string Concatenate in yml file and use with aspnetcore 2.1 - asp.net-core

Question

yml string concatenate does not work with .NET applications.I have tried by removing '$' sign, but it is still not working(Java application uses $ sign - Working fine with Java apps). It is working fine for a single value, but not with concatenation.
yml-01
cicd:
dbname: 172.10.10.110
port: 5432
yml-02
datasource:
url: jdbc:postgresql://${cicd:dbname}:${cicd:port}/sample-db

Answer 1

A solution for placeholder resolution in .NET Configuration (similar to that provided by spring) is available in Steeltoe.Common. We haven't added WebHostBuilder or IConfigurationBuilder extensions just yet, but if you add a recent reference to Steeltoe.Common from the Steeltoe Dev feed you should be able to do something like this:
public static IWebHostBuilder ResolveConfigurationPlaceholders(this IWebHostBuilder hostBuilder, LoggerFactory loggerFactory = null)
{
return hostBuilder.ConfigureAppConfiguration((builderContext, config) =>
{
config.AddInMemoryCollection(PropertyPlaceholderHelper.GetResolvedConfigurationPlaceholders(config.Build(), loggerFactory?.CreateLogger("Steeltoe.Configuration.PropertyPlaceholderHelper")));
});
}
The code above is used in the Steeltoe fork of eShopOnContainers

Answer 2

You should take a look at YamlDotNet.
Here's an example of how to solve your problem using that lib
using YamlDotNet.RepresentationModel;
using YamlDotNet.Core;
Then in your method
var dbname = "172.10.10.110";
var port = "5432";
string content;
using (var reader = new StreamReader("your yml file"))
{
content = reader.ReadToEnd();
}
var doc = new StringReader(content);
var yaml = new YamlStream();
yaml.Load(doc);
// Add the url where you use string interpolation to replace the values
var ymlFile = (YamlMappingNode)yaml.Documents[0].RootNode;
ymlFile.Children["datasource"] = new YamlMappingNode
{
{ "url", $"jdbc:postgresql://{dbname}:{port}/sample-db" }
};
yaml.Save(File.CreateText("C:\\yourNewFile.yml"), assignAnchors: false);
Here's a link to the NetCore package

Answer 3

I've solved this by writing an extension method to the IConfiguration interface.
public static string ReadFromConfigRepo(this IConfiguration configuration, string key)
{
var pattern = #"\{(.*?)\}";
var query = configuration[key];
if (query.Contains('{'))
{
var matches = Regex.Matches(query, pattern);
string value;
foreach (Match m in matches)
{
value = configuration[m.Value.Substring(1, m.Value.Length - 2)];
query = query.Replace(m.Value, value);
}
}
return query.Trim();
}