updated readme

Author: yunchengyang515

README.md

@@ -1,2 +1,77 @@
 # stackql-exec
 Github Action as a wrapper for executing a single command in stackql, maps all stackql exec args to actions args
+
+# Usage
+
+## Basic Example
+```
+    - name: exec github example
+      uses: ./
+      with:
+        auth_str: '{ "github": { "type": "basic", "credentialsenvvar": "STACKQL_GITHUB_CREDS" } }'
+        query: "REGISTRY PULL github v23.01.00104;
+                SHOW PROVIDERS;
+                select total_private_repos
+                from github.orgs.orgs
+                where org = 'stackql';"
+      env: 
+        STACKQL_GITHUB_CREDS: ${{ secrets.STACKQL_GITHUB_CREDS }}
+
+```
+
+
+## Auth json file and query file example
+- `auth.json`
+```
+{   "google": { "type": "service_account",  "credentialsfilepath": "sa-key.json" },
+    "github": { "type": "basic", "credentialsenvvar": "STACKQL_GITHUB_CREDS" }}
+```
+- `google-example.iql`
+```
+REGISTRY PULL github v23.01.00104;
+SHOW PROVIDERS;
+select total_private_repos
+from github.orgs.orgs
+where org = 'stackql';
+```
+**Example**
+```
+    - name: Prep Google Creds (Windows)
+      if: ${{ matrix.os == 'windows-latest'}}
+      run: | ## use the secret to create json file
+        $GoogleCreds = [System.Environment]::GetEnvironmentVariable("GOOGLE_CREDS_ENV")
+        $GoogleCredsDecoded = [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($GoogleCreds))
+        Write-Output $GoogleCredsDecoded | Set-Content sa-key.json
+      shell: pwsh
+      env:
+        GOOGLE_CREDS_ENV: ${{ secrets.GOOGLE_CREDS }}
+  
+    - name: Prep Google Creds (bash)
+      if: ${{ matrix.os != 'windows-latest' }}
+      shell: bash
+      run: | ## use the base64 encoded secret to create json file
+        sudo echo ${{ secrets.GOOGLE_CREDS }} | base64 -d > sa-key.json
+
+    - name: exec google example
+      uses: ./
+      with:
+        auth_obj_path: './stackql_scripts/auth.json'
+        query_file_path: './stackql_scripts/google-example.iql'
+```
+
+
+## Input
+- `auth_obj_path` - (optional) the path of json file that stores stackql AUTH string
+- `auth_str` - (optional) stackql AUTH string, need either auth_str or auth_obj_path
+- `query` - (optional) stackql query to execute
+- `query_file_path` - (optional) stackql query file to execute, need either query or query_file_path
+- `query_output` - (optional) output format of the stackql exec result, accept "table", "csv", "json", default to "json"
+
+
+## Outputs
+This action uses [setup-stackql](https://github.com/marketplace/actions/stackql-studio-setup-stackql), with use_wrapper set
+to `true`, the following outputs are available for subsequent steps that call the `stackql` binary:
+
+- `stdout` - The STDOUT stream of the call to the `stackql` binary.
+- `stderr` - The STDERR stream of the call to the `stackql` binary.
+- `exitcode` - The exit code of the call to the `stackql` binary.