protected override async Task InitializeAsync(ILambdaConfigSource envSource, ILambdaContext context)
{
await base.InitializeAsync(envSource, context);
// retrieve the optional parameter name for the slack token
_slackVerificationTokenName = envSource.Read("SLACKTOKENNAME");
}
protected virtual async Task InitializeAsync(ILambdaConfigSource envSource, ILambdaContext context)
{
// read configuration from environment variables
DeploymentTier = envSource.Read("TIER");
ModuleName = envSource.Read("MODULE");
_deadLetterQueueUrl = envSource.Read("DEADLETTERQUEUE");
_loggingTopicArn = envSource.Read("LOGGINGTOPIC");
var framework = envSource.Read("LAMBDARUNTIME");
LogInfo($"TIER = {DeploymentTier}");
LogInfo($"MODULE = {ModuleName}");
LogInfo($"DEADLETTERQUEUE = {_deadLetterQueueUrl ?? "NONE"}");
LogInfo($"LOGGINGTOPIC = {_loggingTopicArn ?? "NONE"}");
// read optional git-sha file
var gitsha = File.Exists("gitsha.txt") ? File.ReadAllText("gitsha.txt") : null;
LogInfo($"GITSHA = {gitsha ?? "NONE"}");
// convert environment variables to lambda parameters
_appConfig = new LambdaConfig(new LambdaDictionarySource(await ReadParametersFromEnvironmentVariables()));
// initialize rollbar
var rollbarAccessToken = _appConfig.ReadText("RollbarToken", defaultValue: null);
const string proxy = "";
const string platform = "lambda";
_rollbarClient = RollbarClient.Create(new RollbarConfiguration(
// NOTE (2018-08-06, bjorg): the rollbar access token determines the rollbar project
// the error report is associated with; when rollbar intergration is disabled,
// use the module name instead so the logging recipient can determine the module
// the log entry belongs to.
rollbarAccessToken ?? ModuleName,
proxy,
DeploymentTier,
platform,
framework,
gitsha
));
_rollbarEnabled = (rollbarAccessToken != null);
LogInfo($"ROLLBAR = {(_rollbarEnabled ? "ENABLED" : "DISABLED")}");
}
//--- Methods ---
public T Read <T>(string key, Func <string, T> fallback, Func <string, T> convert, Action <T> validate)
{
// attempt to read the requested key
string textValue;
try {
textValue = _source.Read(key);
} catch (Exception e) when(!(e is ALambdaConfigException))
{
throw new LambdaConfigUnexpectedException(CombinePathWithKey(Path, key), "reading config key", e);
}
// check if we were unable to find a value
T value;
if (textValue == null)
{
// check if we have a fallback option for getting the value
if (fallback == null)
{
throw new LambdaConfigMissingKeyException(CombinePathWithKey(Path, key));
}
// attempt to get the key value using the fallback callback
try {
value = fallback(key);
} catch (Exception e) when(!(e is ALambdaConfigException))
{
throw new LambdaConfigUnexpectedException(CombinePathWithKey(Path, key), "invoking fallback", e);
}
}
else
{
// attempt to convert value to desired type
try {
if (convert == null)
{
value = (T)Convert.ChangeType(textValue, typeof(T));
}
else
{
value = convert(textValue);
}
} catch (Exception e) when(!(e is ALambdaConfigException))
{
throw new LambdaConfigUnexpectedException(CombinePathWithKey(Path, key), "validating value", e);
}
}
// optionally validate converted value
if (validate == null)
{
return(value);
}
try {
validate(value);
} catch (Exception e) when(!(e is ALambdaConfigException))
{
throw new LambdaConfigBadValueException(CombinePathWithKey(Path, key), e);
}
return(value);
}
//--- Methods ---
/// <summary>
/// The <see cref="InitializePrologueAsync(ILambdaConfigSource)"/> method is invoked to prepare the Lambda function
/// for initialization. This is the first of three methods that are invoked to initialize the Lambda function.
/// </summary>
/// <param name="envSource">The <see cref="ILambdaConfigSource"/> instance from which to read the configuration settings.</param>
/// <returns>The task object representing the asynchronous operation.</returns>
protected override async Task InitializePrologueAsync(ILambdaConfigSource envSource)
{
await base.InitializePrologueAsync(envSource);
_corsOrigin = envSource.Read("CORS_ORIGIN");
}
protected virtual async Task InitializeAsync(ILambdaConfigSource envSource, ILambdaContext context)
{
// read configuration from environment variables
DeploymentTier = envSource.Read("TIER");
ModuleName = envSource.Read("MODULE");
_deadLetterQueueUrl = envSource.Read("DEADLETTERQUEUE");
_loggingTopicArn = envSource.Read("LOGGINGTOPIC");
var framework = envSource.Read("LAMBDARUNTIME");
LogInfo($"TIER = {DeploymentTier}");
LogInfo($"MODULE = {ModuleName}");
LogInfo($"DEADLETTERQUEUE = {_deadLetterQueueUrl ?? "NONE"}");
LogInfo($"LOGGINGTOPIC = {_loggingTopicArn ?? "NONE"}");
// read optional git-sha file
var gitsha = File.Exists("gitsha.txt") ? File.ReadAllText("gitsha.txt") : null;
LogInfo($"GITSHA = {gitsha ?? "NONE"}");
// read module parameter values from parameters file
var parameters = await ParseParameters("/", File.ReadAllText("parameters.json"));
// create config where environment variables take precedence over those found in the parameter file
_appConfig = new LambdaConfig(new LambdaMultiSource(new[] {
envSource,
new LambdaDictionarySource("", parameters)
}));
// initialize rollbar
var rollbarAccessToken = _appConfig.ReadText("RollbarToken", defaultValue: null);
const string proxy = "";
const string platform = "lambda";
_rollbarClient = RollbarClient.Create(new RollbarConfiguration(
// NOTE (2018-08-06, bjorg): the rollbar access token determines the rollbar project
// the error report is associated with; when rollbar intergration is disabled,
// use the module name instead so the logging recipient can determine the module
// the log entry belongs to.
rollbarAccessToken ?? ModuleName,
proxy,
DeploymentTier,
platform,
framework,
gitsha
));
_rollbarEnabled = (rollbarAccessToken != null);
LogInfo($"ROLLBAR = {(_rollbarEnabled ? "ENABLED" : "DISABLED")}");
// local functions
async Task <Dictionary <string, string> > ParseParameters(string parameterPrefix, string json)
{
var functionParameters = JsonConvert.DeserializeObject <Dictionary <string, LambdaFunctionParameter> >(json);
var flatten = new Dictionary <string, string>();
await Flatten(functionParameters, parameterPrefix, "STACK_", flatten);
return(flatten);
// local functions
async Task Flatten(Dictionary <string, LambdaFunctionParameter> source, string prefix, string envPrefix, Dictionary <string, string> target)
{
foreach (var kv in source)
{
var value = kv.Value.Value;
switch (kv.Value.Type)
{
case LambdaFunctionParameterType.Collection:
await Flatten((Dictionary <string, LambdaFunctionParameter>) value, prefix + kv.Key + "/", envPrefix + kv.Key.ToUpperInvariant() + "_", target);
break;
case LambdaFunctionParameterType.Secret: {
var secret = (string)value;
var plaintextStream = (await _kmsClient.DecryptAsync(new DecryptRequest {
CiphertextBlob = new MemoryStream(Convert.FromBase64String(secret)),
EncryptionContext = kv.Value.EncryptionContext
})).Plaintext;
target.Add(prefix + kv.Key, Encoding.UTF8.GetString(plaintextStream.ToArray()));
break;
}
case LambdaFunctionParameterType.Stack:
target.Add(prefix + kv.Key, envSource.Read(envPrefix + kv.Key.ToUpperInvariant()));
break;
case LambdaFunctionParameterType.Text:
target.Add(prefix + kv.Key, (string)value);
break;
default:
throw new NotSupportedException($"unsupported parameter type: '{kv.Value.Type.ToString()}'");
}
}
}
}
}