Function inject_session_state

src/google/adk/utils/instructions_utils.py:30–124

Populates values in the instruction template, e.g. state, artifact, etc. This method is intended to be used in InstructionProvider based instruction and global_instruction which are called with readonly_context. e.g. ``` ... from google.adk.utils.instructions_utils import inject_sessio

(
    template: str,
    readonly_context: ReadonlyContext,
)

async def inject_session_state(
    template: str,
    readonly_context: ReadonlyContext,
) -> str:
  """Populates values in the instruction template, e.g. state, artifact, etc.

  This method is intended to be used in InstructionProvider based instruction
  and global_instruction which are called with readonly_context.

  e.g.
  ```
  ...
  from google.adk.utils.instructions_utils import inject_session_state

  async def build_instruction(
      readonly_context: ReadonlyContext,
  ) -> str:
    return await inject_session_state(
        'You can inject a state variable like {var_name} or an artifact '
        '{artifact.file_name} into the instruction template.',
        readonly_context,
    )

  agent = Agent(
      model="gemini-2.5-flash",
      name="agent",
      instruction=build_instruction,
  )
  ```

  Args:
    template: The instruction template.
    readonly_context: The read-only context

  Returns:
    The instruction template with values populated.
  """

  invocation_context = readonly_context._invocation_context

  async def _async_sub(pattern, repl_async_fn, string) -> str:
    result = []
    last_end = 0
    for match in re.finditer(pattern, string):
      result.append(string[last_end : match.start()])
      replacement = await repl_async_fn(match)
      result.append(replacement)
      last_end = match.end()
    result.append(string[last_end:])
    return ''.join(result)

  async def _replace_match(match) -> str:
    var_name = match.group().lstrip('{').rstrip('}').strip()
    optional = False
    if var_name.endswith('?'):
      optional = True
      var_name = var_name.removesuffix('?')
    if var_name.startswith('artifact.'):