generator

This is a general purpose OpenAPI code generator. It is currently used to completely generate the HTTP code in the Java SDK, and generate some of the HTTP code in our Golang SDK.

Usage

We currently have two HTTP endpoints. One for algod and one for indexer, so in most cases, this tool would be run once with each OpenAPI spec.

Build as a self-executing jar:

~$ mvn package -DskipTests
~$ java -jar target/generator-*-jar-with-dependencies.jar -h

You'll see that there are a number of subcommands:

• java - the original Java SDK generator.
• responses - generate randomized test files for SDK unit tests.
• template - a generator that uses velocity templates rather than Java code to configure the code generation.

Code layout

The command line interface uses JCommander to define the command line interface. See Main.java.

The main code involves an OpenAPI parser / event generator and several listeners for the actual generation.

Templates

The template subcommand is using Apache Velocity as the underlying template engine. Things like variables, loops, and statements are all supported. So business logic can technically be implemented in the template if it's actually necessary.

Template files

There are three phases: client, query, and model. Each phase must provide two templates, one for the file generation and one to specify the filename to be used. If all results should go to the same file. For query and model generation the template will be executed once for each query / model. If you want to put everything in one file return the same filename twice in a row and the processing will exit early.

phase	filename	purpose
client	client.vm	Client class with functions to call each query.
client	client_filename.vm	File to write to the client output directory.
query	query.vm	Template to use for generating query files.
query	query_filename.vm	File to write to the query output directory.
model	model.vm	Template to use for generating model files.
model	model_filename.vm	File to write to the model output directory.

Output directories

The template command will only run the templates which have an output directory is provided. So if you just want to regenerate models, only use the -m option.

  -c, --clientOutputDir
    Directory to write client file(s).
  -m, --modelsOutputDir
    Directory to write model file(s).
  -q, --queryOutputDir
    Directory to write query file(s).

Property files

The template subcommand accepts a --propertyFiles option. It can be provided multiple times, or as a comma separated list of files. Property files will be processed and bound to a velocity variable available to templates.

template variables

For details on a type you can put it directly into your template. It will be serialized along with its fields for your reference. Here is a high level description of what is available:

template	variable	type	purpose
all	str	StringHelpers.java	Some string utilities are available. See StringHelpers.java for details. There are simple things like $str.capitalize("someData") -> SomeData, and also some more complex helpers like $str.formatDoc($query.doc, "// ") which will split the document at the word boundary nearest to 80 characters without going over, and add a prefix to each new line.
all	order	OrderHelpers.java	Some ordering utilities available. See OrderHelpers.java for details. An example utility function is $order.propertiesWithOrdering($props, $preferred_order), where $props is a list of properties and $preferred_order is a string list to use when ordering the properties list.
all	propFile	Properties	The contents of all property files are available with this variable. For example if package=com.algorand.v2.algod is in the property file, the template may use ${propFile.package}.
all	models	HashMap<StructDef, List<TypeDef>>	A list of all models.
all	queries	List<QueryDef>	A list of all queries.
query	q	QueryDef	The current query definition.
model	def	StructDef	The current model definition if multiple files are being generated.
model	props	List<TypeDef>	A list of properties for the current model.

Example usage

In the following example, we are careful to generate the algod code first because the algod models are a strict subset of the indexer models. For that reason, we are able to reuse some overlapping models from indexer in algod.

~$ java -jar generator*jar template
        -s algod.oas2.json
        -t go_templates
        -c algodClient
        -m allModels
        -q algodQueries
        -p common_config.properties,algod_config.properties
~$ java -jar generator*jar template
        -s indexer.oas2.json
        -t go_templates
        -c indexerClient
        -m allModels
        -q indexerQueries
        -p common_config.properties,indexer_config.properties

Test Template

There is a test template that gives you some basic usage in the test_templates directory.

You can generate the test code in the output directory with the following commands:

~$ mkdir output
~$ java -jar target/generator-*-jar-with-dependencies.jar \
    template \
    -s /path/to/a/spec/file/indexer.oas2.json \
    -t test_templates/ \
    -m output \
    -q output \
    -c output \
    -p test_templates/my.properties

Golang Template

The Golang templates are in the go_templates directory.

The Golang HTTP API is only partially generated. The hand written parts were not totally consistent with the spec and that makes it difficult to regenerate them. Regardless, an attempt has been made. In the templates there are some macros which map "generated" values to the hand written ones. For example the query types have this mapping:

#macro ( queryType )
#if ( ${str.capitalize($q.name)} == "SearchForAccounts" )
SearchAccounts## The hand written client doesn't quite match the spec...
#elseif ( ${str.capitalize($q.name)} == "GetStatus" )
Status##
#elseif ( ${str.capitalize($q.name)} == "GetPendingTransactionsByAddress" )
PendingTransactionInformationByAddress##
#elseif ( ${str.capitalize($q.name)} == "GetPendingTransactions" )
PendingTransactions##
#else
${str.capitalize($q.name)}##
#end
#end

Other mappings are more specific to the language, such as the OpenAPI type to SDK type:

#macro ( toQueryType $param )##
#if ( $param.algorandFormat == "RFC3339 String" )
string##
#elseif ( $param.type == "integer" )
uint64##
#elseif ( $param.type == "string" )
string##
#elseif ( $param.type == "boolean" )
bool##
#elseif( $param.type == "binary" )
string##
#else
UNHANDLED TYPE
- ref: $!param.refType
- type: $!param.type
- array type: $!param.arrayType
- algorand format: $!param.algorandFormat
- format: $!param.format
##$unknown.type ## force a template failure because $unknown.type does not exist.
#end
#end

Because of this, we are phasing in code generation gradually by skipping some types. The skipped types are specified in the property files:

common_config.properties

model_skip=AccountParticipation,AssetParams,RawBlockJson,etc,...

algod_config.properties

query_skip=Block,BlockRaw,SendRawTransaction,SuggestedParams,etc,...

indexer_config.properties

query_skip=LookupAssetByID,LookupAccountTransactions,SearchForAssets,LookupAssetBalances,LookupAssetTransactions,LookupBlock,LookupTransactions,SearchForTransactions

Java Template

The Java templates are in the java_templates directory.

These are not used yet, they are the initial experiments for the template engine. Since the Java SDK has used code generation from the beginning, we should be able to fully migrate to the template engine eventually.

Automation

Preparing an external repository for automatic code generation

In general, the automation pipeline will build and run whatever Dockerfile is found in a repository's templates directory. For instructions on how to configure the templates directory, look at the repository template directory example.

If you are trying to verify that automatic code generation works as intended, we recommend creating a testing branch from that repository and using the SKIP_PR=true environment variable to avoid creating pull requests. If all goes according to plan, generated files should be available in the container's /repo directory.

Setting up the automatic generator

The automatic generator scripts depend on certain prerequisites that are listed in automation/REQUIREMENTS.md. Once those conditions have been satisfied, automatically generating code for external repositories should be as easy as building and running a particular SDK's templates/Dockerfile file.