables explicitly specified on the command line
ctx.ExplicitVars, err = loadExplicitVars(explicitVars)
if err != nil {
return nil, fmt.Errorf("Error setting explicit variables: %v\n", err)
}
// Add variables loaded from import files
ctx.ImportedVars, err = ctx.loadImportedVariables()
if err != nil {
return nil, contextLoadingError(filename, err)
}
return &c, nil
// Merge variables (explicit > import > include > global > default)
ctx.ResourceSets = ctx.mergeContextValues()
if err != nil {
return nil, contextLoadingError(filename, err)
}
return &ctx, nil
}
// Kontemplate supports specifying additional variable files with the `import` keyword. This function loads those
// variable files and merges them together with the context's other global variables.
func (ctx *Context) loadImportedVariables() error {
for _, file := range ctx.VariableImports {
// Kontemplate supports specifying additional variable files with the
// `import` keyword. This function loads those variable files and
// merges them together with the context's other global variables.
func (ctx *Context) loadImportedVariables() (map[string]interface{}, error) {
allImportedVars := make(map[string]interface{})
for _, file := range ctx.VariableImportFiles {
var importedVars map[string]interface{}
err := util.LoadJsonOrYaml(path.Join(ctx.BaseDir, file), &importedVars)
if err != nil {
return err
return nil, err
}
ctx.Global = *util.Merge(&ctx.Global, &importedVars)
allImportedVars = *util.Merge(&allImportedVars, &importedVars)
}
return nil
return allImportedVars, nil
}
// Correctly prepares the file paths for resource sets by inferring implicit paths and flattening resource set
@ -128,11 +152,16 @@ func flattenPrepareResourceSetPaths(rs *[]ResourceSet) []ResourceSet {
return flattened
}
func loadAllDefaultValues(c *Context) []ResourceSet {
updated := make([]ResourceSet, len(c.ResourceSets))
// Merges the context and resource set variables according in the
// desired precedence order.
func (ctx *Context) mergeContextValues() []ResourceSet {
updated := make([]ResourceSet, len(ctx.ResourceSets))
for i, rs := range c.ResourceSets {
merged := loadDefaultValues(&rs, c)
for i, rs := range ctx.ResourceSets {
merged := loadDefaultValues(&rs, ctx)
merged = util.Merge(&ctx.Global, merged)
merged = util.Merge(merged, &ctx.ImportedVars)
merged = util.Merge(merged, &ctx.ExplicitVars)
rs.Values = *merged
updated[i] = rs
}
@ -160,22 +189,19 @@ func loadDefaultValues(rs *ResourceSet, c *Context) *map[string]interface{} {
return &rs.Values
}
// New variables can be defined or default values overridden with command line arguments when executing kontemplate.
func (ctx *Context) SetVariablesFromArguments(vars *[]string) error {
// Resource set files might not have defined any global variables, if so we have to
// create that a map before potentially writing variables into it
if ctx.Global == nil {
ctx.Global = make(map[string]interface{}, len(*vars))
}
// Prepares the variables specified explicitly via `--var` when
// executing kontemplate for adding to the context.
func loadExplicitVars(vars *[]string) (map[string]interface{}, error) {
explicitVars := make(map[string]interface{}, len(*vars))
for _, v := range *vars {
varParts := strings.Split(v, "=")
if len(varParts) != 2 {
return fmt.Errorf(`invalid explicit variable provided (%s), name and value should be divided with "="`, v)
return nil, fmt.Errorf(`invalid explicit variable provided (%s), name and value should be separated with "="`, v)
}
ctx.Global[varParts[0]] = varParts[1]
explicitVars[varParts[0]] = varParts[1]
}
return nil
return explicitVars, nil
}

60
context/context_test.go
View file

@ -14,8 +14,10 @@ import (
"testing"
)
var noExplicitVars []string = make([]string, 0)
func TestLoadFlatContextFromFile(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/flat-test.yaml")
ctx, err := LoadContext("testdata/flat-test.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
@ -35,12 +37,15 @@ func TestLoadFlatContextFromFile(t *testing.T) {
"apiPort": float64(4567), // yep!
"importantFeature": true,
"version": "1.0-0e6884d",
"globalVar": "lizards",
},
Include: nil,
Parent: "",
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -50,7 +55,7 @@ func TestLoadFlatContextFromFile(t *testing.T) {
}
func TestLoadContextWithResourceSetCollections(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/collections-test.yaml")
ctx, err := LoadContext("testdata/collections-test.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
@ -70,6 +75,7 @@ func TestLoadContextWithResourceSetCollections(t *testing.T) {
"apiPort": float64(4567), // yep!
"importantFeature": true,
"version": "1.0-0e6884d",
"globalVar": "lizards",
},
Include: nil,
Parent: "",
@ -79,12 +85,15 @@ func TestLoadContextWithResourceSetCollections(t *testing.T) {
Path: "collection/nested",
Values: map[string]interface{}{
"lizards": "good",
"globalVar": "lizards",
},
Include: nil,
Parent: "collection",
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -95,7 +104,7 @@ func TestLoadContextWithResourceSetCollections(t *testing.T) {
}
func TestSubresourceVariableInheritance(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/parent-variables.yaml")
ctx, err := LoadContext("testdata/parent-variables.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
@ -117,6 +126,8 @@ func TestSubresourceVariableInheritance(t *testing.T) {
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -126,7 +137,7 @@ func TestSubresourceVariableInheritance(t *testing.T) {
}
func TestSubresourceVariableInheritanceOverride(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/parent-variable-override.yaml")
ctx, err := LoadContext("testdata/parent-variable-override.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
@ -147,6 +158,8 @@ func TestSubresourceVariableInheritanceOverride(t *testing.T) {
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -156,7 +169,7 @@ func TestSubresourceVariableInheritanceOverride(t *testing.T) {
}
func TestDefaultValuesLoading(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/default-loading.yaml")
ctx, err := LoadContext("testdata/default-loading.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
t.Fail()
@ -175,7 +188,7 @@ func TestDefaultValuesLoading(t *testing.T) {
}
func TestImportValuesLoading(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/import-vars-simple.yaml")
ctx, err := LoadContext("testdata/import-vars-simple.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
t.Fail()
@ -189,14 +202,14 @@ func TestImportValuesLoading(t *testing.T) {
},
}
if !reflect.DeepEqual(ctx.Global, expected) {
t.Error("Expected global values after loading imports did not match!")
if !reflect.DeepEqual(ctx.ImportedVars, expected) {
t.Error("Expected imported values after loading imports did not match!")
t.Fail()
}
}
func TestImportValuesOverride(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/import-vars-override.yaml")
func TestValuesOverride(t *testing.T) {
ctx, err := LoadContext("testdata/import-vars-override.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
t.Fail()
@ -208,18 +221,18 @@ func TestImportValuesOverride(t *testing.T) {
"artist": "Pallida",
"track": "Tractor Beam",
},
"place": "Oslo",
"place": "Oslo",
"globalVar": "very global!",
}
if !reflect.DeepEqual(ctx.Global, expected) {
t.Error("Expected global values after loading imports did not match!")
if !reflect.DeepEqual(ctx.ResourceSets[0].Values, expected) {
t.Error("Expected overrides after loading imports did not match!")
t.Fail()
}
}
func TestExplicitPathLoading(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/explicit-path.yaml")
ctx, err := LoadContext("testdata/explicit-path.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
t.Fail()
@ -248,6 +261,8 @@ func TestExplicitPathLoading(t *testing.T) {
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -257,7 +272,7 @@ func TestExplicitPathLoading(t *testing.T) {
}
func TestExplicitSubresourcePathLoading(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/explicit-subresource-path.yaml")
ctx, err := LoadContext("testdata/explicit-subresource-path.yaml", &noExplicitVars)
if err != nil {
t.Error(err)
t.Fail()
@ -270,9 +285,12 @@ func TestExplicitSubresourcePathLoading(t *testing.T) {
Name: "parent/child",
Path: "parent-path/child-path",
Parent: "parent",
Values: make(map[string]interface{}, 0),
},
},
BaseDir: "testdata",
ImportedVars: make(map[string]interface{}, 0),
ExplicitVars: make(map[string]interface{}, 0),
}
if !reflect.DeepEqual(*ctx, expected) {
@ -283,22 +301,18 @@ func TestExplicitSubresourcePathLoading(t *testing.T) {
func TestSetVariablesFromArguments(t *testing.T) {
vars := []string{"version=some-service-version"}
ctx, _ := LoadContextFromFile("testdata/default-loading.yaml")
ctx, _ := LoadContext("testdata/default-loading.yaml", &vars)
if err := ctx.SetVariablesFromArguments(&vars); err != nil {
t.Error(err)
}
if version := ctx.Global["version"]; version != "some-service-version" {
if version := ctx.ExplicitVars["version"]; version != "some-service-version" {
t.Errorf(`Expected variable "version" to have value "some-service-version" but was "%s"`, version)
}
}
func TestSetInvalidVariablesFromArguments(t *testing.T) {
vars := []string{"version: some-service-version"}
ctx, _ := LoadContextFromFile("testdata/default-loading.yaml")
_, err := LoadContext("testdata/default-loading.yaml", &vars)
if err := ctx.SetVariablesFromArguments(&vars); err == nil {
if err == nil {
t.Error("Expected invalid variable to return an error")
}
}

3
context/testdata/import-vars-override.yaml vendored
View file

@ -6,4 +6,5 @@ global:
import:
- test-vars.yaml
- test-vars-override.yaml
include: []
include:
- name: test-set

7
main.go
View file

@ -184,16 +184,11 @@ func createCommand() {
}
func loadContextAndResources(file *string) (*context.Context, *[]templater.RenderedResourceSet) {
ctx, err := context.LoadContextFromFile(*file)
ctx, err := context.LoadContext(*file, variables)
if err != nil {
app.Fatalf("Error loading context: %v\n", err)
}
err = ctx.SetVariablesFromArguments(variables)
if err != nil {
app.Fatalf("Error setting explicit variables in context: %v\n", err)
}
resources, err := templater.LoadAndApplyTemplates(includes, excludes, ctx)
if err != nil {
app.Fatalf("Error templating resource sets: %v\n", err)

2
templater/templater.go
View file

@ -111,8 +111,6 @@ func templateFile(c *context.Context, rs *context.ResourceSet, filename string)
var b bytes.Buffer
rs.Values = *util.Merge(&c.Global, &rs.Values)
err = tpl.Execute(&b, rs.Values)
if err != nil {