chore: use mustache

README.md

@@ -1,5 +1,5 @@
 # Test Message Generator
-This small tool helps to generate (test) messages based on a template. It can act as a simple replacement for message source systems and allows to send on regular time intervals some data, based on a template that gets altered before sending based on a mapping.
+This small tool helps to generate (test) messages based on a [Mustache](https://mustache.github.io/) template. It can act as a simple replacement for message source systems and allows to send on regular time intervals some data, based on a template that gets altered before sending.
 
 ## Docker
 The generator can be run as a Docker container, after creating a Docker image for it. The Docker container will keep running until stopped.
@@ -11,14 +11,14 @@ docker build --tag vsds/test-message-generator .
 
 To run the generator, you can use:
 ```bash
-docker run -v $(pwd)/data:/tmp/data -e TEMPLATEFILE=/tmp/data/other.template.json -e MAPPINGFILE=/tmp/data/other.mapping.json vsds/test-message-generator
+docker run -v $(pwd)/data:/tmp/data -e TEMPLATEFILE=/tmp/data/template.json vsds/test-message-generator
 ```
 You can also pass the following arguments when running the container:
-* `TARGETURL=<target-uri>` to POST the output to the target URI instead of to the console
 * `SILENT=true` to display no logging to the console
-* `MIMETYPE=<mime-type>` to use a different mime-type
+* `TARGETURL=<target-uri>` to POST the output to the target URI instead of to the console
+* `MIMETYPE=<mime-type>` to specify a mime-type when POSTing
 
-Alternatively, you can also pass the template and mapping as string instead of as files, use `TEMPLATE` respectively `MAPPING`.
+Alternatively, you can also pass the template as string instead of as file, use `TEMPLATE`.
 
 ## Build the Generator
 The generator is implemented as a [Node.js](https://nodejs.org/en/) application.
@@ -29,11 +29,11 @@ npm run build
 ```
 
 ## Run the Generator
-The generator works based on a JSON template, defining the structure to use for each generated item, and a JSON mapping file, defining the transformations that need to be performed on the template. It can send the generated JSON data to a target URL or simply send it to the console.
+The generator works based on a template, defining the structure to use for each generated item. It can send the generated data to a target URL or simply send it to the console.
 
 The generator takes the following command line arguments:
 * `--silent=<true|false>` prevents any console debug output if true, defaults to false (not silent, logging all debug info)
-* `--targetUrl` defines the target URL to where the generated JSON is POST'ed as `application/json`, no default (if not provided, sends output to console independant of `--silent`)
+* `--targetUrl` defines the target URL to where the generated message is POST'ed as the configured mime-type, no default (if not provided, sends output to console independant of `--silent`)
 > **Note**: alternatively, you can provide the target URL as a plain text in a file named `TARGETURL` (located in the current working directory) allowing to change the target URL at runtime as the file is read at cron schedule time (see below), e.g.:
 > ```bash
 > echo http://example.org/my-ingest-endpoint > ./TARGETURL
@@ -43,35 +43,28 @@ The generator takes the following command line arguments:
 > ```bash
 > echo https://webhook.site/f140204a-9514-4bfa-8d3e-fd18ba325ee3 > ./TARGETURL
 > ```
-* `--mimeType=<mime-type>` mime-type of message send to target URL, defaults to `application/json`
+* `--mimeType=<mime-type>` mime-type of message send to target URL, no default
 * `--cron` defines the time schedule, defaults to `* * * * * * ` (every second)
-* `--template='<json-content>'` allows to provide the JSON template on the command line, no default (if not provided, you MUST provide `--templateFile`)
-* `--templateFile=<partial-or-full-pathname>` allows to provide the JSON template in a file, no default (if not provided, you MUST provide `--template`)
-* `--mapping='<json-content>'` allows to provide the JSON mapping on the command line, no default (if not provided, you MUST provide `--mappingFile`)
-* `--mappingFile=<partial-or-full-pathname>` allows to provide the JSON mapping in a file, no default (if not provided, you MUST provide `--mapping`)
+* `--template='<content>'` allows to provide the template on the command line, no default (if not provided, you MUST provide `--templateFile`)
+* `--templateFile=<partial-or-full-pathname>` allows to provide the template in a file, no default (if not provided, you MUST provide `--template`)
 
-The template or template file should simply contain a valid JSON structure (with one or more JSON objects). E.g.:
+The template or template file should simply contain a message with mustache variables (between `{{` and `}}`). E.g.:
 ```json
 [
-    { "id": "my-id", "type": "Something", "modifiedAt": "2022-09-09T09:10:00.000Z" },
-    { "id": "my-other-id", "type": "SomethingElse", "modifiedAt": "2022-09-09T09:10:00.000Z" }
+    { "id": "my-id-{{index}}", "type": "Something", "modifiedAt": "{{timestamp}}" },
+    { "id": "my-other-id-{{index}}", "type": "SomethingElse", "modifiedAt": "{{timestamp}}" }
 ]
 ```
 
-The mapping file is also a JSON file but uses a key/value mapping where the key conforms the [JSON path specifications](https://datatracker.ietf.org/doc/id/draft-goessner-dispatch-jsonpath-00.html) and the value conforms a syntax allowing to change the value matched by the JSON path to a new value obtained by replacing the variables specified in the value part, e.g.:
-```json
-{ "$.id": "${@}-${nextCounter}", "$.modifiedAt": "${currentTimestamp}" }
-```
-
-The `${@}` will be replaced by the currently match value of the JSON path `$.id` (e.g. `my-id`) while any other `${<property>}` will use a property of the generator itself. Currently the only allowed properties are:
-* `nextCounter`: increasing integer value, starting from 1
-* `currentTimestamp`: current date and time formatted as [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) in UTC (e.g. `2007-04-05T14:30:00.000Z`)
+Currently the only allowed variables are:
+* `index`: increasing integer value, starting from 1
+* `timestamp`: current date and time formatted as [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) in UTC (e.g. `2007-04-05T14:30:00.000Z`)
 
 You can run the generator after building it, e.g.:
 
-Using this [template](./data/other.template.json) and this [mapping](./data//other.mapping.json) and with silent output to console:
+Using this [template](./data/template.json) and with silent output to console:
 ```bash
-node ./dist/index.js --templateFile ./data/other.template.json --mappingFile ./data/other.mapping.json --silent
+node ./dist/index.js --templateFile ./data/template.json --silent
 ```
 This results in something like the following:
 ```
@@ -80,9 +73,10 @@ This results in something like the following:
 {"id":"my-id-3","type":"Something","modifiedAt":"2022-09-12T13:15:44.003Z"}
 ...
 ```
+
 By specifying the template (containing multiple objects) and mapping on the command file:
 ```bash
-node ./dist/index.js --template '[{"id": "my-id", "type": "Something", "modifiedAt": "2022-09-09T09:10:00.000Z" },{ "id": "my-other-id", "type": "SomethingElse", "modifiedAt": "2022-09-09T09:10:00.000Z" }]' --mapping '{ "$..id": "${@}-${nextCounter}", "$..modifiedAt": "${currentTimestamp}" }' --silent
+node ./dist/index.js --template '[{"id": "my-id-{{index}}", "type": "Something", "modifiedAt": "{{timestamp}}" },{ "id": "my-other-id-{{index}}", "type": "SomethingElse", "modifiedAt": "{{timestamp}}" }]' --silent
 ```
 This results in something like:
 ```json
@@ -94,14 +88,13 @@ This results in something like:
 
 Alternatively you can generate the output using a different time schedule (e.g. every 2 seconds) to a [dummy HTTP server](https://docs.webhook.site/) (including debugging to the console):
 ```bash
-node ./dist/index.js --templateFile ./data/other.template.json --mappingFile ./data/other.mapping.json --cron '*/2 * * * * *' --targetUrl https://webhook.site/ce3065f5-2f0b-49d8-8856-330ae3c6e737
+node ./dist/index.js --templateFile ./data/template.json --cron '*/2 * * * * *' --targetUrl https://webhook.site/ce3065f5-2f0b-49d8-8856-330ae3c6e737 --mimeType application/json
 ```
 This results in:
 ```
 Arguments:  {
   _: [],
-  templateFile: './data/other.template.json',
-  mappingFile: './data/other.mapping.json',
+  templateFile: './data/template.json',
   cron: '*/2 * * * * *',
   targetUrl: 'https://webhook.site/ce3065f5-2f0b-49d8-8856-330ae3c6e737'
 }

data/template.json

@@ -0,0 +1 @@
+{ "id": "my-id-{{index}}", "type": "Something", "modifiedAt": "{{timestamp}}" }